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January 1986

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Document:	AA-0988D-TB Link Reference Manual Apr86
Order Number:	AD-0988D-T2
Revision:	0
Pages:	272
Original Filename:	AA-0988D-TB_Link_Reference_Manual_Apr86.pdf

OCR Text

TOPS-10
LINK Reference Manual
AA-09880-TB, AO-09880-T1, AO-09880-T2

April 1986
This document describes LlNK-l0, the linking loader for
TOPS-10.
This document updates the document of the same name,
order number AA-0988D-TB, published March 1983.

OPERATING SYSTEM:

TOPS-l0 V7.03

SOFTWARE:

LlNK-l0 V6.0

Software and manuals should be ordered by title and order number. In the United States. send orders
to the nearest distribution center. Outside the United States. orders should be directed to the nearest
DIGITAL Field Sales Office or representative.

Western Region

Northeast/Mid-Atlantic Region

Central Region

Digital Equipment Corporation
PO Box CS2008
Nashua, New Hampshire 03061
Telephone:(603)884-6660

Digital Equipment Corporation
Digital Equipment Corporation
Accessories and Supplies Center Accessories and Supplies Center
1050 East Remington Road
632 Caribbean Drive
Schaumburg, Illinois 60195
Sunnyvale. California 94086
Telephone:(312)640--5612
Telephone:(408)734-4915

digital equipment corporation. marlboro. massachusetts

First Printing, May 1973
Revised, July 1974
Revised, December 1975
Revised, April 1978
Updated, June 1978
Revised, March 1983
Updated, January 1985
Updated, April 1986
Copyright ©1973, 1983, 1986 by Digital Equipment Corporation. All Rights Reserved.

The information in this document is subject to change without notice and should not
be construed as a commitment by Digital Equipment Corporation. Digital Equipment
Corporation assumes no responsibility for any errors that may appear in this document.
The software described in this document is furnished under a license and may be
used or copied only in accordance with the terms of such license.
No responsibility is assumed for the use or reliability of software on equipment that is
not supplied by Digital Equipment Corporation or its affiliated companies.

The following are trademarks of Digital Equipment Corporation:
DEC
DECmate
DECsystem-lO
DECSYSTEM-20
DECUS
DECwriter
DIBOL

MASSBUS
PDP
P/OS
Professional
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RSTS

RSX
RT
UNIBUS
VAX
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Work Processor

The postpaid READER'S COMMENTS form on the last page of this document requests
the user's critical evaluation to assist us in preparing future documentation.

CONTENTS

CHAPTER 1
1.1
1.1.1
1.1.2
1.1.3
1.2
1.3
1.4
1.5
CHAPTER 2
2.1
2.2
2.3
CHAPTER 3
3.1
3.2
3.2.1
3.2.2
3.3
3.4
CHAPTER 4
4.1
4.2
4.2.1
4.2.1.1
4.2.2
4.2.3
4.2.4
4.3
4.4
CHAPTER 5
5.1
5.1.1
5.1.2
5.2
5.2.1
5.2.2
5.3
5.3.1
5.3.2
5.4
5.4.1
5.4.2
5.4.3
5.5
5.6
5.7

INTRODUCTION TO LINK
INPUT TO LINK
. • • . • . . • . 1-1
Object Modules •
• 1-1
Commands to Link
• 1-2
Libraries • • • •
• • • • • 1-2
OUTPUT FROM LINK • • • • •
1-2
LINK'S OVERLAY FACILITY
1-3
LINK AND EXTENDED ADDRESSING •
• 1-3
USING LINK • • • • • • • • • • • . . . . . . . . . 1-4
USING LINK AUTOMATICALLY
COMMAND FORMATS • • • • • • • • • •
COMMAND SWITCHES • • • • • • • • • • •
EXAMPLE OF USING LINK AUTOMATICALLY

• • • • • 2-1
• 2-2
• • 2-3

USING LINK DIRECTLY
COMMAND STRING FORMAT
SWITCHES TO LINK • • •
Command Scanner Switches •
Link Switches • • • • • • • • • .
LIBRARIES AND SEARCHES • • •
EXAMPLES USING LINK DIRECTLY •

• 3-2
• • 3-3
3-3
. . • . • 3-4
• • ••
3-81
3-81

OUTPUT FROM LINK
THE EXECUTABLE PROGRAM
OUTPUT FILES • • • • •
Executable Files • •
Format of Sharable
LOG Files • • • •
Map files
•••••
Symbol Files • • • •
SYMBOL TABLE VECTOR
MESSAGES • • • • • • •

• • • • • •
• • • • • • • •
• • • • • •
Save Files • •
• • • • • •
•

•
• ••
•
• •••••
• •
•
•
••••••
•
• • • •
•
• • • • •
•

4-1
4-1
4-2
4-2
4-5
4-5
4-5
4-5
4-7

OVERLAY STRUCTURES • • • • • •
Defining Overlay Structures
An Overlay Example • • • • •
WRITABLE OVERLAYS • • • • • •
Writable Overlay Syntax
Writable Overlay Error Messages
RELOCATABLE OVERLAYS • • • • • •
Relocatab1e Overlay Syntax • • • • •
Relocatable Overlay Messages • • • •
RESTRICTIONS ON OVERLAYS • • • • •
Restrictions on Absolute Overlays
Restrictions on Re1ocatab1e Overlays
Restrictions on FORTRAN Overlays
SIZE OF OVERLAY PROGRA~S • •
DEBUGGING OVERLAYED PROGRAMS
THE OVERLAY HANDLER • • • •

• • • 5-1
• • • • • • 5-2
• 5-4
5-10
5-10
5-10
• • • • 5-11
5-11
• • •
• •
5-11
5-12
5-12
• • • • • 5-13
5-13
5-14
• • • ••
5-14
5-14

OVERLAYS

iii

April 1986

5.7.1
5.7.2
5.7.3
5.7.4
5.8
5.8.1
5.8.2
5.8.3
5.8.4
CHAPTER 6
6.1
6.2
6.2.1

Calls to the Overlay Handler
Overlay Handler Subroutines
Overlay Handler Messages
The FUNCT. Subroutine
THE OVERLAY (OVL) FILE
The Directory Block
The Link Number Table
The Link Name Table
The Overlay Link

·
. . ·· .

PSECTs
LOADING PROGRAMS WITH PSECTs • •
PSECT ATTRIBUTES • • • • • • • • • •
CONCATENATED and OVERLAID

APPENDIX A

REL BLOCKS

APPENDIX B

LINK MESSAGES

B.l
B.2
B.3
APPENDIX C

5-15
· · · · 5-16
5-21
.·····
5-30
. · · · · · · · · 5-24
5-31
·· ·· ··· ··· ··· ··· ·· ·· 5-32
5-32
5-33
····

DESCRIPTION OF MESSAGES
LIST OF MESSAGES
INDEXED MESSAGES • • • •

6-1
• 6-3
• • • • 6-3

• B-1
• • • B-4
B-32

JOB DATA AREA LOCATIONS SET BY LINK

INDEX
TABLES
2-1
5-1
B-1
B-2

Switches for System Commands • • • • • • • •
•
Example of an Overlay Structure
• • • • • •
Severity Codes • • • • • • • • •
• •••••
Special Message Segments • • • • • • • • •
• •

2-2
5-2
B-2
B-3

April 1986

PREFACE

This manual is the reference document for LINK,
the TOPS-IO linking
loader.
The manual is aimed at the intermediate to highly-experienced
applications programmer, and contains complete documentation of LINK.
Chapter I provides a general introduction to LINK.
Chapter 2 describes automatic use of LINK through one of the system
commands DEBUG, EXECUTE, or LOAD.
This chapter is sufficient for most
loading tasks.
Chapter 3 describes direct use of LINK.
This discussion is useful for
large or complicated loads.
This chapter also discusses libraries and
library searches.
Chapter 4 describes output from LINK~
executable programS, most
output files,
and LINK messages.
Included are descriptions of the
internal format of save (.EXE) files.
Chapter 5
discusses
overlays,
including
overlay
structures,
overlay-related output files,
the overlay handler and its messages,
and the FUNCT. subroutine.
This chapter has an extensive example of
an overlay load. Many of the elements of this example are of interest
outside the context of overlays.
Appendix A gives a technical description of the output
language translators, which is in the form of REL Blocks.
Appendix B lists all LINK messages.
Appendix C describes the job data area.
The current copies of TOPS-IO documents are also useful:
TOPS-IO Utilities Manual
TOPS-IO Operating System Commands Manual
TOPS-IO MAKLIB User's Guide
TOPS-IO/TOPS-20 MACRO Assembly Reference Manual
TOPS-IO/TOPS-20 COBOL-68 Language Manual
TOPS-IO/TOPS-20 COBOL-74 Language Manual
TOPS-IO/TOPS-20 SPEAR Manual
TOPS-IO/TOPS-20 ALGOL Programmer's Guide
TOPS-IO/TOPS-20 FORTRAN Language Manual
Update
DECsystem-IO/DECSYSTEM-20
Processor Reference Manual
v

from

the

CHAPTER 1
INTRODUCTION TO LINK

LINK is the TOPS-IO's linking
loader.
It merges
independently
compiled or assembled modules into a single executable program.
This merging process requires LINK to perform the following functions:
1.

Perform the relocation calculations by converting relocatable
addresses to virtual addresses, and by binding segments and
PSECTs to addresses.

Resolve global symbol
references by
Polish fixups, and library searches.

Produce an executable program by providing
information and a DDT runtime symbol table.

global

chain

fixups,

some

JOBDAT

The virtual address space used
for
loading your program is not
hardware memory.
During loading and execution, the system simulates
this virtual space by swapping code between disk and hardware memory
as
required.
For simplicity, we will refer to the virtual address
space as memory.

1.1

INPUT TO LINK

The primary input to LINK is the output from the language translators;
it is a binary file containing machine language code corresponding to
your program, called object modules.
Other
input may include your
commands to LINK, and libraries containing object modules.

1.1.1

Object Modules

An object module is output from a language translator;
it is part of
a
binary
file
(REL
file)
containing machine language code
corresponding to your program.
This file is formatted
into blocks,
called REL Blocks, that LINK recognizes and can handle appropriately.
The format of each REL Block Type is described in Appendix A.
Most object modules contain relocatable code.
This means that the
addresses
in the module are relative to the zero address.
LINK loads
the relocatable code at an arbitrary memory address,
but adds a
constant to each address
referenced in the program.
This resolves
relative addresses to absolute addresses.

1-1

INTRODUCTION TO LINK

Using relocatable code simplifies your programming task.
Your
programming
task
is simpler because you need not worry about the
loading addresses of your programs.
Besides relocating and loading your object modules,
LINK resolves
values for global symbols:
those that are defined in one module and
used in others.
LINK also resolves references to entry name symbols
when modules containing these symbols are loaded.
Using symbols in your programs makes your programming simpler.
If you
need to revise a program, it is much easier to change the value of a
symbol
than to change each occurrence of the value.
This is
especially important for global
symbols.
You need only change the
value in the defining module;
the other modules do not need
retranslation.

1.1.2

Commands to Link

LINK is controlled during loading by the command strings you give.
Commands consist of file specifications and switches.
LINK command
strings are discussed in Chapter 3.

1.1.3

Libraries

A library is a file containing object modules that may be needed
to
resolve references ln your program.
For example, the FORTRAN library
FORLIB contains subroutines that may be referenced by the output from
the FORTRAN compiler.
When loading FORTRAN-compiled code,
LINK
usually searches this library to satisfy any unresolved subroutine
calls.
Most language translators have their own libraries.
You can construct your own libraries, and have LINK
necessary subroutines.
Libraries and searching
Section 3.4.

1.2

search them for
are discussed in

OUTPUT FROM LINK

The primary output from LINK is the executable program,
called the
core image.
In the core image, all addresses are resolved to absolute
memory locations, and all symbols
(including subroutine calls)
are
resolved to absolute values or addresses.
This core image may be executed immediately or saved as a sharable
save (.EXE) file.
The .EXE file may be created automatically by LINK.
This occurs if you specify /SSAVE when you run LINK, or if the program
is too complex to be left in core with LINK.
You can also execute the core image under the control of
program.

debugging

During its processing, LINK generates messages, which are output to
your
terminal or a
log file.
Some of these give information about
LINK's operation;
some warn you about possible problems;
some
identify errors.
LINK messages are described in Appendix B.

1-2

INTRODUCTION TO LINK
At your option, LINK can generate three special files: the map file,
the log file, and the symbol file. The map file contains information
about symbols in your program modules. The log file records LINK's
messages so that you can save them. The symbol file contains a symbol
table for the load and has a file extension of .SYM.
LINK's output
files are described in Chapter 4.

1.3

LINK'S OVERLAY FACILITY

If your program is larger than your available memory, you can use
LINK's overlay facility to make it fit in memory. To do this, you
define a tree structure for the program's modules. Then, at execution
time, only part of the tree is in memory at one time. This reduces
the amount of memory needed for execution.
See Chapter 5 for a
discussion of overlays.

1.4

LINK AND EXTENDED ADDRESSING

The KL Model B processor is capable of using an address space
consisting of 32 sections, each containing 512 pages. As of TOPS-10
Version 7.03, programs have been able to reference this expanded
address space.
For information on using extended addressing with a
specific programming language, consult the documentation for that
language.
To load a program into a particular section, use the appropriate
monitor command with the IUSE switch. Refer. to the TOPS-10 Operating
System Commands Manual for more information.
Use PSECTs to load a program into a nonzero section.
for information on loading PSECTs.

See Section

6.1

When loading a program that uses extended addressing, pay particular
attention to the use of l8-bit and 30-bit addresses. If a program
uses 30-bit addresses and you reference a 30-bit address as an l8-bit
address, LINK truncates the 30-bit address and notifies you with the
following message:
%LNKFTH Fullword value [symbol] truncated to halfword
LINK issues this warning if the truncation results in the loss of a
section number.
Refer to Appendix B for more information about this
message.
While writing an extended
restrictions in mind:

addressing

program,

keep

the

following

•

Programs that use overlays cannot use nonzero sections.

•

Programs should not store executable code into locations 0
through 17 of nonzero sections. However, you can store data
that is not executed in these locations. If you store data
in locations 0 through 17, use global addresses to reference
the
locations.
If
you
use
local
addresses,
ACs
(accumulators)
are
referenced instead.
In Section 1,
locations 0 through 17 refer to ACs.

LINK V6.0

1-3

April 1986

INTRODUCTION TO LINK
1.5

USING LINK

You have two ways to use LINK:
1.

You can use LINK automatically by means of the LOAD, EXECUTE,
or DEBUG system commands. This is the easiest and best way
to load many programs. Chapter 2 describes automatic use of
LINK.

You can run LINK directly by typing R LINK to the monitor.
This is necessary only for very large or complicated loads,
such as those involving overlays. Chapter 3 discusses direct
use of LINK.

1-4

April 1986

CHAPTER 2
USING LINK AUTOMATICALLY

The system commands
LOAD,
EXECUTE,
and
DEBUG
invoke
LINK
automatically.
Each of these commands uses a simple command string;
the system converts the string into more complicated LINK commands.
This discussion of the LOAD, EXECUTE,
and DEBUG commands does not
attempt to describe them completely. Only those switches applying
directly to loading will be discussed here.
For a
full discussion,
see the TOPS-IO Operating System Commands Manual.
These system commands invoke LINK:

2.1

•

The LOAD command uses LINK to load your object modules into
memory,
but does not execute the program.
Before loading,
your source files are compiled,
if
necessary;
this
compilation will occur if there are no object modules for the
specified source files, or if the object files are older than
their source files.

•

The EXECUTE command uses LINK to load your program, and then
executes the loaded program.
Before loading, your source
files are compiled, if necessary.

•

The DEBUG command works like the EXECUTE command, except that
your program is executed under the control of a debugging
program.
The debugging program that is loaded depends on the
type of program being loaded.
See the /TEST switch for a
list of languages.
The system uses the file extension to
determine the language in which the program is written.
Therefore, it is highly recommended that you use standard
file extensions when naming the files of your programs.
Standard file extensions are listed in the appropriate
Commands Manual for the operating system.

COMMAND FORMATS

The formats for the LOAD, EXECUTE, and DEBUG commands are the same.
Each can accept a list of input file specifications and switches.
The
format for these commands is:
.command/switches input-spec/switches, input-spec/switches, ...
Where the command is one of the three system commands (LOAD,
EXECUTE,
or DEBUG),
input-spec is the file specification of the program you
want to load, and the switches are any of the valid switches for
the
command.

2-1

USING LINK AUTOMATICALLY
If you separate the input file specifications with commas, each source
file will be compiled into a separate object file.
If you separate
the input file specifications with plus signs, they will be compiled
into a single object file.
Section 2.3 shows examples of using LINK automatically.

2.2

COMMAND SWITCHES

You can use switches with the LOAD, EXECUTE,
and DEBUG commands to
control LINK's loading.
Table 2-1 briefly describes some of the
command switches that apply to LINK.
Refer to the TOPS-IO Operatins
System Commands Manual for complete descriptions of the switches for
these commands.
Table 2-1
Switches for System Commands
Meaning

Switch

I
I

/COMPILE

Forces compilation of source files even
sufficiently recent REL file exists.

/DDT

This supersedes the default debugger
Loads DDT.
which
is usually based on the
selection,
file
in the command
extension of the first
string.

/DEBUG

Causes the
FORTRAN
debugging information.

/MAP

Produces a map file at the end of loading.
file shows all global symbols loaded.

/NOCOMPILE

Compiles source files only if their REL files
are older than the source files.
/NOCOMPILE is
the default.

/NODEBUG

Prevents the FORTRAN compiler
debugging information.

/NOSEARCH

Suspends the effect of an earlier global/SEARCH
switch.
This is the default action.

/SEARCH

Loads only the modules from the
specified
library file that satisfy global references in
the program.

compiler
to
generate
/NODEBUG is the default.

from

This

generating

You can use any LINK program switches with the system commands LOAD,
EXECUTE,
or DEBUG by using a special switch format.
This format
requires that you use a percent sign (%) instead of the usual slash
(/),
and that the entire switch specification be enclosed in double
quotation marks (").
For example, you can pass the /ERRORLEVEL switch
to LINK by using the command:
.EXECUTE MYPROG %"ERRORLEVEL:O"

2-2

USING LINK AUTOMATICALLY
Used directly with LINK, the command strings would include:

*MYPROG/ERRORLEVEL:O
If you give more than one switch in this format,
succeeding
within the quotation marks must have the usual slashes:

switches

.EXECUTE MYPROG%"ERRORLEVEL:O/SEGMENT:LOW"
LINK program switches are described in Section 3.2.

2.3

EXAMPLE OF USING LINK AUTOMATICALLY

For this example, the following program, named MYPROG.FOR, is used:
10

TYPE 10
FORMAT (' This is written by MYPROG')
STOP
END

The following example shows an interactive execution
using the EXECUTE command:

the

program

. EXECUTE MYPROG. FOR ~
FORTRAN:
MYPROG
MAIN.
LINK:
Loading
[LNKXCT MYPROG execution]
This is written by MYPROG.
CPU time 0.16
Elapsed time 0.28
EXIT

The following example shows how to load a program for debugging
the DEBUG command:
.DEBUG MYPROG.FOR~
FORTRAN:
MYPROG
MAIN.
LINK:
Loading
[LNKDEB FORDDT execution]
STARTING FORTRAN DDT
»START
This is written by MYPROG.
CPU time 0.16
Elapsed time 0.42
EXIT

2-3

using

CHAPTER 3
USING LINK DIRECTLY

If you have a loading task that cannot be handled conveniently by the
EXECUTE,
LOAD,
or DEBUG system commands (such as loading overlays or
PSECTs), you can load your program by using LINK directly.
To do
this,
you must already have compiled or assembled all required object
modules.
To use LINK directly, type R LINK to the system.
with an asterisk:

LINK

will

respond

carriage

.R LINK ~

*
Continue typing command strings,
return.
For example,

ending

each

one

with

.R LINK~
*/OVERLAY ~
*TEST/LINK: TEST ~
*
/NODE:TEST SPEXP/LINK:SPEXP~

*
A command string consists of file specifications and
switches.
You
can continue a command string to the next line by typing a hyphen
immediately before pressing carriage return;
LINK continues the line
by responding with a number sign (#).
For example,
.R LINK ~
*MYPROG , MYMAP /MAP /CONTENTS : ALL- G£D
#/ERRORLEVEL:O/LOG/LOGLEVEL:5~

*
The use of continuation lines is more efficient as the command scanner
must be invoked for every distinct command string.
You can include a comment on a command line by beginning the comment
with a semicolon;
the remaining text on the line is not processed by
LINK.
When LINK sees the end of the command string (a carriage return),
it
processes the entire string, then prints an asterisk to begin the next
line.
This processing continues until one of the following occurs:
1.

LINK finds a /GO switch in a
command string.
It then
completes loading and exits to system command level (if you
did not specify execution), or passes control to the loaded
program for execution.

3-1

USING LINK DIRECTLY

I
3.1

A fatal error occurs.
LINK prints an error message and exits
to system command level.

A /RUN switch is encountered.

Either /EXIT or

is encountered.

COMMAND STRING FORMAT

A LINK command string can contain file specifications, LINK switches,
and command scanner switches.
Command scanner switches are described
in Section 3.2.1.
LINK switches are described in Section 3.2.2.
Some LINK switches take output file specifications as arguments;
some
switches are suffixed to output file specifications. Other file
For example,
the following
specifications specify input files.
command string tells LINK to use an input file called MYREL.REL to
generate a saved output file called MYEXE.EXE:
*MYREL,MYEXE/SAVE/GO
LINK supplies the missing parts of the file
defaults.

specifications

from

its

DEFAULTS
For output files, the defaults are:

device

DSK:

file name

name of last module with start address or,
if none,
then nnnLNK where nnn is your job number with leading
zeros if necessary

extension

log file
map file
overlay file
plotter file
executable file
symbol file

directory

your current path, i.e.

You can change these
Section 3.2.2).

defaults

using

[30,5526,LINK,TEST]
the

/DEFAULT

switch

(see

You can have LINK read command strings from an indirect command file.
To do this, prefix an at-sign (@) to the command file specification.
For example, the following commands tell LINK to read all command
strings from the file LNKPRG.CCL.
(.CCL is the default file extension
for indirect command files, but if .CCL is not found,
.CMD will be
tried.) :
. R LINK0!D
*@LNKPRG0!D
3-2

USING LINK DIRECTLY
3.2

SWITCHES TO LINK

LINK's handling of files depends on your use of LINK switches.
There
are two sets of switches to LINK.
The first set of switches (command
scanner switches) are optional switches that define your
request to
the system command scanner.
These are described in Section 3.2.1.
The second set of switches are switches to LINK that you can use to
control and modify the linking and
loading process.
These are
described in Section 3.2.2.

3.2.1

Command Scanner Switches

The system SCAN module scans command lines for various system
programs, one of which is LINK.
You can include SCAN switches in your
command strings for LINK;
however, none of these switches is required
in order to run LINK.
The following SCAN switches are meaningful
to LINK.
The remaining
SCAN switches, which are listed in LINK's HELP file, are ignored by
LINK.
Like LINK switches, SCAN switches are preceded by a slash (I), and can
be abbreviated up to their first unique characters.
SCAN Switches Meaningful to LINK
Switch

Meaning

IESTIMATE:n

Reserves n 128-word disk
blocks
for
the
specified output file.
This does not work
globally, but only on the file for which it is
specified.
By
default,
disk
space
is
automatically allocated, as required, for
files
output
to
disk.
This
allocates
blocks
contiguously on the
disk,
thus
providing
improved access times.

IEXIT

Exits, but leaves LINK's core image in place.

IHELP:arg

Displays the HLP:LINK.HLP file.
Specifying
IHELP:SWITCHES types LINK and SCAN switches with
no explanations.

IMESSAGE:keyword

Displays messages in the format specified by
keyword.
The keywords and their meanings are:

INOOPTION

PREFIX

Displays only the message code
from SCAN or LINK which are of
the forms SCNxxx, or LNKxxx.

FIRST

Displays the prefix
short message.

and

CONTINUATION

Displays the prefix
longer message.

and

Ignores any LINK switches
DSK:SWITCH.INI[,]

3-3

found

the

file

I
I

USING LINK DIRECTLY
Switch

Meaning

/OPTION:name

Reads default LINK switches from the
file
SWITCH.INI,
on
the line that begins with
LINK:name.
If you use the /OPTION switch,
it
must appear in the first command string to LINK.

/PROTECTION:n

Assigns the 3-digit octal number n as
protection for the specified output file.

/RUN:file

Runs the specified program after loading is
finished.
This switch is ignored if you have
specified program execution.

/RUNOFFSET:n

Begins execution of the program given by
/RUN switch at the address n locations after
normal start address.
If you omit n,
default is 1.
If you omit /RUNOFFSET,
default is O.

/TMPFIL:file:"str"

Creates a TMPCOR file with the specified name.
The
name
must be a
3-character filename.
Usually, the string given in quotation marks is
a command string to be executed by the program
given in the /RUN switch when it is started one
location after
its normal start address (by
/RUNOFFSET:l) .

I
I
3.2.2

the

the
the
the
the

Link Switches

This section lists the switches that may be used to instruct LINK to
take special action while loading your programs.
The switches are
described in this section in alphabetical order, and for each switch
the following information is shown, if appropriate:
FORMAT
FUNCTION
EXAMPLES
OPTIONAL NOTATIONS
RELATED SWITCHES
Switches can be abbreviated to save typing.
However, in most cases,
the switch must include enough characters to make it unique from other
switches.
For example, the switch /NOSYMBOL cannot be abbreviated to
/NOSY,
because this result in a conflict with the switch /NOSYSLIB.
However, /NOSYM is a unique set of characters, and thus is a
legal
abbreviation for /NOSYMBOL.

Certain switches that can be abbreviated to a single letter are:
/D for
/E for
/G for
/Hfor
/L for
/M for
/N for
/S for
/T for
/U for
/V for

/DEBUG
/EXECUTE
/GO
/HELP
/LOCALS
/MAP
/NOLOCAL
/SEARCH
/TEST
/UNDEFINE
/VERSION

3-4

USING LINK DIRECTLY
Many switches accept a value that may be specified in decimal
is the default)
or octal.
If the value can be specified in
this is noted
in the OPTIONAL NOTATIONS section of the
description.
To specify an octal value, type a number sign (#)
the octal number.
For example, /ARSIZE:39 can be specified
in
as /ARSIZE:#47.

(which
octal,
switch
before
octal

Some switches accept a value that specifies an amount of memory area.
This value is interpreted as the number of pages,
by default.
However, this value may be specified as nK,
where n IS the number
l024-word blocks of memory (lK=2P).
Where this is valid, it is noted
in the OPTIONAL NOTATIONS section of the switch description.
Some
switches can be used either
locally or globally (in particular,
/LOCALS,
/NOLOCAL,
/NOSTART,
/SEGMENT,
/INCLUDE,
/ONLY,
/SEARCH,
/START and /NOSEARCH).
This means that if the switch is suffixed to a
file specification, it applies only to that file;
if it is not
suffixed to a file specification, it applies to the files that follow
on that command line.
For example, in the following command strings
/SEARCH is used both locally and globally:
1.

*FILEl,FILE2/SEARCH,FILE3

*FILE4,/SEARCH FILE5,FILE6

In the first line, /SEARCH is suffixed to the file specification
FILE2;
only that file is loaded in search mode.
In the second line,
/SEARCH is not suffixed to a file specification;
all
the remaining
files named in the command string are to be searched.
In general, a switch used globally is disabled at the end of its
command string, unless it is overridden by another switch.
The second
switch, if used locally, will override the first only for
the
local
file.
If the second switch is used globally, it will persist for the
following files.
For example, in the following command string,
a
globally-used switch (/SEARCH) is overridden by a locally used switch:
*/SEARCH FILEl,FILE2/NOSEARCH,FILE3
In this command string, FILEI and FILE3 will be loaded in search mode,
but FILE2 will be loaded normally.
NOTE
The effects of a global
switch on the
same line as a /GO switch persist beyond
the /GO switch and apply to any modules
loaded
during
library
searches.
However, for certain languages default
switches
may override user-specified
global switches.
The following pages contain the
listed in alphabetical order.

switches

3-5

and

their

descriptions,

I
I
I

USING LINK DIRECTLY
/ARSIZE

FORMAT

/ARSIZE:n
Where n is a positive decimal integer.

FUNCTION

Sets the size of the overlay
handler's
table
of
multiply-defined global symbols.
Use this switch if you
have received LNKARL, LNKTMA, and LNKABT messages in a
previous attempt to load your program.
These messages
will give instructions for the argument to the /ARSIZE
switch.

EXAMPLES

*/ARSIZE:39 G!D

*
Allocates 39 words for the multiply-defined global
table in each link of an overlay structure.
OPTIONAL
NOTATIONS

You can specify the table size in octal.

3-6

symbol

USING LINK DIRECTLY
/BACKSPACE

FORMAT

/BACKSPACE:n
Where n is a positive decimal integer.

FUNCTION

Backspaces over n files on the current tape device.
switch is ignored for non-tape devices.)

EXAMPLES

*MTAO: /BACKSPACE: 3 ~

*
Backspaces magtape MTAO: by three files.
OPTIONAL
NOTATIONS

If you omit n, it defaults to 1.

RELATED
SWITCHES

/MTAPE, /REWIND, /SKIP, /UNLOAD

3-7

(The

USING LINK DIRECTLY
/COMMON

FOR1~AT

/COMMON:name:n
Where name
characters.

six

SIXBIT-compatible

ASCII

n = a positive decimal integer.
FUNCTION

Allocates n words of labeled COMMON storage for FORTRAN
and FORTRAN-compatible programs.
The COMMON label is a
name, which becomes defined as a global symbol.
For unlabeled COMMON storage, use .COMM.
simply omit the name.

as the name,

You cannot expand a given COMMON area during loading.
If
your program modules define a given COMMON area to have
different sizes, the module giving the largest definition
must be loaded first.
If the /COMMON switch gives the
largest definition, it must precede the loading of the
modules.
EXAMPLES

*/COMMON:A: 1000 G!D

*
Creates a labeled COMMON area of 1000 words.
*/COMMON: .COMM.: 1000 ~

*
Creates an unlabeled COMMON area of 1000 words.
*/COMMON:: 1000 G!D

*
Creates an unlabeled COMMON area of 1000 words.

OPTIONAL
NOTATIONS

You can specify the number of words in octal.

RELATED
SWITCHES

/PSCOMMON

LINK V6 .. 0

3-8

April 1986

USING LINK DIRECTLY
/CONTENTS

FORMAT

/CONTENTS: (keyword, ... ,keyword)

FUNCTION

Each keyword gives a symbol type to be included in the map
file
if the file is generated. To generate the map file,
use the /MAP switch.
The keywords ALL, NONE, and DEFAULT reset all symbol
types.
Otherwise, using the /CONTENTS switch resets only
those symbol types specified by keywords.
In
the
following list of keywords, the defaults are in boldface:
ABSOLUTE
ALL
COMMON
DEFAULT
ENTRY
GLOBAL
LOCALS

NOABSOLUTE
NOCOMMON
NOENTRY
NOGLOBAL
NOLOCAL
NONE
NORELOCATABLE
NOUNDEFINED
NOZERO

RELOCATABLE
UNDEFINED
ZERO

I~clude absolute symbols.
Include all symbols.
Include COMMON symbols.
Reset to LINK's defaults.
Include entry-name symbols.
Include global symbols.
local
Include local symbols.
The
symbols cannot be included in the map
file unless the /LOCALS switch is also
given.
Exclude absolute symbols.
Exclude COMMON symbols.
Exclude entry-name symbols.
Exclude global symbols.
Exclude local symbols.
Exclude all symbols.
Exclude relocatable symbols.
Exclude undefined symbols.
Exclude
symbols
in
zero-length
programs.
(a
zero-length program
contains no code or data;
it contains
only
symbol
definitions,
e.g.,
JOBDAT. )
Include relocatable symbols.
Include undefined symbols.
Include
symbols
in
zero-length
programs.

Only those symbols that satisfy all conditions in the
keyword list will appear in the .MAP file.
For example,
if both the NOGLOBAL and RELOCATABLE settings are in
force, all global symbols are excluded regardless of their
relocatabilit.y.
EXAMPLES

*/CONTENTS: (NOCOMMON,NOENTRY) ~

*
Excludes COMMON and entry-name symbols.

* /CONTENTS : ALL ~

*
Includes all symbols.
OPTIONAL
NOTATIONS

You can omit parentheses if you give only one keyword.

RELATED
SWITCHES

/MAP
3-9

USING LINK DIRECTLY
/CORE

FORMAT

/COFE:nP
Where n is a positive decimal integer.

FUNCTION

The
Gives the initial low segment core size for LINK.
core size given with /CORE should not be larger than that
given with the /MAXCOR switch;
if it is not,
the core
will be allocated initially, but the first time LINK
expands core size, the allocation will be reduced to the
size given by /MAXCOR.

EXAMPLES

* /CORE : 1 7P G!D
*

Allocates l7P (lP=5l2 words) of core for the
segment.

initial

OPTIONAL
NOTATIONS

You can specify the core size in octal.
You can also specify the argument in K instead of P.

RELATED
SWITCHES

/FRECOR, /MAXCOR, /RUNCOR

3-10

low

USING LINK DIRECTLY
/COUNTERS

FORMAT

/COUNTERS

FUNCTION

Displays information about relocation counters on the
terminal.
A relocation counter is an address counter that
LINK uses while loading relocatable code.
/COUNTERS returns the name, initial value, current value,
and limit value of each counter. /COUNTERS first prints
the following header:
Reloc. ctr.

initial value

current value

limit value

where:
Reloc. ctr.

gives the name of relocation counter.

initial value

is the origin of the relocation counter.

current value

is the address of the next free location
after the relocation counter has been
loaded.

limit value

is an upper bound that you set using
/LIMIT or that LINK sets by default for
the relocation counter.
This
upper
bound defines a point the relocation
counter should not load beyond.
If
/LIMIT is used and the counter loads
beyond
this
bound,
LINK
returns
messages.
See
/LIMIT
for
more
information.

/COUNTERS may be used to determine the size of overlays
when loading programs that might be too for the allocated
memory space. Refer to Section 5.4 for more information.
You can also use /COUNTERS to determine the size of PSECTs
when loading extended addressing programs or programs that
use PSECTs to conserve memory space. Refer to Chapter 6.
EXAMPLES

The following examples illustrate
displays.

the

various

The following display results from loading a
does not contain code.

/COUNTERS

module

that

*/COUNTERS GD
[LNKRLC No relocation counters set]

*
The following display results from loading
code.

only

absolute

*ABCODE/COUNTERS GD
[LNKRLC No relocation counters set
Absolute code loaded]

LINK V6.0

3-11

April 1986

USING LINK DIRECTLY
The following display
code.

results

from

only

PSECT

*PSCODE/COUNTERS ~
[LNKRLC Reloc. ctr.
PSCODE

initial value
20

current vaLue
25

limit value
1000000]

*
The following display results from loading
contains both absolute and PSECT code.
*MIXED/COUNTERS ~
initial value
[LNKRLC Reloc. ctr.
PSECTA
1400000
2500000
PSECTB
3600000
PSECTC
Absolute code loaded]

code

current value
1400001
2500001
3600001

that

limit value
4000000
4000000
4000000

*
The following display
formatted code.

results

from

two-segment

*TWOPRT/COUNTERS~

[LNKRLC Reloc. ctr.
.LOW.
.HIGH.

initial value

400000

current value
1642
400753

limit value
1000000
1000000]

*
RELATED
SWITCHES

LINK V6.0

/NEWPAGE, /SET, /LIMIT

3-12

April 1986

USING LINK DIRECTLY
/CPU

FORMAT

/CPU:keyword
Keyword:

KAl0
KIl0
KLl0
KSl0

FUNCTION

This switch is used to override LINK's handling of the
processor
information found
in the
.REL files being
loaded.
(See the description of the type 6 block in
Appendix A).
Ordinarily LINK prints a warning if all .REL
files being loaded together do not have
identical CPU
types.
This switch can be used either to make LINK flag
certain modules built for a specific CPU type
(by
specifying all but that CPU type as keywords to /CPU) or
to suppress LINK's warning message (by specifying all the
CPU types associated with the .REL files being loaded).

EXAMPLE

*/CPU:KI10<RET)

*
Will cause LINK to
issue the %LNKCCD message
modules with the KLl0 CPU type are encountered.
OPTIONAL
NOTATIONS

any

/CPU: (keyword,keyword)

3-12.1

April 1986

USING LINK DIRECTLY

THIS PAGE INTENTIONALLY LEFT BLANK.

3-12.2

April 1986

USING LINK DIRECTLY
/DDEBUG

FORMAT

/DDEBUG:keyword

FUNCTION

Specifies a default debugging program to be loaded if
/DEBUG or /TEST switch appears without an argument.
The permitted keywords and
specify are listed below.
are supported by DIGITAL.
ALGDDT
ALGOL
COBDDT
COBOL
DDT
FAIL
FORDDT
FORTRAN
MACRO
PASCAL
PASDDT
SAIL
SDDT
SIMDDT
SIMULA

EXAMPLES

the

the debugging programs they
Only those printed in boldface

Specifies ALGDDT as the default.
Specifies ALGDDT as the default.
Specifies COBDDT as the default.
Specifies COBDDT as the default.
Specifies DDT as the default.
Specifies SDDT as the default.
Specifies FORDDT as the default.
Specifies FORDDT as the default.
Specifies DDT as the default.
Specifies PASDDT as the default.
Specifies PASDDT as the default.
Specifies ~he SAIL debugger as the default.
Specifies the SAIL debugger as the default.
Specifies SIMDDT as the default.
Specifies SIMDDT as the default.

*/DDEBUG:FORTRAN ~

*
Specifies FORDDT as the default debugging program for
/DEBUG 0 r /TE&T swi tch.
RELATED
SWITCHES

/DEBUG, /TEST

3-13

the

USING LINK DIRECTLY
/DEBUG

FORMAT

/DEBUG:keyword

FUNCTION

Requests loading of a debugging program and sets the start
address for execution as the normal start address of the
debugging program.
The /DEBUG switch also sets the
/EXECUTE switch because it is assumed that the program is
to be executed.
The /GO switch is still required to end
loading and begin execution.
The /DEBUG switch turns on the /LOCALS switch for
the
remainder of the load.
You can override this by using the
/NOLOCAL switch,
but the override lasts only during
processing of the current command string.
Local symbols for the debugging program itself
loaded.

are

never

If debugging overlaid programs, you must specify /DEBUG
when loading the root node.
(Refer to Section 5.4 for
more information.)
The permitted keywords and the programs they load
listed
below.
Only those printed
in boldface
supported by DIGITAL.
ALGDDT
ALGOL
COBDDT
COBOL
DDT
FAIL
FORDDT
FORTRAN
MACRO
PASCAL
PASDDT
SAIL
SDDT
SIMDDT
SIMULA

are
are

Loads ALGDDT.
Loads ALGDDT.
Loads COBDDT.
Loads COBDDT.
Loads DDT.
Loads SDDT.
Loads FORDDT.
Loads FORDDT.
Loads DDT.
Loads PASDDT.
Loads PASDDT.
Loads the SAIL debugger.
Loads the SAIL debugger.
Loads SIMDDT.
Loads SIMDDT.

If you give no keyword with /DEBUG, the default is either
DDT or the debugging program specified by the /DDEBUG
swi tch.
EXAMPLES

*/DEBUG:DDT ~

*
Loads DDT, sets the /EXECUTE switch,
and
the execution will be controlled by DDT.
OPTIONAL
NOTATIONS

Abbreviate /DEBUG to /D.

RELATED
SWITCHES

/DDEBUG, /TEST

3-14

specifies

that

USING LINK DIRECTLY
/DEFAULT

FORMAT

/DEFAULT:keyword filespec
filespec/DEFAULT:keyword

FUNCTION

Changes default specifications for input or output files.
The defaults specified remain in effect until changed by
another /DEFAULT switch.

The keywords allowed are:
INPUT

Specifies the defaults for
specifications.

input

file

OUTPUT

Specifies the defaults for output
specifications.

file

For input files, the initial defaults are:
device
extension
directory

DSK:
REL
User's connected directory

For output files, the initial defaults are:
device
filename
directory
EXAMPLES

DSK:
Name of main program
User's connected directory

* /DEFAULT: INPUT . BIN C@

*
Resets input file default extension to BIN.
*/DEFAULT:OUTPUT MTAO: ~

*
Resets output file default device to MTAO:.
OPTIONAL
NOTATIONS

If you omit the keyword, INPUT is assumed.

3-15

USING LINK DIRECTLY
/DEFINE

FORMAT

/DEFINE: (symbol:value, ... ,symbol:value)

FUNCTION

Assigns each symbol the decimal value following it.
This
causes them to be global symbols.
You can use the
/UNDEFINED switch to get a list of any undefined symbols,
and then define them with /DEFINE.
Defining an already defined symbol with /DEFINE
an error message.

EXAMPLES

generates

* /UNDEFINED ~
[LNKUGS
2 UNDEFINED GLOBAL SYMBOLS]
A
400123
IGOR
402017
*/DEFINE: (A:59l,IGOR:l) ~

*
Gives the decimal
respectively.

values

591

and

IGOR,

NOTATIONS

You can give the value in octal by typing # before the
value.
You can omit the parentheses if you define only one
symbol.
Specifying /DEFINE:FOO:BAR will define FOO to
have the value of BAR if BA~ is already defined.

RELATED
SWITCHES

/UNDEFINED, /VALUE

OPTIONAL

3-16

USING LINK DIRECTLY
/ENTRY

FORMAT

/ENTRY

FUNCTION

Requests terminal typeout (in octal)
of all entry name
symbols loaded so far.
Each entry name symbol will have
been defined by an ENTRY statement
(MACRO,
FORTRAN,
or
BLISS),
a FUNCTION statement
(FORTRAN),
a SUBROUTINE
statement (FORTRAN, or COBOL), or a PROCEDURE declaration
(ALGOL) .
If you are using the overlay facility,
/ENTRY requests
only the entry name symbols for the current link.

EXAMPLES

*/ENTRY ~
[LNKLSS LIBRARY SEARCH SYMBOLS
SQRT.
3456

*
RELATED
SWITCHES

/NOENTRY

3-17

(ENTRY POINTS)]

USING LINK DIRECTLY
/ERRORLEVEL

FORMAT

/ERRORLEVEL:n

FUNCTION

Suppresses terminal typeout of LINK messages with message
level n and less, where n is a decimal number between 0
and 30 inclusive.
You cannot suppress level 31 messages.
LINK's default is /ERRORLEVEL:IO.
See Appendix B for the level of each LINK message.

EXAMPLES

*/ERRORLEVEL: 10 ~

*
Suppresses all messages of level 10 and less.
*/ERRORLEVEL:O ~

*
Permits typeout of all messages.

RELATED
SWITCHES

/VERBOSITY, /MESSAGE

3-18

USING LINK DIRECTLY
/EXCLUDE

FORMAT

/EXCLUDE: (subroutine, .•. ,subroutine)

FUNCTION

Prevents loading of the specified modules from the current
file even if they are required to resolve global symbol
references.
You can use the /EXCLUDE switch for
any of
the following purposes:

EXAMPLES

•

If a library has several modules with the same search
symbols,
you can select the module you want by
excluding the others.

•

You can prevent
modules
from
giving
multiple
definitions of a symbol by selectively excluding one
or more of them.

•

you can delay
In defining an overlay structure,
loading of a module until a later link by excluding
it.

*/SEARCH LIBFIL.REL/EXCLUDE: (MODI,MOD2) ~

*
Searches LIBFIL as a library but prevents loading of
and MOD2 even if they are referenced.

MODI

OPTIONAL
NOTATIONS

You can omit the
module.

one

RELATED
SWITCHES

/INCLUDE

parentheses

3-19

you

specify

only

USING LINK DIRECTLY
/EXECUTE

FORMAT

/EXECUTE

FUNCTION

Tells LINK that the loaded program is to be executed
Loading continues
beginning at its normal start addre£s.
until a /GO switch is found.
The /EXECUTE and IDEBUG switches are mutually exclusive.

EXAMPLES

*/EXECUTE ~

*
OPTIONAL
NOTATIONS

You can abbreviate IEXECUTE to IE.

RELATED
SWITCHES

IDEBUG, IGO, IRUN, ITEST

3-20

USING LINK DIRECTLY
/FRECOR'

FORMAT

/FRECOR:nK
Where n is a positive decimal integer.

FUNCTION

Requires LINK to maintain a minimum amount of free memory
after any expansions.
LINK's default free memory is 4K.
If you use the /FRECOR:nK switch, LINK computes n times
1024 words and maintains the resulting number of words of
free memory, if possible.
If the modules to be loaded are quite large, a
amount of free memory avoids some moving of areas.

larger

The following areas may be expanded during loading:
1.

ALGOL symbol information (AS).

Bound global symbols (BG).

Dynamic area (DY).

Fixup area (FX).

Global symbol tables (GS).

User's high segment code (HC).

User's low segment code (LC).

Local symbol tables (LS).

Relocation tables (RT).

10.

Argument typechecking (AT)

Each of these areas has a lower bound, an actual upper
bound, and a maximum upper bound. LINK normally maintains
space between the actual and maximum upper bounds for each
area.
The total of these areas is at least the space
given by the /FRECOR switch, if possible.
If the low segment code area exceeds the limit set by the
user
(with /MAXCOR)
or by the system (CORMAX), LINK
recovers free core by concatenating these free areas.
When all this recovered space is used, one or more of the
areas overflows to disk, and free core is no longer
maintained.
EXAMPLES

*/FRECOR: 7K ~
*
Maintains 7K of free core, if possible.

OPTIONAL
NOTATIONS

You can specify the free core in octal.

RELATED
SWITCHES

/CORE, /MAXCOR, /RUNCOR

LINK V6.0

3-21

April 1986

USING LINK DIRECTLY
/GO

FORMAT

/GO

FUNCTION

Ends loading after the current module.
LINK then performs
any required library searches, generates any required
output files, and does one of the following:

EXAMPLES

•

Begins execution at the normal start address
loaded program (if you used /EXECUTE).

•

Begins execution at the start address of the debugging
program
(if you used /DEBUG,
or both /TEST and
/EXECUTE) .

•

Exits to
swi tch) .

the

monitor

(if

you

used

the

execution

*MYPROG/EXECUTE/GO ~
[LNKXCT

MYPROG EXECUTION]

Begins execution of the loaded program at its normal start
address.
*MYPROG/DEBUG/GO ~
[LNKDEB DDT EXECUTION]
Begins execution of the loaded program at the normal start
address of DDT.
OPTIONAL
NOTATIONS

Abbreviate /GO to /G.

RELATED
SWITCHES

/DEBUG, /EXECUTE, /RUN, /TEST

3-22

USING LINK DIRECTLY
/HASHSIZE

FORMAT

/HASHSIZE:n
Where n is a positive decimal integer.

FUNCTION

Gives a minimum for the initial size of the global
symbol
table.
LINK selects a prime number larger than n for the
initial size.
If you know that you will need a
large global
symbol
table, you can save time and space by allocating space for
it with /HASHSIZE.
You should give a hash size at least
10 percent larger than the number of global symbols in the
table.
If LINK gives the message [LNKRGS Rehashing Global Symbol
Table]
during a load, you should use the /HASHSIZE switch
for future loads of the same program.
The minimum hash
size for loading a program appears in the header lines of
the map file.
The default hash size
(initially 251 decimal).

EXAMPLES

LINK

assembly

* /HASHSIZE: 1000 ~
*
Sets the hash size to the prime number 1021.

3-23

parameter

USING LINK DIRECTLY
/INCLUDE

FORMAT

/INCLUDE: (module, ... ,module)

FUNCTION

Specifies modules to be loaded regardless
requests for them.

any

global

In library search mode,
an /INCLUDE switch requests
loading of the specified modules.
If the switch is
associated with a file, the request is cleared after
that
file
is searched.
If not, the request persists until the
modules are found.
When LINK is not in library search mode,
the /INCLUDE
switch associated with a
file
requests that only the
specified modules be loaded, and the request
is cleared
after
that file
is processed.
An /INCLUDE switch not
associated with a file requests loading of the specified
modules,
and the request persists until the modules are
found.
You can use /INCLUDE in an overlay load to force a module
to be loaded in an ancestor link common to successor links
that reference that module.
This makes the
module
available to all links that are successors to its link.
EXAMPLES

*/SEARCH LIBI/INCLUDE: (MODI,MOD2)

*
Searches LIBI and loads MODI and MOD2 even if they are not
referenced.
OPTIONAL
NOTATIONS

You can omit the
module.

RELATED
SWITCHES

/EXCLUDE, /NOINCLUDE, /MISSING

parentheses

3-24

you

specify

only

one

USING LINK DIRECTLY
/LIMIT

FORMAT

/LIMIT:psect:address

FUNCTION

Allows you to specify an upper bound for a specific PSECT.
In the format description, psect should be the PSECT name,
which has been defined with either the /SET switch or
in
one of the modules already loaded.
Address should be the
upper bound address of the specified PSECT,
expressed
in
either numeric or symbolic form.
This address should be
one greater than the highest location which may be loaded
in the PSECT.
If the PSECT grows beyond the address specified
in the
/LIMIT switch, LINK will send a warning to your terminal,
but will continue to process input files and to load code.
The warning message will take the following form:
%LNKPEL PSECT <psect> exceeded limit of <address>
No chained references will be
resolved,
and LINK will
suppress program execution, producing the following fatal
error:
?LNKCFS Chained fixups have been suppressed
This action prevents unintended PSECT overlays.
PSECT
overlays can cause loops and other unpredictable behavior,
because LINK uses address relocation chains
in the user
image that is being built.

EXAMPLE

*TESTI ~
* /COUNTERS G!D
[LNKRLC RELOC. CTF.
.LOW.
Q
R

INITIAL VALUE

1000
4500

CURRENT VALUE
140
4000
10500

LIMIT VALUE
1000000
1000000
1000000]

*/LIMIT:Q: 4000 ~
*TEST2 G!D
%LNKPEL PSECT Q EXCEEDED LIMIT OF 4000
DETECTED IN MODULE .MAIN FROM FILE DSK:TEST2.REL
* /COUNTERS G!D
CURRENT VALUE
LIMIT VALUE
[LNKRLC RELOC. CTR.
INITIAL VALUE
.LOW.
o
140
1000000
Q
4000
1000
5000
R
4500
10500
1000000]
*TEST/SAVE/GO @)
%LNKPOV PSECTS RAND Q OVERLAP FROM ADDRESS 4500 TO 5000
?LNKCFS CHAINED FIXUPS HAVE BEEN SUPPRESSED

In this example, a program named TESTl, which contains two
PSECTs,
is loaded.
The PSECTs are named Q and R.
After
TESTI is loaded, the /COUNTERS switch shows that the upper
bound of PSECT Q is 4000.

3-25

USING LINK DIRECTLY
The /LIMIT switch is used to limit PSECT Q to 4000.
A second program, TEST2, also requires storage for PSECT
Q.
Therefore, when TEST2
is loaded,
LINK produces a
warning to the effect that the limit that was set haS been
exceeded.
The /COUNTERS switch
shows that PSECT Q now
requires an upper bound of 5000.
When the programs are started (with /GO) ,
LINK produces
the POV warning message and the CFS fatal error message.
RELATED
SWITCH

/COUNTER

OPTIONAL
NOTATIONS

A defined global symbol can be used to specify
the limit value, e.g., /LIMIT:FOO:BAR.

3-26

USING LINK DIRECTLY
/LINK

FORMAT

/LINK:name

Where name is up to 6 RADIX-50 compatible characters.
FUNCTION

Directs LINK to give the specified name to the current
core image and outputs the core image to the overlay file.
/LINK is used to close an overlay link.
LINK first
performs any required library searches and assigns a
number to the link.
For a discussion of overlay structures, see Chapter 5.
The current core image has all modules loaded since
beginning of the load or since the last /LINK switch.

EXAMPLES

the

*SPEXP/LINK:ALPHA~

*
Loads module SPEXP and outputs the
overlay file as a link called ALPHA.

core

image

OPTIONAL
NOTATIONS

If you omit the link name, LINK uses only its assigned
number.

RELATED
SWITCH

/NODE

3-27

the

USING LINK DIRECTLY
/LOCALS

FORMAT

/LOCALS

FUNCTION

Includes local symbols from a module in the symbol
table.
LINK does not need these tables, but you may want them for
debugging.
To have the symbol table included in a program
use the /SYMSEG switch.
The /LOCALS and /NOLOCAL switches may be used
locally or globally.
If the switch is suffixed to
specification, it applies only to that file;
if it
suffixed to a
file specification,
it applies
following files in the same command line.

EXAMPLES

either
a file
is not
to all

*/SYMSEG ~
*/LOCALS A,B/NOLOCAL,C,/NOLOCAL D ~

*
Loads A with local symbols, B without local
symbols,
with local symbols, and D without local symbols.
OPTIONAL
NOTATIONS

You can abbreviate /LOCALS to /L.

RELATED
SWITCHES

/NOLOCAL, /SYMSEG

3-28

USING LINK DIRECTLY
/LOG

FORMAT

logfilespec/LOG

FUNCTION

Specifies a file
specification for
the log file
(see
Section 4.2.2).
Any LINK messages output before the /LOG
switch is encountered are not entered in the log file.

EXAMPLES

*LOGFI L/LOG G!D

*
Specifies the file DSK:LOGFIL.LOG in the user's directory.
*TTY: /LOG G!D

*
Directs log messages to the user's terminal.
OPTIONAL
NOTATIONS

You can omit all or part of the logfilespec.
The defaults are:
device
filename
extension
directory

DSK:
name of main program
LOG
your logged-in directory

You can change the defaults using the /DEFAULT switch.
RELATED
SWITCHES

/LOGLEVEL

3-29

USIN~

LINK DIRECTLY

/LOGLEVEL

FORMAT

/LOGLEVEL:n

FUNCTION

Suppresses logging of LINK messages with level n and less,
where n is a decimal number between 0 and 30 inclusive.
You cannot suppress level 31 messages.
See Appendix B for the level of each LINK message.
The default is /LOGLEVEL:IO.

EXAMPLES

* /LOGLEVEL: 0 G!D
*
Logs all messages.

RELATED
SWITCHES

/ERRORLEVEL, /LOG

3-30

USING LINK DIRECTLY
/MAP

FORMAT

mapfilespec/MAP:keyword

FUNCTION

Specifies a file specification for
the map output file
(see
Section
4.2).
The contents of the file are
determined by the /CONTENTS switch or its defaults.
Permitted keywords and their meanings are:

EXAMPLES

END

Produces a map file at the end of the
load.
This is the default if you omit the
keyword.

ERROR

error
if a fatal
Produces a map file
Any modules loaded after this
occurs.
To
switch will not appear
in the log.
is generated,
ensure that a
.MAP file
specify this switch before the loading of
.REL files.

NOW

Library
Produces a map file immediately.
searches will not have been performed
unless forced.

*MAPF I L/MAP : END ~

*
Generates a map in the file DSK:MAPFIL.MAP
area at the end of loading.
OPTIONAL
NOTATIONS

your

You can omit all or part of the mapfilespec.
The defaults are:
device
filename
extension
directory

DSK:
name of main program
MAP
user's connected directory

You can change the defaults using the /DEFAULT switch.
You can abbreviate /MAP to /M.
RELATED
SWITCHES

/CONTENTS

3-31

disk

USING LINK DIRECTLY
/MAXCOR

FORMAT

/MAXCOR:nP
Where n is a positive decimal integer.

FUNCTION

Requires LINK to overflow low segment code larger than n
pages to disk.
The disk overflow may contain symbol
areas, low segment code, and high segment code.
If you specify MAXCOR smaller than the memory already
used,
disk overflow occurs at the next expansion and
memory is reduced to your specified MAXCOR.
If you specify MAXCOR smaller
than
LINK's
minimum
requirement, you will get an error message.
You must then
use another /MAXCOR switch to enlarge the core.

EXAMPLES

* /MAXCOR: 3 OP G!D
*
Specifies a maximum core use of 30 pages (lP=5l2 words).

OPTIONAL
NOTATIONS

You can specify the core in octal.
You can specify the switch argument as K instead of P.

RELATED
SWITCHES

JCORE, jFRECOR, jRUNCOR

3-32

USING LINK DIRECTLY
/MAXNODE

FORMAT

/MAXNODE:n
Where n is a positive decimal integer.

FUNCTION

Specifies the number of links to be defined when the
LINK will
overlayed program requires more than 256 links.
certain
allocate extra space in the OVL file
for
fixed-length tables based on the number of links specified
with this switch.
Note that this switch must be placed after
the /OVERLAY
switch and
it must precede the first /NODE switch in the
set of commands to LINK.

EXAMPLES

*TEST/OVERLAY/MAXNODE: 500 ~

*
Reserves space for 500 defined links.
discussion on overlays.
RELATED
SWITCHES

/OVERLAY

3-33

See Chapter 5 for a

USING LINK DIRECTLY
/MISSING

FORMAT

/MISSING

FUNCTION

Requests terminal typeout of modules requested
/INCLUDE switch that have not yet been loaded.

EXAMPLES

*MYPROG ~
* /SEARCH/INCLUDE: (MODI, MOD2) LIBI ~
*/MISSING ~
[LNKIMM I INCLUDED MODULE MISSING]
*LIB2/INCLUDE: (MOD2) Cili)
*/MISSING ~
[LNKIMM NO INCLUDED MODULES MISSING]

with

the

*
This example shows the use of /MISSING to see if all the
required modules have been loaded.
The module MOD2 was
not yet loaded, and it was in LIB2.
In response to the first use of the switch, LINK indicated
that one necessary module was missing.
After the missing
module was included (module named LIB2),
the switch is
used again.
LINK responded to the second use of the
switch by indicating that all necessary modules were
present.

RELATED
SWITCHES

/INCLUDE, /UNDEFINED

3-34

USING LINK DIRECTLY
/MTAPE

FORMAT

/MTAPE:keyword

FUNCTION

Specifies tape operations to be performed on the current'
device.
(A tape device remains current only until
end-of-line or until another
device
is
specified,
whichever is earlier.)
The switch is
ignored
if the
current device is not a tape.
The operation is performed immediately if /MTAPE is given
with an input file or with an already initialized output
file.
Otherwise, the operation is performed when the
output file is initialized.
The valid keywords and the operations they specify are:
MTBLK
MTBSF
MTBSR
MTDEC
MTEOF
MTEOT
MTIND
MTREW
MTSKF
MTSKR
MTUNL
MTWAT

EXAMPLES

Writes 3 inches of blank tape.
Backspaces one file.
Backspaces one record.
Initializes
DIGITAL-compatible
9-channel
tape.
writes an end-of-file mark.
Spaces to logical end-of-tape.
Initializes
industry-compatible
9-channel
tape.
Rewinds tape to the load point (BOT).
Skips one file.
Skips one record.
Rewinds and unloads tape.
Waits for tape I/O to finish.

*MTAO : /MTAPE : MTEOT ~
*MTAO : /MAP: NOW ~

*
Spaces to logical end-of-tape on MTAO:
file.
RELATED
SWITCHES

/BACKSPACE, /REWIND, /SKIP, /UNLOAD

3-35

and writes

map

USING LINK DIRECTLY
/NEWPAGE

FORMAT

/NEWPAGE:keyword

FUNCTION

Sets the relocation counter to the first word of the next
page.
If the counter
is already at a new page, this
switch is ignored.
The permitted keywords and their relocation counters are:

EXAMPLES

LOW

Resets the low-segment counter to new page.
If you omit the keyword, this is the default.

HIGH

Resets the high-segment counter to new page.

*/NEWPAGE:HIGH ~
*SUBRI G!D
* /NEWPAGE: LOW ~
*SUBR2C@

*
Sets the high-segment counter to a new page, loads SUBRl,
sets the low-segment counter to a new page, and loads
SUBR2.
Note that SUBRI and SUBR2 are not necessarily
loaded into the high and low segments respectively;
the
/NEWPAGE switch sets a counter, but does not force
the
next loaded module into the specified segment.

RELATED
SWITCHES

/SET, /COUNTER

3-36

USING LINK DIRECTLY
/NODE

FORMAT

/NODE:argument

FUNCTION

Opens an overlay link.
/NODE places LINK's relocation
counter at the end of a previously defined link in an
overlay structure, which becomes the immediate ancestor to
the next link defined.
(For a discussion of overlay
structures, see Chapter 5.)
The /NODE switch must precede any modules to be placed
the new link.

Three kinds of arguments are permitted:
A name given with a previous /LINK switch.
LINK will
• place
the relocation counter at the end of the
specified link.
•

A negative number
the current path.

(-n).

LINK backs up n

links

along

•

A positive number n or O.
LINK begins further loading
at the end of link number n.
You can use 0 to begin
loading at the root link.

NOTE
It is recommended that you use a link name
(or 0
for
the root link) rather than a nonzero number.
This is because a change in commands defining an
overlay may change some of the link numbers.
EXAMPLES

For examples defining overlay structures, see Chapter 5.

RELATED
SWITCHES

/LINK, /OVERLAY, /PLOT

3-37

USING LINK DIRECTLY
/NOENTRY

FORMAT

/NOENTRY: (symbol,symbol, ... )

FUNCTION

Deletes entry name symbols from LINK's overhead tables
when loading overlays, thereby saving space at run time.
If you know that execution of the current load will not
reference certain entry points, you can use /NOENTRY to
delete them.
/NOENTRY differs from /NOREQUEST in
deletes requests for symbols, while
symbols that might be requested.

EXAMPLES

*/ENTRY ~
[LNKLSS LIBRARY SEARCH SYMBOLS
SQRT.
3456
* /NOENTRY: (SQRT.) ~
*/ENTRY ~

that
/NOREQUEST
/NOENTRY deletes

(ENTRY POINTS)]

I
I

Deletes SQRT.
so that it cannot
symbol request.

used

fulfill

OPTIONAL
NOTATIONS

You can omit the parentheses if only one symbol is given.

RELATED
SWITCHES

/ENTRY, /EXCLUDE,
/NOEXCLUDE,
/MISSING, /REQUEST, /NOREQUEST

3-38

/INCLUDE,

/NOINCLUDE,

USING LINK DIRECTLY
/NOINCLUDE

FORMAT

/NOINCLUDE

FUNCTION

Clears requests for
previous /INCLUDE.

EXAMPLE

*LIBI/INCLUDE: (MODI,MOD3) ~
* /NOINCLUDE ~

modules

that

were

specified

*
Loads MODI and MOD3 from LIBI.
However,
if
are not found immediately, stop searching.
RELATED
SWITCHES

/INCLUDE, /EXCLUDE, /MISSING

3-39

the

modules

USING LINK DIRECTLY
/NOINITIAL

FORMAT

/NOINITIAL

FUNCTION

Prevents loading of LINK's initial global symbol table
(JOBDAT) .
The /NOINITIAL switch cannot operate after the
first file specification because JOBDAT will be already
loaded.
The initial global symbol table contains the
JBxxx symbols described in Appendix C.
The /NOINITIAL switch is commonly used for:

EXAMPLES

•

Loading LINK
JOBDAT) .

itself

•

Loading a private
necessary) .

•

Building an .EXE file
executive mode
(for
loader) .

(to
copy

* /NOINITIAL GID
*

3-40

get
of

the

latest

JOBDAT

(to

copy
alter

of
if

that will eventually run in
example, a monitor or bootstrap

USING LINK DIRECTLY
/NOLOCAL

FORMAT

/NOLOCAL

FUNCTION

Suspends the effect of a preceding /LOCALS switch so that
local symbol tables will not be loaded with their modules.
The /LOCALS and /NOLOCAL switches may be used
locally or globally. If the switch is suffixed to
specification, it applies only to that file;
if it
suffixed to a file specification, it applies
following files in the same command string.
This switch is useful if you need
space, because local symbols are
segment by default.

EXAMPLES

either
a file
is not
to all

to conserve memory
loaded into the low

* /LOCALS A, B/NOLOCAL ,C ,/NOLOCAL D G!:.D
*
Loads A with local symbols, B without local symbols,
with local symbols, and D without local symbols.

OPTIONAL
NOTATIONS

Abbreviate /NOLOCAL to /N.

RELATED
SWITCHES

/LOCALS

3-41

USING LINK DIRECTLY
/NOREQUEST

FORMAT

/NOREQUEST: (symbol,symbol, ... )

FUNCTION

Deletes references to links from LINK's overhead tables
when loading overlay programs.
If you know that the
execution of the current load will
not
require certain
links,
you can use /NOREQUEST to delete references to
them.
/NOREQUEST differs from /NOENTRY in that /NOENTRY deletes
symbols that might be requested, while /NOREQUEST deletes
the requests for them.

EXAMPLES

*/REQUEST ~
[LNKRER REQUEST EXTERNAL REFERENCES]
ROUTN.
SQRT.
*/NOREQUEST: (ROUTN. ,SQRT.)~
*/REQUEST ~

*
Deletes references to ROUTN.

and SQRT.

OPTIONAL
NOTATIONS

You can omit the parentheses if only one symbol is given.

RELATED
SWITCH

/NOENTRY

3-42

USING LINK DIRECTLY
/NOSEARCH

FORMAT

/NOSEARCH

FUNCTION

Suspends the effect of a previous /SEARCH switch.
Files
named between a /SEARCH and the next /NOSEARCH are
searched as libraries, so that modules are loaded only to
resolve global references.
The /SEARCH and /NOSEARCH switches may be used
locally or globally.
If the switch is suffixed to
specification, it applies only to that file;
if it
suffixed to a
file
specification,
it applies
following files in the same command string.

EXAMPLES

*FILEI ~
* /SEARCH A ,B/NOSEARCH, C ,/NOSEARCH D ~

*
Searches A, loads B, searches C, and loads D.
RELATED
SWITCHES

/SEARCH

3-43

either
a file
is not
to all

USING LINK DIRECTLY
/NOSTART

FORMAT

/NOSTART

FUNCTION

Directs LINK to disregard any start addresses found
after
the /NOSTART switch.
Normally LINK keeps the most recent
start address found,
overwriting any previously found.
The /NOSTART switch prevents this replacement.

EXAMPLES

*MAINI , /NOSTART MAIN2, MAIN3 ~

*
Directs LINK to save the start address from MAINI
instead
of replacing it with other start addresses from MAIN2 and
MAIN3.
RELATED
SWITCHES

/START

3-44

USING LINK DIRECTLY
/NOSYMBOL

FORMAT

/NOSYMBOL

FUNCTION

Prevents construction of user symbol tables.
Symbols are
then not available for the map file, but the header for
the file can still be generated by the /MAP switch.
The /NOSYMBOL switch prevents writing an ALGOL SYM file if
it would otherwise have been written.
If you do not need the map file or symbols, you can
loading by using the /NOSYMBOL switch.

EXAMPLES

* /NOSYMBOL ~
*

3-45

speed

USING LINK DIRECTLY
/NOSYSLIB

FORMAT

/NOSYSLIB: (keyword, ... ,keyword)

FUNCTION

Prevents automatic search of the system libraries named as
keywords.
LINK usually searches system libraries at the
end of loading to satisfy unresolved global
references.
The /NOSYSLIB switch prevents this search.
The /NOSYSLIB switch can also be used to terminate
searching of libraries that were specified in a previous
/SYSLIB switch. When you specify searching of a library
with /SYSLIB,
that library will continue to be searched
for every module you load.
You can use /NOSYSLIB to
specify libraries that should not be searched.
Refer to
/SYSLIB for more information.
The permitted keywords and the libraries they specify are
listed below.
Only those printed in boldface specify
libraries supported by DIGITAL.
ANY
ALGOL
BCPL
COBOL
F40
FORTRAN
NELIAC
PASCAL
SAIL
SIMULA

EXAMPLES

Prevents
Prevents
Prevents
Prevents
Prevents
Prevents
Prevents
Prevents
Prevents
Prevents

all library searches.
search of ALGLIB.
search of BCPLIB.
search of LIBOL or C74LIB.
search of LIB40.
search of FORLIB.
search of LIBNEL.
search of PASLIB.
search of SAILIB.
search of SIMLIB.

*/NOSYSLIB: (ALGOL,COBOL) ~

*
Prevents search of the system libraries ALGLIB and LIBOL.

OPTIONAL
NOTATIONS

If you omit keyword it defaults to ANY.
You can omit parentheses if only one keyword is given.

RELATED
SWITCH

/SYSLIB

3-46

USING LINK DIRECTLY
/NOUSERLIB

]fORMAT

filespec/NOUSERLIB

FUNCTION

Discontinues automatic searching of the specified file at
each /LINK or /GO switch.
If you need a file searched for
some links but not others, you can use the /USERLIB and
/NOUSERLIB switches to enable and disable automatic search
of the file.

EXAMPLES

*/OVERLAY~
*MYFORL/USERLIB:FORTRAN~
*MODI/LINK:MODI~

*/NODE:MODI MOD2/LINK:MOD2~
*MYFORL/NOUSERLIB ~

*
Loads the overlay handler;
requests search of MYFORL as a
FORTRAN
library;
loads
MODI
and MOD2 as links;
discontinues search of MYFORL.
OPTIONAL
NOTATIONS

If you omit the filespec, LINK discontinues search of
all user libraries.

RELATED
SWITCHES

/USERLIB

3-47

USING LINK DIRECTLY
jONLY

FORMAT

jONLY:keyword

FUNCTION

Directs LINK to load only the specified segment
two-segment modules.
The permitted keywords are:
HIGH
LOW
BOTH

Loads only high segments.
Loads only low segments.
Loads both segments.

The jONLY switch is ignored for
for PSECTed modules.
EXAMPLES

one-segment

modules

and

*jONLY:HIGH MODI,MOD2~
*MOD3jONLY: BOTH ~

*
Loads high segment for MODI and MOD2;
for MOD3.

3-48

loads both segments

USING LINK DIRECTLY
/OTSEGMENT

FORMAT

/OTSEGMENT:keyword

FUNCTION

Specifies the time and manner of loading
system.

the

object-time

The permitted keywords are:
DEFAULT

Suspends the effect of
a
/OTSEGMENT:SHARABLE
/OTSEGMENT:NONSHARABLE switch.

HIGH

As for /OTSEGMENT:SHARABLE.

LOW

AS FOR /OTSEGMENT:NONSHARABLE.

previous
or

NONSHARABLE
Loads the object-time system into user
core image at load
time.
The user
program may have code in both segments.
The object-time system may have code in
both segments.
SHARABLE
Binds
the
object-time
system
at
execution time.
The user program is in
the low segment and the object-time
system is in the high segment.
LINK's default action is to bind the oqject-time system at
execution time.
This normal action occurs if none of the
following are true.
•

You specify /OTSEGMENT:NONSHARABLE.

•

You have loaded any code into the high segment.

•

You have specified /SEGMENT:HIGH for some modules.

•

You have specified /SYMSEG:HIGH.

•

Your low segment is too big for
systems to fit.

sharable

object-time

If any of these is true, a non-sharable object-time system
is loaded as part of your program.
EXAMPLES

*MYPROG/SYSLIB/OTSEGMENT:NONSHAR~

*
Loads a non-sharable copy of
part of your program.
RELATED
SWITCHES

/SEGMENT

3-49

the

object-time

system

USING LINK DIRECTLY
/OVERLAY

FORMAT

filespec/OVERLAY~ (keyword, ••• ,keyword)

FUNCTION

Initiates construction of an overlay structure.
discussion of overlay structures, see Chapter 5.

For

The permitted keywords and
their meanings are
listed
below.
The default settings are printed in boldface.

•

ABSOLUTE

Specifies that links are absolute.
This
is the default situation when
overlays are loaded.
The
inverse
situation
is
to
use
/OVERLAY:RELOCATABLE.
Relocatable
overlays are described in Chapter
5.

LOGFILE

Outputs runtime overlay messages to
your terminal.

NOLOGFILE

Suppresses
output
overlay messages •

NOWARNING

Suppresses
messages.

PATH

Specifies that each link path
be loaded with its link.

RELOCATABLE

Specifies
relocatable.

TREE

Specifies that
the overlay
have a tree structure.

WARNING

Outputs overlay warning messages to
user terminal.

WRITABLE

Specifies that
the
links
are
writable.
Refer
to Chapter 5 for
more information.

warning

overlay

that

runtime

links

will
are
will

EXAMPLES

See Chapter 5.

OPTIONAL
NOTATIONS

You can omit the parentheses if only one keyword is given.

3-50

January 1985

USING LINK DIRECTLY
/PATCHSIZE

FORMAT

/PATCHSIZE:n
Where n is a positive decimal integer.

FUNCTION

Allocates n words of storage to precede the symbol
table.
The allocated storage is in the same segment (high or low)
as the symbol table.
The default is /PATCHSIZE:64.
The storage allocated is available for patching or for
defining new symbols with DDT, and is identified by the
global symbol "PAT .. "

EXAMPLES

*/SYMSEG:HIGH/PATCHSIZE:200~

*
Loads the symbol
table
in the high
segment
after
allocating 200 words between the last loaded module and
the symbol table.
OPTIONAL
NOTATIONS

You can specify the patchsize in octal.

RELATED
SWITCHES

/SYMSEG

3-51

USING LINK DIRECTLY
/PLOT

FORMAT

filespec/PLOT

FUNCTION

Directs LINK to output a
tree diagram of your overlay
structure.
You can have
the diagram formatted for a
plotter (by default) or for a line printer (by giving the
device as LPT:).
Each box in the diagram shows a link number, its name
(if
you gave one with the /LINK switch), and its relationship
to other links (as defined by your commands).
The /PLOT switch cannot precede the /OVERLAY switch.

EXAMPLES

See Chapter 5.

OPTIONAL
NOTATIONS

LINK has default settings for
the size of the overlay
diagram and the increment for drawing
lines.
You can
override these by giving the /PLOT switch in the form:
filespec/PLOT: (LEAVES:value,INCHES:value,STEPS:value)
Where the values for each parameter define:
INCHES

Width of diagram in inches.
The defaults are
INCHES:29
for plotter and INCHES:12 for line
printer.

LEAVES

Number of links without successors
that can
appear
in
one
row.
The defaults are
LEAVES:16 for plotter and LEAVES:8
for
line
printer.

STEPS

Increments per inch for drawing
defaults
are
STEPS:lOO for
STEPS:20 for line printer.

lines.
plotter

The
and

For line printer diagrams,
you cannot give INCHES or
LEAVES different
from the defaults.
The STEPS parameter
should be between 10 and 25.
For plotter diagrams, you should give INCHES and LEAVES in
a
ratio of about
2 to 1.
For example, INCHES:40 and
LEAVES:20.
If LINK cannot design the diagram on one page,
it will
automatically design subtrees for diagrams on more pages.
RELATED
SWITCHES

/LINK, /NODE, /OVERLAY

3-52

USING LINK DIRECTLY
/PLTTYP

FORMAT

/PLTTYP:keyword

FUNCTION

Allows a user to specify the type
generated by the /PLOT switch.

KEYWORDS

DEFAULT

Generate output for a printer only if the
is a printer or terminal.

PLOTTER

Generate output for a plotter.

PRINTER

Generate output for a printer.

plot

file

device

EXAMPLES
.R LINK
*TEST/OVERLAY
*DSK:TEST/PLOT/PLTTYP:PRINTER
*OVL0,OVLI/LINK:TEST
*/NODE:TEST OVL2 /LINK:LEFT
*/NODE:LEFT OVL5 /LINK:LEFTI
*/NODE:LEFT OVL6 /LINK:LEFT2
*/NODE:TEST OVL3,OVL4 /LINK:RIGHT
*TEST /SAVE /GO
EXIT

Causes all output from the /PLOT
printer format.
RELATED
SWITCHES

switch

line

/PLOT

3-53

April 1986

USING LINK DIRECTLY
/PSCOMMON

FORMAT

/PSCOMMON:psect:common

FUNCTION

Specifies where LINK is to load COMMON blocks.
This
switch causes the FORTRAN common specified by the argument
common to be loaded into the PSECT specified in the
argument psect.
Use the /PSCOMMON switch before loading
the specified common and before declaring the common's
size with the /COMMON switch.
/PSCOMMON only affects common blocks defined with the
/COMMON switch.
If the common block is created by a REL
block, /PSCOMMON is ignored, and the PSECT specified by
the REL file is used.

EXAMPLES

In the following example, /SET defines the SECTA PSECT's
orIgIn, /PSCOMMON specifies that COMABC is loaded into
SECTA, and /COMMON defines the common size.
*/SET:SECTA:3000000 ~
*/PSCOMMON:SECTA:COMABC ~
*/COMMON:COMABC: 10000 ~
*PROG~

*
RELATED
SWITCHES

LINK V6.0

/COMMON

3-54

April 1986

USING LINK DIRECTLY
/REDIRECT

FORMAT

/REDIRECT:lowpsect:highpsect

FUNCTION

Loads two-segment formatted REL files as part of a program
using PSECTs.
The argument lowpsect is the name of the
PSECT to receive the low-segment code and highpsect is the
name of the PSECT to receive the high-segment code.
You must redirect both the high and the low segments.

EXAMPLES

The following example loads
a
two-segment
program
(TWOPRT), and displays the low- and high-segment values
using /COUNTERS.
*TWOPRT G!D
* /COUNTERS G!D
[LNKRLC Reloc. ctr.
.LOW.
.HIGH.

initial value
IlJ

41lJ1lJ1lJ1lJ1lJ

current value
1642
41lJ1lJ753

limit value
leJeJeJllJllJeJ
leJllJeJllJllJllJ]

*
Next, PSECT origins are set for PSHI and PSLO, .LOW.
is
redirected into PSLO, .HIGH. is redirected into PSHI, and
/COUNTERS is used to display PSHI and PSLO values.
*/SET:PSHI:4eJeJllJleJ ~
*/SET: PSLO: 35eJ0 ~
*/REDIRECT:PSLO:PSHI~
*TWOPRT~
*/COUNTERS ~

[LNKRLC Reloc. ctr.
PSHI
PSLO

initial value
4eJ0eJleJ
3500

current value
4eJeJ753
52eJ2

limit value
leJeJeJf.?JeJeJ
If.?Jf.?Jf.?JeJ0eJ]

LINK V6.1lJ

3-54.1

April 1986

USING LINK DIRECTLY
/REQUEST

FORMAT

/REQUEST

FUNCTION

Requests terminal typeout of all
other links.

external

references

If you use /REQUEST to get the names of
external
references, you can then either delete the references with
the /NOREQUEST switch, or load the referenced modules.
EXAMPLES

*/REQUEST<RET)
[LNKRER REQUEST EXTERNAL REFERENCES]
ROUTN.
SQRT.
*/NOREQUEST:ROUTN.<RET)
*/SEARCH LIBI<RET)

*
Obtains the external references ROUTN.
and SQRT.; deletes
the request for ROUTN.i
searches the file LIBI for a
module containing the entry point SQRT.
RELATED
SWITCHES

/NOREQUEST

3-54.2

April 1986

USING LINK DIRECTLY
/REQUIRE

FORMAT

/REQUIRE: (symbol, ... ,symbol)

FUNCTION

Generates global requests for the specified symbols.
LINK
uses these symbols as library search symbols
(entry
points) .
/REQUIRE differs from /INCLUDE in that /INCLUDE requests a
module by name, while /REQUIRE requests an entry name
symbol.
Thus you c~n use /REQUIRE to specify a
function
(for example,
SQRT.)
even if you do not know the module
name.
You can use /REQUIRE to load a module into a
to all links that reference the module.

link

common

Note that the global requests generated by the /REQUIRE
switch do not use the standard calling sequence, and are
therefore not visible to the /REQUEST switch.
EXAMPLES

* /UNDEFINED ~
[LNKUGS NO UNDEFINED GLOBAL SYMBOLS]
*/REQUIRE: (ROUTN. ,SQRT.) ~
* /UNDEFINED G!!)
[LNKUGS 2 UNDEFINED GLOBAL SYMBOLS]
ROUTN.
SQRT.

*
OPTIONAL
NOTATIONS

You can omit the parentheses if only one symbol is given.

RELATED
SWITCHES

/SEARCH, /NOSEARCH

3-55

USING LINK DIRECTLY
/REWIND

FORMAT

/REWIND

FUNCTION

Rewinds the current input or output device if
is a tape.
If not, the switch is ignored.

EXAMPLES

*MTAO:/REWIND~

*
Rewinds tape on MTAO:.

3-56

the

device

USING LINK DIRECTLY
/RUNAME

FORMAT

/RUNAME:name

FUNCTION

Assigns a job name for execution of your program.
This
name is stored inside the monitor and is used in the
SYSTAT display.
If you give no /RUNAME switch, the default name is the
name of the module with the start address. If there is no
such module, the name nnnLNK is used, where nnn is your
3-digit job number.

EXAMPLES

*/RUNAME:LNKDEV~

*
Assigns the name LNKDEV for job execution.

3-57

USING LINK DIRECTLY
/RUNCOR

FORMAT

/RUNCOR:nP
Where n is a positive decimal integer.

FUNCTION

Allocates n pages of memory for the program's low
at execution time.

EXAMPLES

*MYPROG/RUNCOR:22P/EXECUTE/GO~

segment

[LNKXCT MYPROG Execution]
Specifies that MYPROG will
allocation of 22 pages.
OPTIONAL
NOTATIONS

execute

with

low-segment

You can specify the argument in octal.
You can specify the switch argument as K instead of P.

3-58

USING LINK DIRECTLY
/SAVE

FORMAT

filespec/SAVE

FUNCTION

Directs LINK to create an .EXE file.
The file extension
defaults to .EXE.
For example, if you enter FOO.BAR/SAVE,
LINK creates a file FOO.EXE.
Note that if you want to run the saved file with
system command, the file extension must be .EXE.

EXAMPLES

the

*MYPROGG!!)

*DSKZ:GOODIE.EXE/SAVE/GO~

*
Directs LINK to save
GOODIE.EXE on DSKZ:.
RELATED
SWITCH

the

/SSAVE

3-59

linked

version

MYPROG

USING LINK DIRECTLY
/SEARCH

FORMAT

/SEARCH

FUNCTION

Directs LINK to load selectively from all following
files
up to the next /NOSEARCH or /GO.
These files are searched
as libraries, and only modules whose entry point name
resolves a global request are loaded.
Using /NOSEARCH discontinues the library search mode,
but
for each link
the system libraries are still searched
(unless you used the /NOSYSLIB switch), and user libraries
are still searched (if you used the /USERLIB switch).
The /SEARCH and /NOSEARCH
locally or globally.

switches

may

used

either

Note that search requests in .TEXT blocks may be processed
in the
reverse order of the entered /SEARCH switches.
Keep this in mind when specifying the order in which the
modules are to be searched.
See Block Types Greater Than
3777 in Appendix A for more information.
EXAMPLES

*/SEARCH A,B/NOSEARCH,C,/NOSEARCH D~

*
Searches A, loads B, searches C, and loads D.
RELATED
SWITCHES

/NOSEARCH

3-60

January 1985

USING LINK DIRECTLY
/SEGMENT

FORMAT

/SEGMENT:keyword

FUNCTION

Specifies which segment is to be used for
loading
following modules.
FORTRAN object code is an exception;
both segments are loaded into the low segment unless one
or more of the following is true:

• You used the /OTSEGMENT:NONSHARABLE switch.
used the /SEGMENT:HIGH switch to load code
• You
the high segment.

into

used the /SEGMENT:DEFAULT switch to load code into
• You
both segments.

• Some code is already loaded into the high segment.
The keywords for the /SEGMENT switch are:
DEFAULT Suspends
effect
/SEGMENT:HIGH.

/SEGMENT:LOW

HIGH

Load into high segment, even if impure code.

LOW

Loads into low segment.

NONE

Same as DEFAULT.

If the switch is suffixed to a file specification,
it
applies only to that file;
if it is not suffixed to a
file specification, it applies to all following files in
the same command string.
EXAMPLES

*/SEGMENT:LOW MODI,MOD2,/SEGMENT:HIGH

MOD3~

*
Loads MODI and MOD2 into the low segment;
loads MOD3 into
the high segment even if its code is impure.
RELATED
SWITCHES

/OTSEGMENT

3-61

USING LINK DIRECTLY
/SET

FORMAT

/SET:name:address
Where name is .HIGH., .LOW., or a PSECT name, and
is a 30-bit octal address or a defined symbol.

I
FUNCTION

Sets the loading position of a PSECT, or sets
or .LOW.
relocation counter.

address

the

.HIGH.

For setting the loading position of a PSECT, name is the
name of the PSECT, and address is a virtual memory
address. The /SET switch must precede the modules that
will make up the specified PSECT. The /SET switch is not
needed if the
REL
files
already
contain
origin
information.
NOTE
If you load PSECTs so that the resulting core
image contains gaps, you must generate an EXE file
and execute that file (rather than executing the
loaded core image).
It is good practice to
generate an .EXE file for all PSECTed programs.
If you do not ask for an .EXE file and you need one,
will generate one for you.
EXAMPLES

LINK

*/SET:A: 200000 G!D

*
Specifies that the PSECT named A is to be loaded with
origin at address 200000.

its

* /SET: • HIGH. : 400000 G!D

*
Sets the high segment relocation counter .HIGH.
to the
address 400000~
Note that saying /SET:.HIGH. causes a
high segment to appear and a vestigial JOBDAT area to be
built.
RELATED
SWITCHES

LINK V6.0

/COUNTER, /LIMIT

3-62

April 1986

USING LINK DIRECTLY
/SEVERITY

FORMAT

/SEVERITY:n

FUNCTION

Specifies that messages of severity level greater
than n
will
terminate the load,
where n is a decimal number
between 0 and 30 inclusive.
Level 31 messages always
terminate the load.
The defaults are /SEVERITY:24 for
/SEVERITY:16 for batch jobs.

EXAMPLES

timesharing

*/SEVERITY:30~

*
Specifies that only level 31 messages are fatal.

3-63

jobs,

and

USING LINK DIRECTLY
/SKIP

FORMAT

/SKIP:n
Where n is a positive decimal integer.

FUNCTION

Skips forward over n files on the current tape device.
(A
tape device remains current only until end-of-line or
until another device is specified, whichever
occurs
first.)
If the device
is not a
tape,
the switch is
ignored.

EXAMPLES

*MTAO:/SKIP:4 ~

*
Skips forward over 4 files on MTAO:.
RELATED
SWITCHES

/BACKSPACE, /MTAPE, /REWIND, /UNLOAD

3-64

USING LINK DIRECTLY

/SPACE

FORMAT

/SPACE:n
Where n is a positive decimal integer.

FUNCTION

Specifies that n words of memory will follow the current
link at execution time.
This memory allocation will not
increase the size of the overlay file,
but it will
increase the size of the program at run time.
The /SPACE switch is used to allocate space for use by the
object time system.
The OTS uses this space for I/O
buffers, and as scratch space in FORTRAN and heap space in
ALGOL.
You should place the /SPACE switch before the first
/LINK
switch,
to ensure allocation for the root link.
It is
possible to allocate space after one or more overlays are
linked.
This might be useful if an overlay has unusual
storage requirements:
buffers for a file which
is open
only while that overlay is resident, or a large local
matrix.
To allocate space between overlays,
use /SPACE
when loading
the overlay that will be using this file or
matrix.
LINK allows one /SPACE switch for the root node,
and one for each overlay.
The default amount of memory allocated,
if you do not
specify /SPACE, is 2000 for the root link and 0 (zero) for
other links.
If the space allocated
for
a
relocatable link
is too
small,
the overlay handler can relocate it.
If the space
allocated for an absolute link is too small, a fatal error
occurs.

EXAMPLES

* lOVE RLA Y G£)
*TEST/SPACE:90/LINK:MAIN G£)
*
/NODE:MAIN SUBI/LINK:SUBI~
*
/NODE:MAIN SUB2/LINK:SUB2G£)

*
Allocates 90 words of memory to follow the root link
for
the program.
See Chapter 5 for a discussion on overlay.
OPTIONAL
NOTATIONS

You can specify the number of words in octal.

3-65

USING LINK DIRECTLY
/SSAVE

FORMAT

filespec/SSAVE

FUNCTION

Specifies the same actions as the /SAVE switch, except
that at execution time the program's high segment will be
sharable. The extension of the file created by LINK is
always EXE;
other file extensions are ignored. If, for
example you enter FOO.BAR/SSAVE, LINK creates a file
FOO.EXE.

EXAMPLES

*DSK: SHRPRG/SSAVE ~

*
Requests a sharable save file DSK:SHRPRG.EXE.

RELATED
SWITCH

/SAVE

3-66

USING LINK DIRECTLY
/START

FORMAT

/START:symbol
/START:address
/START
Where symbol is a defined global symbol and address
30-bit octal address.

FUNCTION

Specifies the start address for the loaded program, and
prevents replacement by any start addresses found later.
You can use the /START switch with no argument to disable
a previously given /NOSTART switch.

EXAMPLES

*MAIN l/START: ENTRY 1 ,MAIN2,MAIN3 G£)

*
Defines the start address as ENTRY 1 in MAIN1, and prevents
replacement of this start address by any others found in
MAIN 2 or MAIN 3.
RELATED
SWITCHES

LINK V6.0

/NOSTART

3-67

April 1986

USING LINK DIRECTLY
/SUPPRESS

FORMAT

/SUPPRESS:symbol
Where symbol is a previously defined global symbol.

FUNCTION

Used to suppress a previously defined global symbol.
If
the symbol
is unknown,
this switch has no effect. Use
this switch if a global symbol is defined in two modules
and you wish to suppress one of the definitions.
LINK suppresses a defined global symbol by setting
its
definition to undefined in the global symbol table.
LINK
does not remove the symbol definition from the symbol
table.
As a result, the symbol table built for debugging
contains both the old and new values of the symbol.
Since LINK sets the symbol
to undefined
in the symbol
table,
it expects that a subsequent module will be loaded
that contains a global definition for the symbol.
If the
symbol
is not defined later, LINK issues the Undefined
Global Symbol (LNKUGS) error.

EXAMPLES

In the following example, the ENTPTR symbol
is used
in
both the TEST and TEST2 programs.
First, LINK is run,
TEST is loaded, and the value of ENTPTR is shown using the
/VALUE switch •
• R LINKG!D
*TESTG!D
*/VALUE:ENTPTR~

[LNKVAL Symbol ENTPTR

140

defined]

Next, ENTPTR's value is suppressed using /SUPPRESS and its
current value is shown.
Note that the value is now
undefined.
*/SUPPRESS:ENTPTR~
*/VALUE:ENTPTR~

[LNKVAL Symbol ENTPTR

undefined]

Finally TEST2 is loaded and the value is shown again.
*TEST2~

*/VALUE:ENTPTR~

[LNKVAL Symbol ENTPTR

200

defined]

In the next example, TEST and TEST2 are loaded, but ENTPTR
is not suppressed after TEST is loaded.
In this example,
LINK issues the Multiply-defined global symbol warning •
• R LINK(§)
*TEST~

*TEST2
%LNKMDS Multiply-defined global symbol ENTPTR
Detected in module .MAIN from file TEST2.REL
Defined value = 140, this value = 200

3-68

January 1985

USING LINK DIRECTLY
/SYFILE

FORMAT

filespec/SYFILE:keyword

FUNCTION

Requests LINK to output a symbol file to the given
filespec,
and sets the /SYMSEG:DEFAULT switch.
If you
previously specified /NOSYM, the /SYFILE switch has no
effect.
The symbol file contains global symbols sorted for DDT.
If you used the /LOCALS switch, it also contains local
symbols, module names, and module lengths.
The permitted keywords and their meanings are:

EXAMPLES

ALGOL

Requests symbols in ALGOL's format.
The
first word of the table is "XWD 1044,
count." The remaining words are copied out
of Type 1044 REL blocks.
If an ALGOL main
program has been loaded, then /SYFILE:ALGOL
becomes the default.

RADIX50

Requests symbols in Radix-50 format.
The
first word of the table is negative. Each
symbol requires two words in the table:
the first
is the symbol name in Radix-50
format; the second is the symbol value.

TRIPLET

Requests symbols in triplet format.
The
first word of the table is zero. Each
symbol requires three words in the table:
the first word contains flags; the second
is the symbol name in SIXBIT; the third is
the symbol value.

*SYMBOL/SYFILE ~

*
Creates a symbol file called SYMBOL with
Radix-50 format.
OPTIONAL
NOTATIONS

the

symbols

If you omit the keyword, RADIX50 is assumed.

3-69

April 1986

USING LINK DIRECTLY
/SYMSEG

FORMAT

/SYMSEG:keyword

FUNCTION

Places the symbol table so that it will not be overwritten
during execution or debugging.
Keywords and their meanings are:

,
EXAMPLES

DEFAULT

Places the symbol table in the low segment,
except
for
overlaid
programs.
For
overlays, symbols are not loaded.

HIGH

Places the
segment.

LOW

Places the symbol table in the low segment.

NONE

Prevents loading of the symbol table.

PSECT:name

Places the symbol table at the end of the
PSECT (after allocating any space required
by the /PATCHSIZE switch).

symbol

table

the

high

*/SYMSEG: LOW C§)

*
Places the symbol table in the program low segment.
RELATED
SWITCHES

/LOCALS, /NOLOCALS

3-70

April 1986

USING LINK DIRECTLY
/SYSLIB

FORMAT

/SYSLIB:keyword

FUNCTION

Forces searching of one or more
system
libraries,
immediately after you end the command line.
LINK will
also automatically search a system library if code from
the corresponding compiler has been loaded.
By default,
LINK searches the system libraries that are appropriate
for
the language compiler, after all the modules of the
program are loaded.
/SYSLIB forces
the search to take
place immediately.
After you specify a library with /SYSLIB, the library you
specified will be searched every time you load a module,
until you use /NOSYSLIB to end searching of that library.
The permitted keywords and the libraries they specify are
listed below. Those printed in boldface specify libraries
supported by DIGITAL.
ANY
ALGOL
BCP
COBOL
F40
FORTRAN
NELIAC
PASCAL
SAIL
SIMULA

EXAMPLES

Forces search of all system libraries.
Forces search of ALGLIB.
Forces search of BCPLIB.
Forces search of LIBOL or C74LIB.
Forces search of LIB40.
Forces search of FORLIB.
Forces search of LIBNEL.
Forces search of PASLIB.
Forces search of SAILIB.
Prevents search of SIMLIB.

*TESTI/SYSLIB:ALGOL~

*TEST2/NOSYSLIB:ALGOL

*
Where TESTI is a FORTRAN module,
LINK will search both
FORLIB and ALGLIB for TESTI. Where TEST2 is a FORTRAN
module, LINK will search only FORLIB when TEST2 is loaded.
OPTIONAL
NOTATIONS

You can omit the keyword.
LINK will search all libraries
for which corresponding code has been loaded.

RELATED
SWITCHES

/NOSYSLIB

3-71

USING LINK DIRECTLY
/TEST

FORMAT

/TEST:keyword

FUNCTION

Loads the debugging program indicated by keyword.
Unlike
the /DEBUG switch, /TEST causes execution to begin in the
loaded program (not in the debugging module).
This switch
is useful
if you expect the program to run successfully,
but want the debugger available in case the program has
errors.
The /TEST switch turns on the /LOCALS switch for
the
remainder of the load. You can override this by using the
/NOLOCAL switch,
but the override lasts only during
processing of the current command string.
Local symbols for the debugging module
loaded.

itself

are

The permitted keywords and the programs they load
listed
below.
Only those printed in boldface
supported by DIGITAL.

ALGDDT
ALGOL
COBDDT
COBOL
DDT
FAIL
FORDDT
FORTRAN
MACRO
PASCAL
PASDDT
SAIL
SDDT
SIMDDT
SIMULA

EXAMPLES

never
are
are

Loads ALGDDT.
Loads ALGDDT.
Loads COBDDT.
Loads COBDDT.
Loads DDT.
Loads SDDT.
Loads FORDDT.
Loads FORDDT.
Loads DDT.
Loads PASDDT.
Loads PASDDT
Loads the SAIL debugger.
Loads the SAIL debugger.
Loads SIMDDT.
Loads SIMDDT.

*MYPROG/TEST: FORTRAN ~

*
Loads MYPROG and FORDDT.
OPTIONAL
NOTATIONS

If you give no keyword with /TEST,
the default is either
DDT or the debugging program specified by the /DDEBUG
switch.

RELATED
SWITCHES

/DDEBUG, /DEBUG

3-72

USING LINK DIRECTLY
/UNDEFINED

FORMAT

/UNDEFINED

FUNCTION

Requests terminal typeout (in octal) of undefined global
symbols.
You can use /UNDEFINED to get a list of
undefined symbols, and then define them with the /DEFINE
switch.

EXAMPLES

* /UNDEFINED ~
[LNKUGS 2 UNDEFINED GLOBAL SYMBOLS]
A
400123
IGOR
402017
*/DEFINE: (A:59l,IGOR:l) ~

*
Gives the decimal
respectively.

values

591

and

OPTIONAL
NOTATIONS

You can abbreviate /UNDEFINE to /U.

RELATED
SWITCHES

/DEFINE, /VALUE

and

IGOR,

3-73

USING LINK DIRECTLY
/UNLOAD

FORMAT

device/UNLOAD

FUNCTION

Rewinds and unloads the specified tape device.
(This
switch is ignored
if the current device is not a tape
device.)
The /UNLOAD is not performed until
the current
file processing is completed.

EXAMPLES

*MTAO: /UNLOAD ~

*
Rewinds and unloads MTAO.
RELATED
SWITCHES

/BACKSPACE, /MTAPE, /REWIND, /SKIP

3-74

USING LINK DIRECTLY
/UPTO

FORMAT

/UPTO:addr
Where addr is a 30-bit octal address
upper limit to which the symbol
address can be replaced by a symbol.

that specifies
table can grow.

the
The

FUNCTION

Sets an upper limit to which the symbol table can expand.

EXAMPLE

*/UPTO: 550000 ~

*
Included in a FORTRAN load, this switch would override the
default upper bound for the symbol table. This might be
used if FOROTS begins above 550000.
RELATED
SWITCH

LINK V6.0

/SYMSEG

3-75

April 1986

USING LINK DIRECTLY
/USERLIB

FORMAT

filespec/USERLIB: (keyword, ... ,keyword)

FUNCTION

Directs LINK to search the user library given by filespec
before searching system libraries. The keyword indicates
that the given library is to be searched only if code from
the corresponding compiler was loaded.
Keywords and their meanings are given below.
Only those
printed in boldface indicate compilers and libraries
supported by DIGITAL.
ALGOL
ANY
BCPL
COBOL
FORTRAN
NELIAC
PASCAL
SAIL
SIMULA

EXAMPLES

Search
Always
Search
Search
Search
Search
Search
Search
Search

as an ALGOL library.
search this library.
as a BCPL library.
as a COBOL library.
as a FORTRAN library.
as a NELIAC library.
as a PASCAL library.
as a SAIL library.
as a SIMULA library.

*MYFORL/USERLIB:FORTRAN ~

*
Directs LINK to search the user library MYFORL
(before
searching FORLIB) if any FORTRAN-compiled code is loaded.

OPTIONAL
NOTATIONS

You can omit the parentheses if only one keyword is given.

RELATED
SWITCHES

/NOUSERLIB, /SYSLIB

3-76

CHAPTER 4
OUTPUT FROM LINK

The primary output from LINK is the executable program formed from
your input modules and switches. During its processing, LINK gives
errors, warnings, and informational messages. At your option, LINK
can generate any of several files.

4.1

THE EXECUTABLE PROGRAM

The executable program that LINK generates
(called the core image)
consists mostly of data and machine instructions from your object
modules.
In the core image, all relocatable addresses have been
resolved
to absolute addresses, and the values of all global
references have been resolved.
You have several options for loading the
purpose of the load. Those options are:
•

program,

depending

the

Execute the program. To do this, include the /EXECUTE switch
any place before the /GO switch.
LINK will pass control to
your program for execution.

the program under the control of DDT.
To do this,
• Execute
use
the
/DEBUG
switch
before the first input file
specification.

4.2

•

Execute the program and debug it after execution.
To do
this,
use the /TEST and /EXECUTE switches before the first
input file specification. After execution, type DDT to the
system to enter the debugging program.

•

Save the core image as an EXE file.
/SAVE switch.
See Section 4.2.

this,

use

OUTPUT FILES

At your option, LINK can produce any of the following output files:
•

Saved (executable) file.

•

Log file.

•

map file.

4-1

the

OUTPUT FROM LINK

4.2.1

•

Symbol file.

•

Plotter file (see Section 5.1).

•

Overlay file (see Section 5.1).

Executable Files

The executable file, sometimes called the saved or
.EXE file,
is a
copy of the completed core image generated by LINK.
You can create an
executable file by supplying the /SSAVE switch before the /GO switch
when you are loading the program with direct commands to LINK. The
executable file will retain the same file name as the source program,
with a file extension .EXE.
Alternatively, you can type the file specification, followed by /SSAVE
(or /SAVE),
and the executable file will be written to the file you
specified.
If you load the program with the system LOAD command, you
may then save the executable file by typing the system SAVE command.
You can run the executable file later, without running LINK, by using
the system command RUN, or the two system commands GET and START. The
following section describes the
internal format of the executable
file.
See Chapter 3 for descriptions of /SAVE and /SSAVE switches.

4.2.1.1 Format of Sharable Save Files - A sharable save file
is
divided
into two main areas:
the directory area, which contains
information about the structure of the file, and the data area, which
contains the data of the file.
The following diagram illustrates the general
save file:
Directory
Area:

format

sharable

==========~========~====

Directory Section

1----------------------1
1 Entry Vector Section 1
1----------------------1
1 Terminating Section
========================

Data Area:

Data Section

The directory area of the sharable save file has three distinct
sections:
the directory section, the entry vector section, and the
terminating section. The size of the directory area depends on the
access characteristics of the pages in the data area of the save file.

LINK V6.0

4-2

April 1986

OUTPUT FROM LINK
Each of the sections in the directory area begins with a header word
containing its identifier code in the left half and its length in the
right half.
Each section is described in the following paragraphs.
The directory section is the first of the three sections and describes
groups of contiguous pages that have identical access.
The length of
this section varies according to the number of groups that can be
generated from the data portion of the save file.
The more data pages
that can be combined into a single group, the fewer groups required,
and the smaller the directory section.
The format of the directory section is as follows:
17 18

8 9

1======================================:================1

Identifier code
1776

Number of words
(including this word)
in directory section

1=======================================================
Access
bits

Page number in file, or 0 if group
of pages is all zero

1=======================================================
Repeat
count

Page number in the process

1=======================================================
1=======================================================1

1 Access bits

Page number in the file

J========================~==============================1

1 Repeat count 1

Page number in the process

!=========:==:=================~========================!

PSECT attributes are used to set the access
description of Block Type 24 in Appendix A.

bits.

Refer

the

The directory section has one header word containing 1776 count, where
count is the number of words in the directory section, including this
header word.
words

Word 0, .SVFPF, specifies the access flags and the page number in
file.
The flag bits are:

the

The header word is followed by word pairs.
formatted as follows:

Bit

Symbol

Meaning

0
1

SV%HIS
SV%SHR
SV%WRT
SV%CON
SV%SYM

Page
Page
Page
Page
Page

3
4

is
is
is
is
is

Each

pair

in high segment.
sharable.
writable.
concealed.
part of symbol table.

Word I, .SVPPC, contains the repeat count in Bits 0-8,
number in the process in the remaining bits.

LINK V6.0

4-3

and

the

page

.Apri1 1986

OUTPUT FROM LINK
The repeat count is the number (minus 1) of consecutive pages in the
group described by the word pair. Pages are considered to be in a
group when the following three conditions are met:
1.

The pages are contiguous.

The pages have the same access.

The pages are allocated but not loaded.

A group of all zero pages is indicated by a file page number of 0.
The word pairs are repeated for each group of
space.

pages

the

address

The entry vector section follows the directory section. It points to
the first word of the entry vector, and gives the length of the
vector.
17 18

1=============:================================~========1

Identifier code
1775

Number of words
(including this word)
in entry vector section

1=~=====================================================1

254000

1===============================~=======================1

Starting address
1==~================================~===================1

This format is the default. However, if you make special provisions
in your program, the format becomes the following.
(Refer to the
description of Block Type 7 in Appendix A for further information.)
17 18

1=======================================================1

1
1

Identifier code
1775

Number of words
(including this word)
in entry vector section

1
1

1=======================================================1
Number of words in entry vector
1=======================================================1
1

Address of entry vector

1==~====================================================1

The data for this section is the address of the entry vector.
The terminating section, called the end section, always immediately
precedes the data section. The format of the terminating section is
the following:

1=======================================================1
1

Identifier code
1777

1=======================================================1
The data area follows the terminating section, beginning at
page boundary.

the

LINK V6.0

April 1986

4-4

OUTPUT FROM LINK
4.2.2

LOG Files

A LOG file is generated if you use the /LOG switch. LINK then writes
most of its messages into the specified file.
You can control the
kinds of messages entered in the LOG file by using the /LOGLEVEL
switch.
For an example of a LOG file, see Section 5.1.

4.2.3

Map files

The map file is generated if you use the /MAP switch. LINK constructs
a symbol map in this file.
The kinds of symbols included depends on
your use of the /CONTENTS, /LOCALS, /NOLOCALS, /NOINITIAL, and
/NOSYMBOLS switches.
For an example of a map file, see Section 5.1.
For a list of /MAP options, refer to Section 3.2.2.

4.2.4

Symbol Files

The symbol file (or SYM file) is generated if you use the /SYFILE
switch.
This file contains all global symbols, module names, and
module lengths, and,
if you used the /LOCALS switch, all local
symbols.

4.3

SYMBOL TABLE VECTOR

A symbol table vector is a pointer to the symbol tables of a program.
There is one symbol table vector, and an undefined and defined symbol
table per program.
When an extended symbol table is used, the contents of .JBUSY in
JOBDAT are zeroed, and the address of the symbol table vector is
loaded into .JBSYM. The symbol table vector contains two pointers:
one to defined RADIX-50 symbols, the other to undefined RADIX-50
symbols.
The symbol table vector contains subtables that point to each symbol
table and give their length and type.
Each subtable is three words
long, although only the first two words are currently used.
The
format of a symbol table vector is illustrated below.

LINK V6.0

4-5

April 1986

OUTPUT FROM LINK

516

==:~===============================

Symbol
Table
Vector

Sub- 1
Tablel
n

1
1

Vector

Length

Words

Type

Symbol table length

----------------------------------Symbol table pointer
I
Reserved for DIGITAL, must be 0

Sub- -Tablel
n

Type I

table length I

Symbol

1
1
1
1

Symbol

table

pointer

I Reserved for DIGITAL, must be 0 I
========:===:======~:==============

Symbol Table
Word

Symbol

Meaning

.SYSTL

Defines the length in words
vector including this word.

.SYTYP

First subtable word,
fields:
SY.TYP

the

symbol

table

containing

the

following

two

is a 6-bit field that contains
table type.

the

symbol

The types are:
Code

Name

Type

.SYRD5
.SYR5U

Radix-50
Radix-50
Reserved
Reserved

3-37
40-77
SY.LEN
1

• SYADR

defined symbols
undefined symbols
for DIGITAL
for customers

is a 30-bit field that contains the length in
words of the particular symbol table.

Lowest word in the table •
If bit 0 is 1, this word contains a section-local
address.
If bit 0 is 0, this word contains a global
address.
A section-local address is an
18-bit
address.
A global address is a 30-bit address.

The Reserved word must be zero.

LINK V6.0

4-6

April 1986

OUTPUT FROM LINK
4.4

MESSAGES

During its processing, LINK issues messages about what
it is doing,
and about errors or possible errors it finds.
LINK also responds to
query switches such as /COUNTER, /ENTRY, /MISSING,
/REQUEST, and
/UNDEFINED.
Each LINK message has an assigned level and an assigned severity.
(See Appendix B for the level and severity of each message.)
The level of a message determines whether it will be output to your
terminal, the log file, or both.
You can control this output by uSlng
the /ERRORLEVEL switch for the terminal and the /LOGLEVEL switch for
the log file.
LINK's defaults are /ERRORLEVEL:10 and /LOGLEVEL:10.
Responses to query switches and messages that require you to do
something
immediately are never output to the LOG file.
For example,
if you use the /UNDEFINE switch, LINK responds with the LNKUGS
message;
this message is output to the terminal but not to the log
file.
The severity of a message determines whether LINK considers the
message fatal
(that is, whether the job is terminated). You can set
the fatal severity with the /SEVERITY switch. The default severities
are 24 for interactive jobs and 16 for batch jobs.
For both terminal messages and log file entries, LINK can issue short,
medium, or long messages, depending on your use of the /VERBOSITY
switch. For /VERBOSITY:SHORT, LINK gives only a 6-letter code;
for
/VERBOSITY:MEDIUM,
LINK gives the code and a medium-length message;
for /VERBOSITY:LONG, LINK gives the code, a medium-length message, and
a long message.
Appendix B gives each 6-letter message code,
long messages, and its level and severity.

4-7

its

medium-length

and

April 1986

CHAPTER 5
OVERLAYS

If your loaded program is too large to execute in one piece, you may
be able to define an overlay structure for it.
This permits the
system to execute the program with only some parts at a time in your
virtual address space.
The overlay handler removes and reads in parts
of the program, according to the overlay structure.
NOTE
You only need an overlay structure if
your program is too large for your
virtual address space.
If the program
can fit
in your virtual space, you
should not define an overlay structure
for
it;
the monitor's page swapping
facility
is
faster
than
overlay
execution.

5.1

OVERLAY STRUCTURES

An overlay program has a tree structure.
(The tree
is usually
pictured upside down.)
The tree is made up of links, each containing
one or more program modules.
These links are connected by paths.
Using LINK switches, you define each link and each path.
At the top of the (upside down) tree is the root link, which must
contain the main program.
First-level links are below the root link;
each first-level link is connected to the root link by one path.
Second-level links are below the first-level
links,
and each is
connected by a path to exactly one first-level link.
A link at level
n is connected by a path to exactly one link at level n-l.
Notice that a link can have more than one downward path (to
links), but only one upward path (to predecessor links).

successor

Figure 5-1 shows a diagram of an overlay structure with 5 links.
root link
is TEST;
the first-level links are LEFT and RIGHT;
second-level links are LEFTl and LEFT2.

5-1

The
the

OVERLAYS

Figure 5-1

Example of an Overlay Structure

Defining an overlay structure allows your program to execute
in a
smaller space.
This is because the code in a given link is allowed to
make reference to memory only in links along a direct upward or
downward path.
In the structure in Figure 5-1, the link LEFT can reference memory in
itself,
in the root link (TEST), or in its successor links LEFTI and
LEFT2.
More generally, a link can reference memory in any link
that
is vertically connected to it.
Referencing memory in any other link is not allowed.
For example,
path from LEFTI to LEFT2 is not a direct upward or downward path.

Because of this restriction on memory references,
only one complete
vertical path
(at most) is required in the virtual address space at
anyone time.
The remaining links can be stored on disk while they
are not needed.

5.1.1

Defining Overlay Structures

LINK has a family of overlay-related switches.
These switches are
described
in detail
in Section 3.2.2.
The following example shows
command strings for defining the overlay diagrammed
in Figure 5-1.
(Some of the command lines in this example are indented for clarity.)

*TEST/LOG/LOGLEVEL:2
*/ERRORLEVEL:5
*TEST/OVERLAY
*TEST/MAP
*LPT:TEST/PLOT
*OVLO,OVLl/LINK:TEST
*
/NODE:TEST QVL2/LINK:LEFT
*
/NODE:LEFT OVL5/LINK:LEFTI
*
/NODE:LEFT OVL6/LINK:LEFT2
*
/NODE:TEST OVL3,OVL4/LINK:RIGHT
*TEXT/SSAVE
*/EXECUTE/GO

5-2

:Define TEST. LOG
:Important messages
iDefine TEST.OVL
:Define TEST.MAP
:Request diagram
iRoot link
:Left branch
:Left-left branch
:Left-right branch
:Right branch
:Define TEST.EXE

OVERLAYS
The first command string above defines the log file for the overlay.
TEST/LOG specifies that the file is named TEST.LOG.
The /LOGLEVEL:2
switch directs that messages of level 2 and above be entered
in the
log file.
In the second command string, the /ERRORLEVEL:5 switch directs that
messages of level 5 and above be typed out on the terminal.
The third
command string, TEST/OVERLAY, tells LINK that an overlay structure is
to be defined, and that the file fo~ the overlay is to be TESTOVL.
The fourth command string, TEST/MAP, defines the file TEST.MAP,
will contain symbol maps for each link.

which

The next command string, LPT:TEST/PLOT, directs that a tree diagram of
the overlay links be printed on the line printer.
The next command string, OVLO,OVLl/LINK:TEST, loads the files OVLO.REL
and OVLl.REL into the root link.
The /LINK:TEST switch tells LINK
that no more modules are to be in the root link, and that the link
name is TEST.
Each of the next four lines defines one link
form:

with

string

the

/NODE:linkname filename/LINK:linkname
The /NODE:linkname switch specifies the previously defined
link to
which
the
present
link
is
an
immediate
successor.
The
filenames/LINK:linkname part of the line names the files containing
modules to be included in the current link and specifies the name of
the link.
The first of these four lines begins with /NODE:TEST, which tells LINK
that the link being defined is to be an immediate successor to TEST,
the root link.
Then (on the same line),
the string OVL2/LINK:LEFT
loads the file OVL2.REL, ends the link, and names it LEFT.
The next line, /NODE:LEFT OVL5/LINK:LEFTl, defines a link named LEFTI
containing the file OVL5.REL, and this link is an immediate successor
to the link LEFT.
The next line, /NODE:LEFT OVL6/LINK:LEFT2, defines another
immediate
successor to LEFT, this time containing the file OVL6.REL and called
LEFT2.
The last
link
is
defined
in
the
next
line,
/NODE:TEST
This string defines the link RIGHT, which is an
OVL3,OVL4/LINK:RIGHT.
immediate successor to TEST and contains the files OVL3.REL and
OVL4.REL.
The next-to-last line, TEST/SSAVE, directs LINK to create the saved
file TEST.EXE.
The last line, /EXECUTE/GO, specifies that the loaded
program is to be executed,
and that all commands to LINK are
completed.
The process also produced an executable file TEST.EXE, which can be
run using the RUN system command.
However, to run the program, the
file TEST.OVL must be present, because it provides the code for
the
links.

5-3

OVERLAYS
An Overlay Example

5.1.2

The following pages show terminal listings
with the example above.
These pages are:

the

files

associated

Terminal copy
overlay.

Terminal copy of the compilation of the source files.

Terminal copy of the interactive use of LINK
execute the overlay.

The file TEST. LOG generated by LINK,
messages issued during the load.

shows

the

log

The file TEST. MAP generated by LINK, which shows symbol
for the overlay.

maps

The tree diagram requested by the LPT:/PLOT switch.

the

FORTRAN

5-4

source

used

files

which

the

define

and

OVERLAYS
• tl'pe oldO. fa r
TYPE 1
FoRMAT('l','Execution begins in (,lain program ol.llO')
TYPE 11
11
FoRMAT(P(,'ol,110 calls ol.ll2A')
CAll ol,ll2A
TYPE 2
FoRMAT(fU{,'Return to ol,llO')
TYPE 21
21
FoRMAT(lX,'o~110 calls ol.llll')
CAll ol,llll
TYPE 2
TYPE 3
FoRMAT(/l){,'Execution ends in (,lain progra(,l ol,llO'//)
STOP
END
.tl'pe ol.rll.for
SUB ROUT I NE ol,lLl
TYPE 1
FoRMAT(/lX,'
CAll ol,ll3
TYPE 2
FoRMAT(/lX,'
2
RETURN
END
.t}'pe

Return to ol;ll')

o~)12ffor

SUBROUTINE oVl2A
TYPE 1
oVl2A c all s ol,llS')
FoRMAT(/lX,'
CAll ol,llS
TYPE 2
FORMAT ( / P( , '
Return to ol,ll2A')
TYPE 3
ol.ll2A calls mllG')
FORMAT ( P(, '
CAll ol.llG
TYPE 2
RETURN
END
SUBROUTINE oVl2B
TYPE 1
ol,ll2B doesn't call anl'thing')
FORMAT ( /1 X, '
RETURN
END

. t}' pe

ol,lll call s ol.ll3')

t}' pe

ov13.for
SUBROUTINE m l l3
TYPE 1
FoRMAT(flX, '
RETURN
END
ovlll.for
SUBROUTINE ol,llll
TYPE 1
FoRMAT(/lX,'
CAll oVll
TYPE 2
FOrmAT ( / 1 X, '
RETURN
END

ol,ll3 doesn't call anything')

oVlll calls ol;ll')

Return to ol,llll')

.type ovlS.for
SUBROUTINE o~llS
TYPE 1
FoRMAT(/lX,'
RETURN
END
.type 01,11 G. for
SUBROUTINE ol;lG
TYPE 1
FoRMAT(/lX,'
CAll ol.ll2B
TYPE 2
FoRMAT( / 1){,'
RETURN
END

o~llS

o~llG

doesn't call anything')

call s oVl2B')

Return to oVlG')

5-5

OVERLAYS
• COM PILE ol)lO ,ol.ll I ,ol.ll 2 ,ol/l3 ,ol.IU! ,ol.ll5 ,ol.llG
FORTRAN: ol)lO
oi/lt)
FORTRAN: DilL. I
ol/li
FORTRAN: ol/l2
ol/l2A
oVl2B
FORTRAN: oVl3
ol/l3
FORTRAN: OVU!
ol.lla
FORTRAN: ol/l5
ol.ll5
FORTRAN: ol/lG
oVlG
• R lINK
*TEST/loG/loGlEVEl:5
*/ERRoRlEVEl:5/NoINITIAl
*TEST lol.IERlAY
*TEST/MAP
*oSK:TEST/PLoT/PLTTYP:PRINTER
*oVLO,oVLI/LINK:TEST
[LNKLMN Loading IIlodule ol,lLO frOM file oSK:oI)LO.REL[10,3551 ,LINK5A]]
[LNKLMN Loading Module ol/Ll frolll file oSK:oI.IL1.REL[It),3551 ,LINK5A]]
[LNKLMN Loading Module ol.IRLAY fro~1 file SYS:oI.IRLAY.REL[1 ,5]]
[LNKLMN Loading ModlJle JoBoAT from file SYS:JoBoAT.REL[1 ,a]]
[LNKLMN Loading Module FoRINI from file SYS:FoRLIB.REL[l ,5]]
[LNKLMN Loading Module FoRDST frolll file SYS:FoRLIB.REL.[1 ,5]]
[LNKLMN Loading Module FoRPSE from file SYS:FoRLIB.REL[l ,5]]
[LNKELN End of link n'-tiliber
naille TEST]
*/NooE:TEST oI,lL2/LINK:LEFT
[LNKLMN Loading Module ol/L2A frolll file oSK:oI/L2.REL[10,3551 ,LINK5A]]
[LNKLMN LoadilH Itlodule ol/L2B froln file DSK:oI/L2.REL[10,3551 ,LINK5A]]
[LNKELN End of I inK nU~lbe r 1 naMe LEFT]
*/NoDE:LEFT oI,lL5/LINK:LEFT1
[LNKLMN Loading ~lodule DI,IL5 from file DSK:OI.ll5.REUIO,3551 ,LINK5A]]
[LNKELN End of I inK numbe r 2 name LEFT1]
*/NOoE:LEFT OI,lLG ILINK:LEFT2
[LNKLMN Loading Module OI.ILG from file DSK:OI.ILG.REL[IO,3551 ,LINK5A]]
[LNKELN End of linf( nUltlber 3 naille LEFT2]
*/NODE:TEST OI,lL3,OI,lLa/LINK:RIGHT
[LNKLMN Loading Module OI)L3 from file DSK:OI.IL3.REL[10,3551 ,LINK5A]]
[LNKLMN Loading ~Iodule OI,lLa from file DSK:OI)La.REL[10,3551 ,lINK5A]]
[LNKELN End of linf( nUlllber
naMe RIGHT]
*TEST ISSAt.JE
*/EXECUTE/GO
[LNKXCT OI,lLO execution]

Execution begins in main prograM OI.ILO
Qt.ILO CALLS Ol/L2A
OI.IL2A CALLS Ol,lL5
ol)L5 DOESN'T CALL AN'lTH I NG
RETURN TO OI.IL2A
ol.IL2A CALLS ol.ILG
ol.JL.G CALLS ot.I L2B
ol.IL2B DOESN'T CALL AN'lTH I NG
RETURN TO ol/LG
RETURN TO ol.IL2A
RETURN TO ol/LO
ol.ILO CALLS OI,lLa
OI/L.a CALLS DVL 1
ot.IL 1 CALLS ol/L3
oVL3 ~OESN'T CALL AN'lTH I NG
RETURN TO oVL 1
RETURN TO ol.ILI.!
RETURN TO OVL.O
Execution ends in Main prograM OI/LO

CPU tillie 0.32

Elapsed tiMe 0.95

EXIT

5-6

OVERLAYS
·TYPE TEST.LOG
12: 55: 15
6
12: 55: 15
6
12: 55: 16
6
6
12: 55: 16
12: 55: 16
6
6
12: 55: 16
6
12: 55: 16
7
12: 55: 19

LMN
LMN
LMN
LMN
LMN
LMN
LMN
ELN

Loadin!ll~odule OI.lLO from file DSK:OI,JLO.REL[10,3551 ,LINK5A]
Loadin91l10dule OVLl frolll file DSK:OI,JL1.REL[10,3551,LINK5A]
Loading module OI,JRLAY frOll1 file SYS:OI,JRLAY.REL[1 ,5]
Loadin!lmo,hlle JOBDAT frol,1 file SYS:JOBDAT.REL[1 ,1I]
Loading 1,lodule FORINI frolll file SYS:FORLIB.REL[I.5]
Loadin!llllodule FORDST frol,1 file SYS:FORLIB.REL[1 ,5]
Loadin!llllodule FORPSE frol,1 file SYS:FORLIB.REL[1 ,5]
End of 1 inf( nUI,lbe r 0 nal,le TEST

12: 55: 19
12: 55: 19
12:55:20

6
6
7

LMN
LMN
ELN

Loading 1,lodule Ol,lL2A frolll file OSK:OI,JL2.REL[10,3551 ,LINK5A]
Loadin!llllod'Jle Ol,JL2B frolll file DSK:Ql,JL2.REL[!0,3551 ,LINK5A]
End of linK nUI,lbe r 1 nallle LEFT

12:55:20
12:55:20

6
7

LMN
ELN

Loadin!ll'lodule OVL5 frolll file DSK:OVL5.REL[10,3551 ,LINK5A]
End of 1 inf( IHllllbe r 2 nallle LEFTI

12:55:20
12:55:20

LMN
ELN

Loadin!llllodule OVL6 from file DSK:OI,IL6.REL[10,3551,LINK5A]
End of linK IHllllber 3 nal,le LEFT2

12:55:21
12:55:21
12:55:21

LMN
LMN
ELN

Loadin!llllodule Ol,IL3 from file DSK:OI,lL3.REL[10,3551.LINK5A]
Loading mod'Jle Ol,lLlI from file DSK:OI,JLlI.REL[10,3551.LINK5A]
End of linK numbe r 1I nal,le RIGHT

• TYPE TEST. MAP
page
TEST IKLlKS
LINK symbol map of
Produced b}' LINK 'Jersion 5A(2030) on 17-Dec-82 at 12:55:23
TEST
Overla}' no.
0
Overla}' is absolute
o ends at
100211 len!lth
10025 =
9P
LO'N se!llllent starts at
7763. len!lth
32 (octal). 26. (decilllal)
Control Blocf( address is
1I91 '.'0 rds free in La'•• se!ll,lent
95 Global s}'I,lbols loaded. therefore 1,lin. hash size is 106
Start address is
235. located in pro!lral,1 OVLO

*************

OI.lLO

frOll1 DSK:OI,JLO.REL[10.3551.LINK5A
Lo',' segment starts at
1110 ends at
High segment starts at
235 ends at
MAIN.

Global

235

created b}' FORTRAN IKL/KS on 1I-Nov-82 at 15 00:00
2311 len!lth
75 (octal).
61. (dec l'lal)
3115 length
111 (octal>.
73. (dec 1,lal>
235 Entry Relocatable

OVLO

Relocatable

*************

OI,ILI

frOll1 DSK:OI,JL1.REL[10.3551.LINK5A]
LO'N segment starts at
3116 ends at
High seSlllent starts at
1I00 ends at
OVL1

1I01

Entfl'

created by FORTRAN IKL/KS on 1I-No.,'-82 at 111:1I7:00
377len!lth
32 (octal>.
26. (decimal)
1I112 len!lth
1I3 (octal).
35. (decimal)
FORon,

Relocatable

500010 Global Absolute

*************

OVRLAY

from SYS: OI.lRLAY. REU 1 .5]
LO'N segment starts at
High se'glllent starts at
CLROI) •
INIOI,J.
REMOI,J.
SAVOV.
.OVRLA
.OVRLU

2712
2570

26211
2665
5224

35111

2-Au!l-82
9: 18: 00
created b}' MACRO on
1001l (0 c tal) •
6226 1 en !It h
5223 ends at
(0
c tal) ,
1I11115
5107
1
en
!It
h
ends
at
1I113
En trY
En trY
Entry
En trY
Entry
En t fl'

GETOI,J.
LOGOI) •
RUNOV.
'X,OVRLA
.OI,JRLO
.OVRWA

Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable

2610 Ent ry Relocatable
2731 Entry Relocatable
26112 Entry Relocatable
Suppressed
501000201l Global Absolute
5302 Global Relocatable
5301 Global Relocatable

*************

JOBDAT

from SYS:JOBDAT.REUI ,1I]

created by MACRO on 26-FEB-81 at 19:25:00

Zero length Illodule

*************

5-7

516. ( dec i ilia 1 )

23111. (decimal>

OVERLAYS
FORINI

created by MACRO on 15-Sep-82 at 19:45:00
1040 ( 0 c t a I) ,
7476 I en !It h
6437 ends at
210 ( 0 c t a I) ,
6436 I en !It h
8227 ends at

from SYS:FORLI6.REUI ,5]
LOIN segment starts at
High segment starts at

Entry
Entry
Entry
En trY

6432
6402
6344
6362

ABORT.
ALCOR.
CLOSE:.
DEC.

LINK symbol map of

Re I ocatatol e
Relocatable
Relocatable
Relocatable

ALCHN.
CERPT.
DBMS.
DECHN.

TEST IKLlKS

page

Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable

ENC.
E){ITI.
FIND.
FOROP.
IF 1.
IN.
INQ.
MTHER.
NLI •
OPEN.
RESET.
TRACE.

544. ( dec i (,I a I)
136. ( dec i ma I)

6406
6437
6416
6410

Entry
Global
En t fl'
En trY

Relocatable
Relocatable
Relocatable
Relocatable

6360
6346
6376
8422
6424
6350
6420
6430
6364
6342
6227
6412

En t fl'
En t fl'
En trY
Entry
En t fl'
Entry
Entfl'
Entry
Entry
En trY
En t fl'
Entry

Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable
Relocatable

FORINI
En t fl'
Entry
En trY
Entry
En trY
En trY
En trY
Entry
Entry
En trY
En t fl'
En t rl'
Entry

6404
6400
6372
6340
6414
6426
6336
6370
6374
6366
6352
6354
6356

DECDR.
E}{IT f
FIN.
FORER.
FUNCT.
IFO.
INIT •
IOLST.
MTOP.
NLO.
OUT.
RTB.
WT6.

*************

FORDST

created by MACRO on 15-Sep-82 at 19:45:00
7477 I en !It h
1 ( 0 eta I) ,
7477 ends at

from SYS:FORLI6.REL[1 ,5]
High se!lment s t~a r t s at
DBSTP$

Entry

7477

1. ( dec i (,I a I)

Relocatable

******** *.~***

FORPSE

fro~l SYS:FORLIB.REL[1 ,5]
LOIN segment starts at
High segment starts at

7501

PAUS.

created by MACRO on 15-Sep-82 at 19:45:00
7702 ends at
7762len!lth
61 (octal),
49. (decimal)
7500 ends at
7701lenHh
202 (octal),
130. (deci(,lal)
Ent fI'

STDP.

Relocatable

7504 EntrY Relocatable

*************

Index to LINK symbol map ofoff'X,e
Name

Pol !Ie

Pa!le

Name
FORPSE
JOBDAT

FORDST
FORINI

LINK

SY~lbol

Name

Pol !Ie

Name

Pol !Ie

OIJRLAY

OIJLO
Ql.ILI

map of

page 3

TEST IKLlKS

pa!le 4

TEST IKLlKS

name
LEFT
Overlay no.
Overlay is absolute
14262len!lth
236 =
1P
14025 ends at
Low se!lment starts at
30 (octal), 24. (deci(,lal)
Control BlocK address is 14221, len9'th
Path is 0
333 INords free in Low se!lment
6 Global symbols loaded, therefore min. hash size is 7

*************

OlJL2A

from DSK:OIJL2.REU10.3551 ,LINK5A]
Low segment starts at
14025 ends at
14077 ends at
High segment starts at
OIJL2A

14100

Entry

created by FORTRAN IKL/KS on 4-NoIJ-82 at 14:47:00
14076len!lth
52 (octal),
42. (deci(tlal)
14173len!lth
75 (octal),
61. (deci~lal)

Relocatable

*************

OIJL2B

from DSK: OIJL2. REU 10,3551 ,LINK5A]
Low se!lment starts at
14174 ends at
14207 ends at
Hi!lh segment starts at
OIJL26

14210

Entry

created by FORTRAN IKL/KS on 4-NoIJ-82 at 14 47:00
14206lenHh
13 (octal),
11. (dec mal)
14220 length I
12 (octal) ,
10. (dec mal)

Relocatable

*************

5-8

OVERLAYS
LINK S}'hlbol map of

TEST IKLlKS

olJerla}' no.
name
LEFTI
overla}' is absolute
Low segment starts at
111263 ends at
1113116 length
611 =
1P
Control Block address is
111137, lenHh
20 (octal), 16. (decimal>
PathisOol
281 war d s f r e e in Low s e gm e n t
3 Global s}'mbols loaded, therefore min. hash size is 1I

*************

oVLS

from oSK:oVLS.REU10,3SSI ,LINKSAJ
Low segment starts at
111263 ends at
High segment starts at
111277 ends at
oVLS

111300

Ent r)'

created b}' FORTRAN IKL/KS on 1I-NoIJ-82 at 111:1I7:00
111276 length
III (octal).
12. (decimal>
111316 length
20 (octal).
16. (decimal)

Relocatable

*************

LINK symbol map of

pa ge 6

113

TEST IKLlKS

Overlay no.
3
name
LEFT2
olJerlal' is absolute
Low segment starts at
111263 ends at
11111117 length
16S =
lP
Control Block address is 1111120. len!lth
20 (octal). 16. (decimal)
PathisOol
216 '.10 rds free in Low segment
1I Global sl'mbols loaded. therefore min. hash size is S

*************

oVL6

from oSK:oVL6.REU10.3SSI ,LINKSAJ
Low segment starts at
111263 ends at
High segment starts at
111332 ends at
0~JL6

111333

En trY

created by FORTRAN IKL/KS on 1I-Nov-82 at 111:1I7:00
111331 length
1I7 (octal).
39. (decimal>
1111117 length
66 (octal).
SlI. (decimal>

Relocatable

*************

LINK symbol map of

TEST IKLlKS

Overlay no.
1I
name
RIGHT
o'!erlaY is absolute
Low segment starts at
111025 ends at
111207 length
163 =
IP
Control Block address is
22 (octal>. 16. (decimal)
111156. len!lth
Path is 0
376 wo rds free in Low se gment
5 Global symbols loaded. therefore hiln. hash size is 6

*************

oVL3

from oSK :0l.lL3. REU 10 .3551 .LINK5AJ
Low segment starts at
111025 ends at
High segment starts at
1110111 ends at
0l.lL3

lL101l2

Entry

created by FORTRAN IKL/KS on 1I-Nov-82 at 11l:L17:00
1110110 len!lth
III (octal>,
12. (decimal>
lL1060 length
20 (octal).
16. (decimal)

Relocatable

*************

ol.lLLI

from oSK:0l.lLLI.REU10.3551 .LINK5AJ
created by FORTRAN IKL/KS on L1-Nov-82 at ILl:L17:00
Low segment starts at
ILl061 ends at
111112 len!lth
32 (octal).
26. (decimal)
High segment starts at
lL1113 ends at
lL1155 len!lth
L13 (octal>.
35. (decimal>
oVLLI
ILlllL1
Entry
Relocatable

*************

page 8

Index to overlay number of TEXT IKL/KS
Overlay Pa!le

Over I a}' Page

Overlay Page

o'Jerlay Page

110
111

112

113

IILI

Page

Name

Page

3
LI

Index to overlay names of TEST
Name
LEFT
LEFTI

Pa !Ie

Name

Page

Name

LEFT2

RIGHT

[End of LINK map of

TEST

TEST]

5-9

OVERLAYS
The listing file TEST.OVL will look similar to the following:
o
TEST

4
RIGHT

3
LEFT2
MR-S-2596-83

5.2

WRITABLE OVERLAYS

Ordinarily each overlay link built by LINK is copied by the overlay
handler from the OVL file to the address space at runtime. The
contents of any locations that have been modified will be lost each
time the overlay link is copied from the OVL file. This can be
prevented by the use of writable overlays.
If a link is specified as writable, the overlay handler copies that
link to a temporary file on disk before overwriting it. Later, when
the copied link is needed, the overlay handler retrieves the link from
the temporary file rather than the OVL file.
In this way, any
modified values are preserved. Because writable overlays involve more
file I/O, they are slower than the default (nonwritable) overlays and
should only be used when the program
structure
and
storage
requirements demand dynamic storage in overlay links.

To specify that an overlay is writable, use the FORTRAN SAVE statement
in the program, and specify /OVERLAY:WRITABLE when loading the program
with LINK.

5.2.1

Writable Overlay Syntax

To build a writable overlay, specify the keyword
/OVERLAY switch in the LINK command line:

WRITABLE

with

the

filespec/OVERLAY:WRITABLE

5.2.2

Writable Overlay Error Messages

The overlay handler must write and update a temporary file.
In
addition to the error messages associated with all overlays, there are
two additional error messages for writable overlays:
?

OVLCWF Cannot write file [filename]:

[reason]

OVLCUF Cannot update file [filename]:

[reason]

If either of these messages appears, you should check for disk quota
violations or other conditions that could prevent the overlay handler
from writing a temporary file.
5-10

January 1985

OVERLAYS
5.3

RELOCATABLE OVERLAYS

LINK ordinarily allocates 2000 extra words at the end of the root link
and no extra space at the end of each subsequent link.
This is
adequate for programs with static storage requirements.
If a
link
requires extra storage at run-time, you can use the /SPACE switch to
make the necessary allowances for
the program's requirements.
The
/SPACE switch allows you to specify the number of words to be
allocated after the current link is loaded.
However,
there are
programs
whose
dynamic
run-time
storage
requirements are unpredictable.
For example, a program's run-time
storage requirements may vary according to the program's input.
For
this class of programs, relocatable overlays can be useful.
For relocatable overlays LINK places extra relocation information in
the OVL file,
permitting overlay links to be relocated at runtime.
The overlay handler, using the FUNCT. subroutine, can determine where
the link will fit
in the address space and resolve relocatable
addresses within the link.
This extra processing causes relocatable
overlays to run slower than nonrelocatable overlays.
Relocatable
overlays should only be used when you cannot determine the dynamic
storage requirements of a program.

5.3.1

Relocatable Overlay Syntax

To build a relocatable overlay, specify the RELOCATABLE keyword to the
/OVERLAY switch in the LINK command line:
filespec/OVERLAY:RELOCATABLE

5.3.2

Relocatable Overlay Messages

If /OVERLAY: (LOGFILE,RELOCATABLE) is specified during the loading of a
program,
informa~ional messages of the following form are sent to the
user's terminal:
%OVLRLL Relocating link [linkname] at [address]

5-11

OVERLAYS
5.4

RESTRICTIONS ON OVERLAYS

The following restrictions apply to all overlayed programs:
•

Overlayed programs cannot be run execute-only.

•

PSECTed programs cannot be overlayed.

•

Overlayed programs with large buffer
requirements must use
the /SPACE switch.
If an %OVLMAN (Memory not available)
error is encountered, the program should be reloaded using
the /SPACE switch with each link.

•

If the program uses more than 256 links,
use the /MAXNODE
switch to specify the number of links necessary for the
program.
LINK will allocate extra space in the the OVL file
for
tables that require it, based on the number of links you
specify.

5.4.1

Restrictions on Absolute Overlays

The following restrictions apply to absolute overlaid programs:
1.

Any intermediate results stored in non-root links are lost as
soon as the links are overlaid.
Do not expect to retain a
value stored in a non-root link unless /OVERLAY:WRITABLE has
been specified.

Certain forms of global,
inter-overlay references are not
recommended because you cannot be sure that the necessary
modules will be in memory at the right time.
Some of these
references are:
•

Additive fixups, in the form FOO##+BAR where
another overlay.

FOO

•

Left-hand fixups, in the form XWD FOO##,BAR, where FOO is
in another overlay.

•

Fullword fixups, in the form EXP FOO##, where FOO
another overlay.

•

Similarly, MOVEI 1,FOO##, where FOO is in a different
overlay, should not be used, because the necessary module
may not be in memory.

In fact, the only predictable inter-overlay global
reference
is one that brings the necessary module into memory, such as
PUSHJ P,FOO##.

5-12

OVERLAYS
5.4.2

Restrictions on Relocatable Overlays

The following restriction applies to relocatable overlays:
•

Complex expressions involving relocatable symbols are not
relocated properly in a relocatable overlay.
No standard DEC
compiler produces such expressions.
MACRO programmers should
avoid using them in subroutines that are to be loaded as part
of an overlayed program.
Any expression that causes MACRO to
generate a Polish fixup block will not be properly relocated
at runtime.
The following
are examples of such complex
expressions:
such a complex expression:
MOVEI 1,A## + B## + C##
A, ,0

5.4.3

Restrictions on FORTRAN Overlays

The following restriction applies to FORTRAN programs that are written
with associate variables and using the overlay facility.
•

If the associate variable is declared in a subroutine,
that
subroutine must be loaded in the root link of the overlay
structure.
Accessing a file opened with an
associate
variable changes the value of the specified variablE~.
If
this variable is in a nonresident overlay link when the
access is made, program execution will produce unpredictable
results.
Moreover, the value of the variable will be reset
to zero each time its overlay link is removed from memory.
Only variables declared in routines that are loaded into the
root link will always be resident.
However,
variables
declared in COMMON and in the root link will always be
resident, and may be safely used as associate variables.

•

If you place COMMON in a writable overlay, be sure that all
references to the variables in that COMMON are in the same
overlay or its successors.

•

A FORTRAN ASSIGN statement may be used
in a
relocatable
overlay.
If the ASSIGN is made in a subroutine, the value of
the assigned variable may be preserved from one call of that
subroutine to the next.
However, the overlay containing that
subroutine could then be replaced in memory by a different
overlay.
If the overlay containing the subroutine is
relocated differently when brought back into memory, any
subsequent GOTO may fail.

5-13

OVERLAYS
5.5

SIZE OF OVERLAY PROGRAMS

Although most programs have a consistent size, the size of an overlay
program depends on which overlays are
in memory.
This can be
ascertained by using the /COUNTER switch when linking the program.
To
do this,
place /COUNTER after
the /LINK switch for the overlay of
which you want to know the size, but before the next /NODE switch.
This will give you the size of the program when the overlay is
actually loaded into memory.
The display will
include all
routines
loaded from the runtime libraries.
This allows you to determine which
overlay is the largest, and whether the program can be loaded without
restructuring.

5.6

DEBUGGING OVERLAYED PROGRAMS

COBDDT and ALGDDT can be used to debug overlay programs,
but FORDDT
cannot.
To use DDT with an overlaid program, the program should be
loaded using /SYMSEG:LOW, with local symbols for the desired modules.
To set breakpoints in an overlay, put a subroutine in the root node,
and call the subroutine from the overlay.
Such a subroutine need
consist only of a SUBROUTINE statement, a RETURN,
and an END.
The
breakpoint can be set at this subroutine before the program starts
running.
When a FORTRAN program starts running, it calls RESET.
in FOROTS,
which
removes the symbol table.
The symbol table will return after
the first overlay is called.
If you need the symbols for debugging
the root link,
insert a CALL INIOVL at the beginning of the main
program (refer to Section 5.7.1 for more information).
This call will
reinstall
the symbol table.
LINK builds a separate symbol table for
each overlay, so that all the symbols known to DDT are for modules
that are currently in memory.
Note that it is not possible to
single-step through RESET.
($X and $$X will not work).
Set a
breakpoint after RESET.
if you are debugging a root link, and use $G.

5.7

THE OVERLAY HANDLER

LINK's overlay handler is the program that supervises
overlay structures defined by LINK switches.

execution

When you load an overlay structure, the overlay handler is loaded into
the
root link of the structure.
From there it can supervise
overlaying operations, because the root link is always in your virtual
address space during execution.
During execution, when a link not in
memory is called, the overlay handler brings
in the link, possibly
overlaying one or more links already in memory.

5-14

OVERLAYS
The overlay handler consists of self-modifying code and data, and
two
128-word buffers.
One of these buffers, IDXBFR, contains a 128-word
section of the link number index table.
This allows 256 links to be
directly referenGed at anyone time.
The second buffer, INBFR,
contains the preambles and relocation tables,
if required,
of the
individual links.
There are two ways of overlaying links during execution:

5.7.1

A call to a link not in memory implicitly calls the overlay
handler to overlay one or more links with the required links.
This action of the overlay handler
is transparent to the
user.

An explicit call to one of several entry points
in the
overlay handler can cause one or more links to be overlaid.
These entry points and calls to them are discussed
in the
sections below.

Calls to the Overlay Handler

Overlays can be used transparently, or they can be explicitly called
from
the program.
Such calls are made to one of the entry points in
the overlay handler.
The overlay handler has five entry points that are available for calls
from user programs.
To call the overlay handler from a MACRO program,
you must use the standard calling sequence, which is:
MOVEI
PUSHJ

I
I

16,arglst
17,entry-name

Where arglst is the address of the
first
argument
list, and entry-name is the entry-point name.

the

argument

The argument list must be of the form:

-n, ,0
arglst:

Z code,addrl

in is number of arguments
iFor first argument

Z code,addrn

iFor nth argument

Where addr •..

is the address of the argument.

The legal values of "code" are 2 (for a link number), 17 (for an ASCIZ
string), and 15 (for a character string descriptor).
For each word of the argument list, the code
indicates the type of
argument.
The code occupies the AC field, bits 9 through 1:2.
The
address gives the location of the argumenti
it can be indirect and
indexed.
To call the overlay handler from a FORTRAN program, the call
of the form:

must

Where subroutine is the name of the desired subroutine, and arglst
a list of arguments separated by commas.

CALL subroutine (arglst)

5-15

OVERLAYS
5.7.2

Overlay Handler Subroutines

Each of the seven callable subroutines in the overlay handler has an
entry name symbol for use with MACRO, and a subroutine name for use
with FORTRAN, as follows:

MACRO Entry
Name Symbol

FORTRAN
Subroutine

Subroutine
Function

CLROV.

CLROVL

Specifies a non-writable overlay.

GETOV.

GETOVL

Brings specified links into memory.

INIOV.

INIOVL

Specifies the file from which the overlay
program will be read,
if the load time
specification is to be overridden.

LOGOV.

LOGOVL

Specifies or closes the file
in which
runtime messages from the overlay handler
will be written.

REMOV.

REMOVL

Removes specified links from memory.

RUNOV.

RUNOVL

Moves into memory a specified link
begins execution at its start address.

SAVOV.

SAVOVL

Specifies a writable overlay.

and

Declaring a Non-Writable Link (CLROV.)
You can declare an overlay link to be non-writable, using the CLROV.
entry point. This does not immediately affect the program, but waits
until the link is about to be overlaid or read in.
If the link is
already non-writable, this entry point has no effect.
Example
MOVEI
PUSHJ
arglst:

l6,arglst
l7,CLROV.

-n, , a
Z l7,addrl

;n is number of arguments
;for first ASCIZ linkname

Z l7,addrn

;for nth ASCIZ linkname
OR

arglst:

-n, , a
Z 2,addrl

;n is number of arguments
;for first link number

Z 2,addrn

;for nth link number

Where addr .•.

is the address of the argument.

5-16

OVERLAYS
Getting a Specific Path (GETOV.)
The subroutine to bring a specific path into core can be used to make
sure that a particular path is used when otherwise the overlay handler
might have a choice of paths.
It is illegal to specify a path that
overlays the calling link.

To call the subroutine from a FORTRAN program, use:
CALL GETOVL (linkname, •.. ,linkname)
where each linkname is the ASCIZ name of a link in the desired path.
To call the subroutine from a MACRO program, use the standard
calling sequence:
MOVEI
PUSHJ

FORTRAN

16,arglst
17,GETOV.

The argument list has one word for each link required
path.

the

Example
arglst:

-n, ,0
Z l7,addrl

;n is number of arguments

Z 17,addrn
OR
arglst:

-n, ,0
Z 2,addrl

;n is number of arguments

Z 2,addrn
Where addr •••

is the address of the argument.

Initializing an Overlay (INIOV.)
The overlay initializing subroutine specifies a file
from which the
overlay program will be read.
This sdbroutine is used to override the
file specified at load time.
The file specified to INIOV. can have
any valid specification, but it must be in the correct format for an
overlay (OVL) file.
To call the subroutine from a FORTRAN program, use:

CALL INIOVL ('filespec')
where 'filespec' is a literal constant that can give a device,
filen~me, a file type, and a project-programmer number (PPN).
To call the subroutine from a MACRO program, use the standard
calling sequence:
MOVEI
PUSHJ

16,arglst
17,INIOV.

5-17

FORTRAN

OVERLAYS
The argument list is of the form:
-1, ,0
arglst: Z 17,address of ASCIZ filespec

where filespec is an ASCIZ string (ASCII ending with nulls)
give a device, a filename, a file type, and a PPN

that

can

NOTE
If you call INIOV. with no arguments, it
initiates the overlay handler and reads
in the symbols for the root link,
using
the 6verlay file specified at load time.
This can be useful
for debugging
the
root link before any successor links
have been read in, because symbols are
not normally available until the first
link comes into memory.
Specifying an Overlay Log File (LOGOV.)
You can specify an output file for runtime messages from the overlay
The log file
handler.
These messages are
listed
in Section 5.5.
to the
entry includes the elapsed run time since the first call
overlay handler.
To call this subroutine from a FORTRAN program, use:

I
I

CALL LOGOVL ('filespec')
where 'filespec' is a literal constant
filename, a file type, and a PPN.

that

can

give

device,

To close the file, use
CALL LOGOVL (0)
To call the subroutine from a MACRO program, use the standard
calling sequence:

FORTRAN

16,arglst
17,LOGOV.
The argument list is of the form:
-1, ,0
arglst: Z 17,address of ASCIZ filespec

Where filespec is an ASCIZ string that can give a device, a
a file type, and a PPN.
To close the log file, the argument list is:
-1 , ,0
arglst: Z 17,address of word containing zero

5-18

filename,

OVERLAYS
Removing Specific Links from Memory (REMOV.)
The subroutine to remove specific links from memory, once they are no
longer
required,
can be used
to reduce core image size for faster
execution.
Specifying removal of the calling link causes an error.

To call the subroutine from a FORTRAN program, use:
CALL REMOVL (linkname, ••• ,linkname)
Where each linkname is the ASCIZ name of a link
memory.

removed

To call the subroutine from a MACRO program, use the standard
calling sequence:
MOVEI
PUSHJ

from

FORTRAN

l6,arglst
l7,REMOV.

The argument list has one word for each link to be removed.
Example

-n, ,0
arglst:

;n is number of arguments

Z 17,addrl

Z l7,addrn
OR
arglst:

-n, ,0
Z 2,addl

;n is number of arguments

Z 2,addrn
Where addr •..

is the address of the argument.

Running a Specific Link

(RUNOV.)

The subroutine for running a specific link allows you to transfer
program execution to the start address of a particular link.
(An
error occurs if the link has no start address.)
If the link
is not
already in memory, it and its path are brought in.
You can use this subroutine to overlay the calling link,
because the
next instruction executed
is the start address of the named link;
therefore, there is no automatic return to the calling link.
NOTE
The FORTRAN compiler does not generate
start
addresses
for
subroutines.
FORTRAN main programs cannot be loaded
into non-root links.
Therefore, to use
RUNOVL to transfer control to a
FORTRAN
subroutine in a non-root link, you must
use the /START switch at load
time to
define a start address for the link.

5-19

OVERLAYS
To call the subroutine RUNOVL from a FORTRAN program, use:
CALL RUNOVL (linkname)
Where linkname is the ASCIZ name of the link to be run.
To call the subroutine from a MACRO program, use the standard
calling sequence:
MOVEI
PUSHJ

FORTRAN

l6,arglst
l7,RUNOV.

The argument list is of the form:
-1, ,0

arglst: Z l7,address of ASCIZ linkname
OR
-1, ,0

arglst: Z 2,address of link number
Declaring A Writable Link (SAVOV.)
You can dynamically declare an overlay link to be writable by calling
SAVOV.
This
does not affect the current state of the code
immediately, but waits until the link is about to be overlaid. If the
link already writable, this symbol has no effect.
Example
MOVEr
PUSHJ

arglst:

l6,arglst
l7,SAVOV.
is number of arguments

-n, ,0

Z l7,addrl

ifor first ASCIZ linkname

Z l7,addrn

ifOr nth ASCIZ linkname
OR

arglist:

is number of arguments
ifor first link number

-n, ,0
Z 2,addrl

Z 2, addrn

ifOr nth link number

Where addr ••.

is the address of the argument.

If called with no arguments, SAVOV.
file.

5-20

only

initializes

the

temporary

OVERLAYS
5.7.3

Overlay Handler Messages

This section lists all of the overlay handler's messages.
(The
messages from LINK, which have the LNK prefix, are given in Appendix
B. )

For each overlay handler message,
the last three letters of the
six-letter code,
the severity, and the text of the message are given
in boldface.
Then, in lightface type, comes an explanation of the
message.
When a message is issued,
the three letters are suffixed to
letters OVL,
forming a 6-letter code of the form OVLxxx.
explanation of the message will be printed only if you us':,
/OVERLAY:LOG switch.

the
The
the

The severity of a message determines whether
the job will be
terminated when the message is issued.
Level 31 messages terminate
program execution.
Level 8 messages are warnings:
they do not
terminate execution,
but the error may affect the execution of the
program.
Levell messages are informational and are printed on the
terminal only if you specified /OVERLAY:LOGFILE.
Code

Sev

ARC

Message and Explanation
Attempt to remove caller from link [name or number]
The named link attempted to remove the link that called
it.
This error occurs when the call to the REMOV.
subroutine requests removal of the calling link.

ARL

Ambiguous request in link number
using link number [number]

[number]

for

[symbol],

More than one successor
link satisfies a call
from a
predecessor
link, and none of these successors is in
memory.
Since all their paths are of equal
length,
the
overlay handler has selected an arbitrary link.
CCF

COL

Cannot close file [file], status [octal]
For some reason, the overlay handler cannot close
its working files.
This is a file I/O error.

one

Cannot delete link [name or number], FUNCT. return
[number]

status

This is an internal LINK error, and
is not expected to
occur.
If
it
does,
please notify your Software
Specialist, or send a Software Performance Report (SPR) to
DIGITAL.
Return status is one of the following:
1

3
CFF

Core already deallocated
Illegal argument passed to FUNCT. module

Cannot find file [file]

[reason]

The overlay handler has attempted, unsuccessfully, to open
an EXE, OVL, or .TMP file.

5-21

OVERLAYS
Code

Sev

CGM

Message and Explanation
Cannot get memory from OTS, FUNCT. return status [octal]
The system does not have enough free memory to load the
overlay link.
The status is returned from the object-time
system, and depends on the particular FUNCT. function that
the overlay handler used.
See Section 5.7.4 for the
FUNCT. function codes and status messages.

CRF

Cannot read file [file]

[reason]

An error occurred when reading the overlay file.
The file
was closed after the last successful read operation.
CSM

Cannot shrink memory, FUNCT. return status [octal]
A request to the object-time system to reduce memory,
if
possible,
failed.
This error is not expected to occur.
If it does, please notify your Software Specialist or send
a Software Performance Report (SPR) to DIGITAL.

CUF

Cannot update file [file]

[reason]

An error occurred when updating the TMP file
into
non-resident writable overlay links are written.
CWF

Cannot write file [file]

which

[reason]

An error occurred when creating the TMP file used to store
non-resident writable overlay links.
DLN

Deleting link [name or number] after [hh:mm:ss]
The named
a call to
since the
is output

IAT

link has been removed from memory as a result of
the REMOV. subroutine.
The time is elapsed time
first call to the overlay handler.
This message
only to the overlay log file, if any.

Illegal argument type on call to [subroutine]
A user call to the named overlay handler
an illegal type of argument.

IEF

subroutine

gave

Input error for file [file], status [octal]
An error occurred while reading the OVL or TMP file.

ILN

Illegal link number [number]
A user call to one of the overlay handler subroutines gave
an illegal Link number as an argument.

IMP

Impossible error condition at PC=[address]
This is an internal error caused by monitor call error
returns that should not occur.
This message is issued
instead of the HALT message.
This error is not expected
to occur.
If it does,
please notify your Software
Specialist or send a Software Performance Report (SPR)
to
DIGITAL.

IPE

Input positioning error for file [file], status [octal]
An error occurred while reading the OVL or TMP file.
5-22

January 1985

OVERLAYS
Code

Sev

IVN

Message and Explanation
Inconsistent version numbers
The OVL and EXE files found were not created at
time, and may not be compatible.

LNM

the

same

Link number [decimal] not in memory
A call to the REMOV.
subroutine has removed the named
link from memory.
It must be restored by a call to GETOV.
or RUNOV.

MAN

Memory not available for
status [octal]

absolute

[link],

FUNCT. return

There is not enough room for the overlay handler to load
the specified link into the part of memory th~ link was
built for.
Two options are available:
a) Use the /SPACE
switch at load time to reserve more space for the link, or
b) Build a
relocatable overlay using the RELOCATABLE
option to the /OVERLAY switch at load time.
MEF

Memory expansion failed, FUNCT. return status [octal]
The overlay handler was unable to get free space from the
memory manager.
Restructure your overlay so that the
minimum number of links are in memory at any time.

NMS

NRS

Not enough memory to load symbols, FUNCT.
[octal]

return

status

There was not enough free space available to load
into memory.

symbols

No relocation table for symbols
A relocation table was not included for the symbol table.
It is possible that LINK failed to load the relocation
table because there wasn't enough room in memory.

NSA

No start address for link [name or number]
A user call to the RUNOV. subroutine requests execution to
continue at the start address of the named link, but that
link has no start address.

NSD

No such device for [file]
An invalid device was specified.

OEF

Output error for file [file], status [octal]
An error occurred when writing the overlay file.
The file
was closed after the last successful write operation.

OPE

Output positioning error for file [file], status [bctal]
An error occurred while writing the TMP file used to
non-resident writable overlay links.

5-23

hold

OVERLAYS
Code

Sev

RLL

Message and Explanation
Relocating link [name or number] at [address]
The named relocatable link has been loaded at the given
address.
This message is output only to the overlay log
file.

RLN

Reading in link [name or number] after [time]
The named link has been loaded.
The time given is elapsed
time since the first call to the overlay handler.
This
message is output only to the overlay log file.

STS

OTS reserved space too small
The object-time system does not have space for its minimum
number of buffers.
Reload, using the /SPACE switch for
the root link with an argument greater than 2000 (octal).

ULN

Unknown link name [name]
A call to one of the overlay handler subroutines gave
invalid link name as an argument.
Correct the call.

USC

Undefined subroutine [name] called from [address]
A required subroutine was not loaded.
The instruction at
the given program counter address calls for an undefined
subroutine.
Correct the call or load the
required
subroutine.

WLN

Writing [link] after [time]
The overlay handler is
link.

5.7.4

writing

out

writable

overlay

The FUNCT. Subroutine

Each DIGITAL-supplied object-time system has a subroutine that the
overlay handler uses for memory management, I/O, and message handling.
This subroutine has a single entry point, FUNCT., and is called by the
sequence:
MOVEI
PUSHJ

l6,arglst
l7,FUNCT.

The format of the argument list is:
-<n+3>,,0
arglst: Z 2,address of integer function code
Z 2,address for error code on return
Z 2,address for status code on return
Z code,address of first argument

Z code,address of nth argument

5-24

OVERLAYS
Where function code is one of the function codes described below;
error code is a 3-letter ASCII mnemonic output by the object-time
system (after ?, %, or [); and status (on return) contains one of the
following values:
-1

Function not implemented
Successful return
Number of the error message

Most object-time systems allocate separate space for their own use and
for the use of the overlay handler. This minimizes the possibility
that the overlay handler will request space that the object-time
system is already using.
The permitted function code arguments, their names, and their meanings
are:
Code

Name

Function

ILL

Illegal function;

GAD

Get a specific segment of memory.

COR

Get a given amount of memory from anywhere
space allocated to the overlay handler.

RAD

Return a specific segment of memory.

GCH

Get an I/O

RCH

Return an I/O channel.

GOT

Get memory from the
object-time system.

returns -1 status.

the

ROT

Return memory to the object-time system.

RNT

Get the initial runtime, in milliseconds, from
object-time system.

the

IFS

Get the initial runtime file specification
program being run.

the

CBC

Cut back core (if possible) to reduce job size.

F.RRS

Read retain status (DBMS)

F.WRS

Write retain status

F.GPG

Get pages

F.RPG

Return pages

F.GPSI

Get TOPS-20 PSI channel

F.RPSI

Return TOPS-20 PSI channel

All FUNCT.

channel~

space

allocated

(DB~S)

codes are reserved to DEC.

The
following
subsections
describe
each
function
FUNCT. subroutine (except the reserved functions).

5-25

the

OVERLAYS
ILL (0)

Function

This function is illegal.
status returned is -1.
GAD (1)

The

argument

list

ignored,

and

the

Function

The GAD function gets memory from a specific address in the
allocated to the overlay handler. The argument list points to:
arg 1
arg 2

space

Address of requested memory
Size of requested allocation (in words)

A call to GAD with arg 2 equal to -1 requests all available memory.
On return, the status is one of the following:

1
2
3

COR (2)

Successful allocation
Not enough memory available
Memory not available at specified address
Illegal arguments (address + size > 256K)
Function

The COR function gets memory from any available space allocated to the
overlay handler. The arguments are:
arg I
arg 2

Undefined (address of allocated memory on return)
Size of requested allocation

On return, the status is:

o
1
3
RAD (3)

Core allocated
Not enough memory available
Illegal argument (size > 256K)
Function

The RAD function returns the memory starting at the specified
to the overlay handler. The arguments are:
arg 1
arg 2

Address of memory to be returned
Size of memory to be returned (in words)

On return, the status is one of the following:

o
1
3

Successful return of memory
Memory cannot be returned
Illegal argument (address or size > 256K)

5-26

address

OVERLAYS
GOT (6)

Function

The GOT function gets memory from the
object-time system.
Its arguments are:
arg 1
arg 2

space

allocated

the

Undefined (address of allocated memory on return)
Size of memory requested

On return, the status is one of the following:

o
1
3

ROT (7)

Successful allocation
Not enough memory available
Illegal argument (size> 256K)
Function

The ROT function
arguments are:
arg 1
arg 2

returns

memory

the

object-time

system.

Its

Address of memory to be returned
Size of memory to be returned (in words)

On return, the status is one of the following:

o
1
3

Successful return of memory
Memory cannot be returned
Illegal argument (address or size> 256K)

RNT (10)

Function

The RNT function returns the initial runtime,
in milliseconds,
from
the object-time system.
(At the beginning of the program, the
object-time system will have executed a RUNTIM UUO:
the result is the
time returned by RNT.)
Its arguments are:
arg 1
arg 2

Undefined
Ignored

(contains initial runtime on return)

On return, the runtime is in arg 1, and the status is
is O.
IFS (11)

The

status

Function

The IFS function returns the initial runtime file specification from
the object-time system.
(This initial file specification is the one
used to begin the program:
that is, it was given with a compile-class
command.) Its arguments are:
arg 1
arg 2
arg 3

Undefined (SIXBIT device on return)
Undefined (SIXBIT filename on return)
Undefined (project-programmer number on return)

On return, the status is one of the following:

o Successful return
1

Error

5-27

OVERLAYS
CBC (12)

Function

The CBC function cuts back memory if possible, which reduces the
of the job.
It uses no arguments, and the returned status is o.

size

RRS (13) Function ( Reserved for DBMS )
Returns ARGI = O.

On return, the status is always O.

WRS (14) Function ( Reserved for DBMS )
Returns ARGI
GPG

= O.

On return, the status is always O.

(15) Function

The GPG function is used to fetch a page.
arg2:

The arguments are:

size to be allocated, in words

On return,
argl = address of allocated memory, on page boundary
and the status is one of the following:

o if allocated OK
1 if not enough memory
3 if argument error
RPG

(16) Function

The RPG function is used to return pages.
argl:
arg2:

The arguments are:

address (a word)
size (in ,,,ords)

On return, the status is:
o if deallocated OK
1 if wasn't allocated
3 if argument error
GPSI

(17)

The GPSI function can be
running
in a TOPS-20
controlled access to the
exist and
that SIR and
other JSYS necessary to
exampl e) .

used to get a PSI channel
for programs
environment.
This entry point provides only
PSI tables.
It will arrange that the tables
EIR have been done but does not do AIC or any
(ATI or MTOPR,
set up the channel
for

The arguments are:
argl: channel number,
or -1 to allocate any user-assignable channel
arg2: level number
arg3: address of interrupt routine

5-28

OVERLAYS
On return, arg1 contains the channel number allocated
originally specified).
On return, the status is:

(if

-1

was

o if OK
1 if channel was already assigned
2 if no free channels
3 if argument error
NOTE
This function is used by TOPS-20
programs.
It is a reserved function in
the TOPS-10 environment.
RPSI

(20) Function

This entry point provides only controlled access to the PSI tables.
It does not do DIC or any other JSYS necessary to release a channel.
It just clears the level and interrupt address fields in CHNTAB.
This function accepts the following argument:
arg1:
channel number
On return the status is one of the following:
o if OK
1 if channel wasn't in use
3 if argument error
NOTE
This function is used by TOPS-20
programs.
It is a reserved function in
the TOPS-10 environment.

5-29

OVERLAYS
5.8

THE OVERLAY (OVL) FILE

This section contains diagrams of the contents of the
output by LINK as a
result of the /OVERLAY switch.
diagram shows the overall scheme of the file:

overlay file
The following

Scheme of the Overlay (OVL) File

=======================================================1
1

Directory Block

1
1

=======================================================1

Link Number Table

=======================================================1

Link Name Table

1
1

=======================================================1

writable Link Flags Table

1
1

=======================================================1

Link

-------------------------------------------------------I

I-----------------~-------------------------------------I
1
1
1

Link

I
1
I=========~=============================================1

5-30

OVERLAYS
5.8.1

The Directory Block

The following diagram shows the contents of the Directory Block:
Directory Block
.DIHDR:
.DIRGN:
.DIVER:
.DILPT:
.DINPT:
.DIWPT:
.DIFLG:

1=======================================================1
1
0 (Reserved)
1 Length of Directory Block 1
1-------------------------------------------------------I
1
0 (Reserved)
1
1-------------------------------------------------------I
1
Version Number of Corresponding EXE file
1
1-------------------------------------------------------I
1 -(Size of Link No. Table) ILink Number Table Block No.1
1-------------------------------------------------------I
I-(Size of Link Name Table) 1 Link Name Table Block No.1
1-------------------------------------------------------I
I-(Size of Writable FIg Tbl) 1 Writable FIg Tbl Block No 1
1-------------------------------------------------------I
1
Flags
1
1-------------------------------------------------------I
1
0 (Reserved)
1
1=======================================================1

In the fourth word above, the size of the Link Number Table (in words)
is half the number of links (rounded upward);
the Link Number Table
Block No. is the number of the 128-word disk block containing the Link
Number Table.
(There are four disk blocks per disk page.)
In ~he fifth word above, the size of the Link Name Table (in words) is
twice the number of links;
the Link Name Table Block No. is the
number of the 128-word disk block containing the Link Name Table.
The table defined by the .DIWPT word above consists of a string of
two-bit
bytes.
The first bit, OW.WRT,
indicates whether the
corresponding overlay link is writable.
This bit is set under the
control of a REL block of type 1045 (writable links).
The second bit,
OW.PAG, indicates whether the corresponding overlay link is currently
paged into the runtime overlay temporary file.
This is strictly a
run-time flag and should be zero in the overlay file.
This flag
is
defined in the overlay file to allow the overlay handler to set up its
flag table with a single read operation.
The .DIFLG word in the directory block contains a single bit flag (bit
0) .
If this bit is set the overlay file contains at least one
writable overlay.
This information is also contained in the Writable
Link Table.
However,
by having the information available in the
directory block the overlay handler can determine if any links are
writable without scanning the Writable Link Table.
All other bits in
the .DIFLG word are reserved and must be zero.
NOTE
If a user requests both writable and
relocatable
overlays,
only halfwords
known to be relocatable at load time
will be correctly relocated when the
link is refetched.

5-31

OVERLAYS
5.8.2

The Link Number Table

The following diagram shows the contents of the Link Number Table:
Link Number Table

1=======================================================1
1
Pointer to Link 0
1
Pointer to Link 1
1
1-------------------------------------------------------I
1
Pointer to Link 2
1
Pointer to Link 3
1

1-------------------------------------------------------I

1
Pointer to Link n-l
1
Pointer to Link n
1
1=======================================================1
Each pointer is a disk block number. Any unused
disk block of the Link Number Table are zeros.

5.8.3

words

the

last

The Link Name Table

The following diagram shows the contents of the Link Name Table:
Link Name Table

1=======================================================1
1

Link Number

1-------------------------------------------------------I
1
SIXBIT Link Name
1
1=======================================================1

1=======================================================1
1

Link Number

1-------------------------------------------------------I
1
SIXBIT Link Name
1
1=======================================================1

Any unused words in the last disk block of the
zeros.

5-32

Link

Name

Table

are

OVERLAYS

5.8.4

The Overlay Link

The following diagram shows the overall scheme of each overlay link in
the overlay file:
Scheme of an Overlay Link

=======================================================1
1

Preamble

=======================================================1

Code for Link

1
1

=======================================================1
Link Control Section

1
1
1

=======================================================1

EXTTAB

1
1

=======================================================1

INTTAB

1
1

=======================================================1

Relocation Table

1
1

=======================================================1

Other Relocation Tables

1
1

=======================================================1

5-33

OVERLAYS
The Preamble
The following diagram shows
overlay link:

the

contents

the

preamble

for

Preamble

1=======================================================1
1
a (Reserved)
1
Length of Preamble
1
1------------------------------------------------------1
a (Reserved)
1
a (Reserved)
1------------------------------------------------------1
a (Reserved)
1
Link Number

1------------------------------------------------------SIXBIT Link Name
1------------------------------------------------------IPointer to List of Bound Links Starting with Root Link
1------------------------------------------------------Pointer to List of Bound Links Ending with Root Link
1------------------------------------------------------Equivalence Pointer
1------------------------------------------------------Address of Control Section
1-------------------------------------------------------I
1
Flags
1
1-------------------------------------------------------I
Absolute Address at Which Link Loaded
1-------------------------------------------------------I
1
Length of Link (Code through INTTAB)
1
1-------------------------------------------------------I
Disk Block Number of Start of Link Code'
1-------------------------------------------------------I
a (Reserved)
1-------------------------------------------------------I
Disk Block Number of Relocation Table
1------------------------------------------------------Disk Block Number of Other Relocation Tables
1------------------------------------------------------a (Reserved)
1------------------------------------------------------Disk Block Number of Radix-50 Symbols
1------------------------------------------------------IBlock Number of Relocation Tables for Radix-50 Symbols
1------------------------------------------------------Next Free Memory Location for Next Link
1

1
1

1=======================================================

5-34

OVERLAYS
Code for the Link
The code for each link consists of a core image that was constructed
from the REL files placed in the link.
This core image contains the
code and data for the link.
The Control Section
The following diagram shows the contents of the Control Section:
Control Section

1=======================================================1
1
0 (Reserved)
1
Length of Header
1
1-------------------------------------------------------I
1
0 (Reserved)
1
0 (Reserved)
1
1-------------------------------------------------------I
1
0 (Reserved)
1
Link Number
1

1-------------------------------------------------------I
SIXBIT Link Name
1-------------------------------------------------------I
1 Ptr to Ancestor in Core 1 Ptr to Successor in Core 1
1-------------------------------------------------------I
1 - (Length of Symbol Table) 1 Address of Symbol Table 1
1-------------------------------------------------------I
o (Reserved)
Start Address for Link
-------------------------------------------------------I
Memory Needed to Load Link
First Address in Link
-------------------------------------------------------I
- (Length of EXTTAB)
1
Pointer to EXTTAB
1
-------------------------------------------------------I
- (Length of INTTAB)
Po inter to INTTAB
-------------------------------------------------------I
Address of Symbols on Disk
-------------------------------------------------------I
Relocation Address
-------------------------------------------------------I
Copy of Block Number for Code
-------------------------------------------------------I
-(Length of Radix-50 SymTab) IBlk No. of Radix-50 SymTabl
1

1
1

=======================================================1

5-35

OVERLAYS
The EXTTAB Table
The following diagram shows the contents of the EXTTAB table:
EXTTAB

1=======================================================1
JSP 1,.OVRLA

1-------------------------------------------------------I
Flags
IAddress of Callee's INTTAB
1-------------------------------------------------------I
Callee's Link Number
IPtr to Callee's Control Secl
1-------------------------------------------------------I
1
Backward Pointer
1
Forward Pointer
1
1

1=======================================================1
1=======================================================1
JSP l,.OVRLA

1=======================================================1

The flags in the left half of
meanings:

the

second

word

Bit

Meaning (if bit is on)

Module is in core.
Module is in more than one link.
Relocatable link is already relocated.

I
2

5-36

have

the

following

OVERLAYS
The INTTAB Table
The following diagram shows the contents of the INTTAB table:
INTTAB

1=======================================================1
1
0 (Reserved)
1 Address of Entry Point
1

1-------------------------------------------------------I

1
0 (Reserved)
1
Forward Pointer
1
1=======================================================1
1=======================================================1
1
0 (Reserved)
1 Address of Entry Point
1

1-------------------------------------------------------I

1
0 (Reserved)
1
Forward Pointer
1
1=======================================================1

5-37

OVERLAYS
The Relocation Table
The following diagram shows the contents of the Relocation Table:
Relocation Table

1=======================================================1
1

Relocation Word

1-------------------------------------------------------I

1-------------------------------------------------------I
Relocation Word
1

1=======================================================1

The Relocation Table contains one bit for each halfword of the link.
If the bit is on,
the halfword is relocatable;
if it is off, the
halfword is not relocatable.
The first word contains the relocation bits for the first
22
(octal)
words of the 'link;
the second word contains the relocation bits for
the next 22 (octal) words;
and so forth for all words in the link.
This table exists only when relocatable overlays
the jOVERLAY:RELOCATABLE switch.

5-38

are

requested

with

OVERLAYS
The Other Relocation Tables
The following diagram shows
Tables:

the

contents

the

Other

Relocation

Other Relocation Tables
I===========================================~===========1
Number of Words Following for This Link
1

1-------------------------------------------------------I
1
Link Number
1 Planned Load Address
1
1-------------------------------------------------------I
1
Relocation Halfword
1 Ptr to Words of Code
1
1-------------------------------------------------------I
1-------------------------------------------------------I
1
Relocation Halfword
1 Ptr to Words of Code
1
1=======================================================1
1=======================================================1
1
Number of Words Following for This Link
1
1-------------------------------------------------------I
1
Link Number
1 Planned Load Address
1
1-------------------------------------------------------I
1
Relocation Halfword
1 Ptr to Words of Code
1
1-------------------------------------------------------I
1-------------------------------------------------------I
1
Relocation Halfword
1 Ptr to Words of Code
1
1=======================================================1
This table exists only when relocatable overlays have been requested
with the OVERLAY/RELOCATABLE switch.
The Other Relocation Tables are
used to hold internal LINK references.

5-39

CHAPTER 6
PSECTs

PSECTs (Program SECTions) are programmer- or system-defined regions of
code and data that LINK relocates in memory.
PSECTs are used to
structure a program's memory space, or to load a program that uses
extended addressing.

6.1

LOADING PROGRAMS WITH PSECTs

When loading programs with PSECTs, you must specify the or1g1n of the
PSECT.
LINK then uses this PSECT origin to store the data in the
PSECTs.
To specify a PSECT origin, include the origin in the source program or
use the LINK /SET switch.
See the appropriate language manual for
including the origin in the source program and Chapter 3 for the /SET
switch.
Defining an upper bound is also important when loading PSECTs.
The
LINK /LIMIT switch defines an upper bound for a PSECT.
If the PSECT
loads to this bound, LINK returns a warning and an error message.
Despite these messages, LINK continues to process input files and to
load code. The warning is:
%LNKPEL PSECT [psect] exceeded limit of [address]
Although LINK does continue to process input files and load code,
the
program is incomplete and should not be used.
LINK does issue the
following fatal error:
--?LNKCFS Chained fixups have been suppressed
Chained fixups
references.

are

method

Using /LIMIT to define an
overlaps.
PSECT overlaps
unpredictable behavior.

that

LINK

uses

resolve

symbol

upper bound prevents dgintended PSECT
can cause LINK to loop and produce other

For example, the LRGPRO and BIGPRO modules each contain two PSECTs,
BIG and GRAND.
LRGPRO is loaded and /COUNTERS is used to check PSECT
origins and current values.
PSECT origins are found by looking under
the initial value column and PSECT current values are found by looking
under the current value column of the /COUNTERS output.
The upper
bound is found by looking under the limit value column •
• R LINK ~
*/SET:BIG:1000 ~
*/SET:GRAND: 5400 ~
*LRGPRO ~
6-1

April 1986

PSECTs
* /COUNTERS ~
[LNKRLC Reloc. ctr.
.LOW.
BIG
GRAND

initial value

1000
5400

current value
140
5100
10500

limit value
1000000
1000000
1000000]

*
/COUNTERS shows that the current value for PSECT BIG and the initial
value for PSECT GRAND are close together in memory. The current value
for BIG is 5100 and the PSECT origin for GRAND is 5400.
The /LIMIT
switch can now be used to restrict PSECT BIG's current value to PSECT
GRAND's initial value using the following:
*/LIMIT:BIG:GRAND~

/LIMIT prevents an unintended overlap because it causes LINK to issue
a warning if the current value for BIG exceeds GRAND's origin. The
warning is:
%LNKPEL PSECT [psect] exceeded limit of [address]
The warning message indicates' that the PSECTs overlaped, and that
PSECTs BIG and GRAND need to be farther apart in memory. The
/COUNTERS switch shows a new current value greater than 5400.
Notice
that the limit set with the /LIMIT switch is shown in the limit value
column.
*BIGPROG£)
%LNKPEL PSECT BIG exceeded limit of 5400
detected in module .MAIN from file DSK:BIGPRO.REL[12,3456]
*/COUNTERS~

[LNKRLC Reloc. ctr.
.LOW.
BIG
GRAND

initial value

1000
5400

current value
140
6300
10500

limit value
1000000
5400
1000000]

/GO continues loading the program, and LINK issues a warning and fatal
error message.
The warning is:
%LNKPOV Psects [psect] and [psect] overlap from address
[address]

[address]

The fatal error message is:
?LNKCFS chained fixups have been suppressed
For example,
*/GO~

%LNKPOV Psects BIG and GRAND overlap from address 5400 to 6300
?LNKCFS chained fixups have been suppressed
EXIT
Now, LINK is re-run and the PSECTs are moved farther apart in
In this example, GRAND's origin is reset from 5400 to 7000 •

memory.

• R LINK0!D

*/SET:BIG:I000~

*/SET:GRAND: 7000 ~
*LRGPRO~

6-2

January 1985

PSECTs
*/COUNTERS ~
[LNKRLC Reloc. ctr.
.LOW.
BIG
GRAND
*
*/LIMIT:BIG:GRAND ~
*BIGPRO ~
*/COUNTERS ~
[LNKRLC Reloc. ctr.
.LOW.
BIG
GRAND

initial value
0
1000
7000

current value
140
5100
10500

limit value
1000000
1000000
1000000]

initial value
0
1000
7000

current value
140
6300
10500

limit value
1000000
5400
1000000]

*/GO~

EXIT

6.2

PSECT ATTRIBUTES

PSECT attributes specify how LINK stores a PSECT in
page access of the PSECT.

memory,

The CONCATENATED or
PSECTs.

how

6.2.1

OVERLAID

attribute

specifies

and

LINK

the

stores

CONCATENATED and OVERLAID

LINK uses the CONCATENATED or OVERLAID attributes when loading PSECTs
into memory. These attributes are specified when the PSECT is defined
in the source program, and are contained in REL Blocks 24 and 1050.
See Appendix A for information on these blocks.
If the attribute is
not specified, LINK uses CONCATENATED.
The following example illustrates how PSECTs are stored in memory.
In
this example, modules MAINKO and MAINKC contain three PSECTs, ALPHA,
BETA, and GAMMA. There is an additional module named SUBMD1.
The
ALPHA and BETA PSECTs have the CONCATENATE attribute. The GAMMA
PSECT, which is a data PSECT declared in each module, has the OVERLAID
attribute defined in MAINKO and the CONCATENATE attribute defined in
MAINKC.
First, LINK is run and the origin is set for PSECTs ALPHA,
GAMMA •

BETA,

and

• R LINK ~
*/SET:ALPHA:3000/SET:BETA:5000/SET:GAMMA:7000 ~
Next, MAINKO is loaded with GAMMA defined as OVERLAID, and
is used to display the initial, current, and limit values.
*MAINKO ; OVERLAID GAMMA ~
* /COUNTERS ~
[LNKRLC Reloc. ctr.
initial value
.LOW.
0
ALPHA
3000
BETA
5000
GAMMA
7000
6-3

current value
140
3017
5011
7025

/COUNTERS

limit value
1000000
1000000
1000000
1000000]
April 1986

PSECTs
Now, SUBMDl is loaded, /COUNTERS is used, and /GO is used to load
modules and exit LINK.

the

Notice that the current values for ALPHA and BETA have increased,
that the current value for GAMMA remains the same.

and

*SUBMD1~

* /COUNTERS G!D
[LNKRLC Reloc. ctr.
.LOW.
ALPHA
BETA
GAMMA
*/GOG!!)

initial value

3000
5000
7000

current value
140
3033
5041
7025

limit value
1000000
1000000
1000000
1000000]

EXIT

In the following example, LINK is run and the origin is set for PSECTs
ALPHA, BETA, and GAMMA •
• R LINK G!D

*/SET:ALPHA:3000/SET:BETA:5000/SET:GAMMA:7000~

Now, MAINKC is loaded with GAMMA defined as CONCATENATE, and /COUNTERS
is used.
*MAINKC
;CONCATENATED GAMMA@)
* /COUNTERS G!D
[LNKRLC Reloc. ctr.
initial value
current value
.LOW.
o
140
ALPHA
3000
3017
BETA
5000
5011
GAMMA
7000
7025

limit value
1000000
1000000
1000000
1000000]

*
Next, SUBMDl is loaded, /COUNTERS is used, and /GO is used to load the
modules and exit LINK.
Notice that all current values have increased.
*SUBMDl G!D
* /COUNTERS ~
[LNKRLC Reloc. ctr.
.LOW.
ALPHA
BETA
GAMMA

initial value

3000
5000
7000

*/GO~

current value
140
3033
5041
7035

limit value
1000000
1000000
1000000
1000000]

EXIT

•

6-4

April 1986

PSECTs
6.2.2

RWRITE

The RWRITE attribute sets the page access for
PSECTs to
read/write.
This attribute can be set in the source program or omitted, as RWRITE
is the default.
For example, the following MACRO statement defines
for the ALL PSECT •

read/write

access

• PSECT ALL/RWRITE,IOOO
1000 is the PSECT's origin.
NOTE
The RONLY attribute does exist for compatibility with
MACRO-20 and LINK-20, but is not recommended for use
on TOPS-IO.
You should not use RONLY on TOPS-IO
because TOPS-IO does not support read-only pages in
the low-segment and LINK considers PSECTs to be part
of the low segment.
LINK does build an .EXE file from
.REL files that have
the RONLY attribute set,
but
these files cannot be run on TOPS-IO.

6-5

January 1985

APPENDIX A
REL BLOCKS

The object modules that LINK loads are output from the language
translators.
These
object
modules
are
formatted
into REL
(RELocatable) Blocks, each of which contains information for LINK.
This appendix describes each type of REL Block and gives its
Terms used throughout this discussion are defined as follows:
Header Word: a fullword giving the REL Block Type in its
and a short count or long count in its right half.

format.

left

half

Short Count: a halfword giving the length of the REL Block, excluding
relocation words
(which appear before each group of 18
decimal, or 22 octal words), and excluding the header word.
Long Count: a halfword giving the length of the REL Block,
including
all words in the block except the header word itself.
Relocation Word: a fullword containing the relocation bits for up to
18 decimal or 22 octal words following words. Each relocation
bit is either 1, indicating a relocatable halfword, or 0,
indicating a nonrelocatable halfword.
The first two relocation bits give the relocatability of the
left and right halves, respectively, of the next following
word; the next two bits give the relocatability of the two
halves of the second following word; and so forth for all bits
in the word, except any unused bits, which will be zero.
If a REL Block has relocation words, the first one follows the
header word. If more than 18 (decimal) data words follow this
relocation word, the next word (after the 18 words) is another
relocation word. Thus, a REL Block that has relocation words
will have one for each 18 words of data that it contains.
If
the REL Block does not contain an integral multiple of 18
words, the last relocation word will have unused bits.
NOTE
A block with a zero short
include a relocation word.
Data Word:
MBZ:

count

does

not

Any word other than a header word or a relocation word.

Must Be Zero.
NOTE
All numbers in this appendix
specifically noted as decimal.
A-I

are

octal

unless

January 1985

REL BLOCKS

The diagram below shows a REL Block having a short count of 7,
relocation word.

Block Type

and

Relocation Word
Data Word 1
Data Word 2
Data Word 3
Data Word 4
Data Word 5
Data Word 6
Data Word 7
=======================================================

The diagram below shows a REL Block having a short count of 31 and two
relocation words.

1=======================================================1
1
Block Type
1
31
1

1-------------------------------------------------------I
1
Relocation Word
1
1-------------------------------------------------------I
1
Data Word 1
1
1-------------------------------------------------------I

1-------------------------------------------------------I
1
Data Word 22
1
1-------------------------------------------------------I
1
Relocation Word
1
1-------------------------------------------------------I
1
Data Word 23
1
1-------------------------------------------------------I
1-------------------------------------------------------I
1

Data Word 31

A-2

January 1985

1=======================================================1

REL BLOCKS
REL Block Types must be numbered
in the
range 0 to 777777.
The
following list shows which numbers are reserved for DIGITAL, and which
for customers:
Use

Type Numbers

o40
100
402
600
700
1000
2000
4000

37
77
401
577
677
777
1777
3777
- 777777

Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved

A-3

for
for
for
for
for
for
for
for
for

DIGITAL
customers
DIGITAL
customers
customer files
DIGITAL files
DIGITAL
customers
ASCII text

January 1985

REL BLOCKS
Block Type 0 (Ignored)

1=======================================================1
1

Short Count

1-------------------------------------------------------I
1
Relocation Word
1
I--------------------------~----------------------------I

Data Word

1-------------------------------------------------------I

1-------------------------------------------------------I
Data Word
I

1=======================================================1

Block Type

a is ignored by LINK.

If the short count is 0, then no
block consists of only one word.
in a REL file.

relocation word follows,
and the
This is how LINK bypasses zero words

A-4

January 1985

REL BLOCKS
Block Type 1 (Code)

1=======================================================1
1
1
1
Short Count
1

1-------------------------------------------------------I
Relocation Word
1
1-------------------------------------------------------I
1
Data Word
1
1-------------------------------------------------------I
1

1-------------------------------------------------------I
Data Word

1=======================================================1

Block Type 1 contains data and code.
The first data word gives the
address at which the data
is to be loaded.
This address can be
relocatable or absolute, depending on the value of bit 1 of the
relocation word.
The remaining data words are loaded beginning at
that address.
If the start address is given in symbolic,
Block Type 1 is used:

the

following

format

1=======================================================1
1

Short Count

1-------------------------------------------------------I
1
Relocation Word
1
1-------------------------------------------------------I
1
Symbol
1
1-------------------------------------------------------I
1
Offset
1
1-------------------------------------------------------I
1-------------------------------------------------------I
1
Data Word
1
1-------------------------------------------------------I
In this alternate format, the first four bits of the first data word
(Symbol)
are 1100 (binary), and the word is assumed to be a Radix-50
symbol of type 60.
The load address is calculated by adding the value
of the global symbol to the offset given in the following word.
The
third and following data words are loaded beginning at the resulting
address.
The global symbol must be defined when the Type 1 Block is
found.

A-5

January 1985

REL BLOCKS
Block Type 2 (Symbols)

1=======================================================1
1
2
1
Short Count
1

1-------------------------------------------------------I
1
Relocation Word
1
1-------------------------------------------------------I
ICode 1
Radix-50 Symbol
1
1-------------------------------------------------------I
1
Second Word of Pair
1
1-------------------------------------------------------I
1-------------------------------------------------------I
ICode 1
Radix-50 Symbol
1
1-------------------------------------------------------I
1
Second Word of Pair
1
1=======================================================1

The first word of each pair has a code in bits a to 3 and a Radix-50
symbol in bits 4 to 35 (decimal). The contents of the second word of
a pair depends on the given code. The octal codes and their meanings
are:
Code

Meaning

This code is illegal in a symbol block.

The given symbol is a global definition. Its value, contained
in the second word of the pair, is available to other programs.

The given symbol is a local definition, and its value is
contained in the second word of the pair.
If the symbol is
followed by one of the special pairs or by a Polish REL Block
(as explained below, under code 24), the symbol is considered a
partially defined local symbol. Otherwise, it is considered
fully defined.

The given symbol is a block name (from a translator that uses
block structure).
The second word of the pair contains the
block level. The symbol is considered local; if local symbols
are loaded,
the value of the block name is entered in the
symbol table as its block level.

The given symbol is a global definition. However, it is only
partially defined at this time, and LINK cannot yet use its
value. If the symbol is defined in terms of another symbol,
then the next entry in the REL file must be a word pair in a
Block Type 2 as follows:

1=======================================================1
1 60 1
Other Symbol
1

1·-------------------------------------------------------I
1 50 1
Th i s Symbol
1
1=======================================================1

In this format, code 50 indicates that the right
word depends on the other symbol.

A-6

half

the

January 1985

REL BLOCKS
Code

Meaning
If the partially defined symbol is defined in terms of a Polish
expression, then the next entry in the REL file must be Block
Type 11 (Polish), whose store operator gives this symbol as the
symbol to be fixed up. A fixup resolves the symbol. The store
operator must be -4 or -6.

The given symbol is a global definition. However, it is only
partially defined at this time, and LINK cannot yet use its
value.
If the symbol is defined in terms of another symbol,
then the next entry in the REL file must be a word pair in a
Block Type 2 as follows:

1=======================================================1
1 60 1
'Other Symbol
1
1-------------------------------------------------------I
1 70 1
This Symbol
1
1=======================================================1
In this format, code 70 indicates that the
word depends on the other symbol.

left

half

the

If the partially defined symbol is defined in terms of a Polish
expression, then the next entry in the REL file must be Block
Type 11 (POLISH), whose store operator gives this symbol as the
symbol to be fixed up. The store operator must be -5.
34

1=======================================================1
1 60 1
Other Symbol
1
1-------------------------------------------------------I
1 50 1
This Symbol
1

1-------------------------------------------------------I
60
Other Symbol
1-------------------------------------------------------I
1 70
1
This Symbol
1
1

1=======================================================1

This format indicates that both halves of the
the other symbol.

depend

The given symbol is a global definition exactly as in code
except that it is not output by DDT.

04,

The given symbol is a local symbol exactly
except that it is not output by DDT.

The given symbol is a global request. LINK's handling of the
symbol depends on the value of the code in the first four bits
of the second word of the pair. These codes and their meanings
are:
00

word

code

10,

The right half of the word gives the address of the
first word in a chain of requests for the global memory
address. In each request, the right half of the word
gives the address of the next request. The chain ends
when the address is o.

A-7

January 1985

REL BLOCKS
Code

Meaning
40

The right half of the word contains an address.
The
right half of the value of the requested symbol is added
to the right half of this word.

The rest of the word contains a Radix-50 symbol whose
value depends on the requested global symbol.
(If the
given Radix-50 symbol is not the one defined
in the
previous word pair,
then this word is ignored.)
When
the value of the requested symbol
is resolved,
it is
added to the
right half of the value of the Radix-50
symbol.

The right half of the word contains an address.
The
right half of the value of the requested symbol is added
to the left half of this word.

The rest of the word contains a Radix-50 symbol whose
value depends on the requested global symbol.
(If the
given Radix-50 symbol is not the one defined
in the
previous word pair,
then this word is ignored.)
When
the value of the requested global symbol is resolved, it
is added
to the left half of the value of the Radix-50
symbol.

The given symbol is a global definition exactly as in code
except that it is not output by DDT.

24,

The given symbol is partially defined, where the left half is
deferred, as in code 30, except that it is not output by DDT.

The given symbol is partially defined, where the right half
is
deferred, as in code 34, except that it is not output by DDT.

Symbols are placed in the symbol table in the order that LINK finds
them.
However, DDT expects to find the symbols in a specific order.
For a non-block-structured program, that order is:
Program Name
Symbols for Program
For a block-structured program whose structure is:
Begin Block 1 (same as program name)
Begin Block 2
End Block 2
Begin Block 3
Begin Block 4
End Block 4
End Block 3
End Block 1

A-8

January 1985

REL BLOCKS

the order is:
Program Name (Block 1)
Block Name 2
Symbols for Block 2
Block Name 4
Symbols for Block 4
Block Name 3
Symbols for Block 3
Block Name 1
Symbols for Block 1
This ordering follows the rule that the name and symbols for each
block must occur in the symbol table in the order of the block endings
in the program.
NOTES
1.

Only one fixup by a Type 2, la, 11, or 12 Block is
allowed for a given field.
(There can be separate
fixups for the left and right halves of the same
word. )

Fixups are not necessarily performed in the
LINK finds them.

A-9

order

January 1985

REL BLOCKS
Block Type 3 (HISEG)

1=======================================================1
1

Short Count

1-------------------------------------------------------I
1
Relocation Word
1
1-------------------------------------------------------I
IHigh-Segment Program Break 1
High-Segment Origin
1
1-------------------------------------------------------I
1 (Low-Segment Program Break) 1
(Low-Segment Origin)
1
1=======================================================1

Block Type 3 tells LINK that code
segment.

loaded

into

the

high

Short Count is either I or 2.
If the left half of the first data word is 0, subsequent Type I blocks
found are assumed to have been produced by the MACRO pseudo-op HISEG.
This usage is not recommended. It means that the addresses in the
blocks are relative to 0, but are to be placed in the program high
segment. The right half of the first data word is the beginning of
the high segment (usually 400000).
(the preferred
If the left half of the first data word is nonzero
usage), subsequent Type I
blocks found are assumed to have been
produced by the MACRO pseudo-op TWOSEG.
The right half is interpreted as the beginning of the high segment,
and the left half is the high-segment break; the high-segment length
is the difference of the left and right halves.
(One-pass translators that cannot calculate the high-segment
should set the left half equal to the right half.)

break

If the second word appears in the HISEG block, its left half shows the
low-segment program break, and its right half shows the low-segment
origin (usually 0).

A-IO

January 1985

REL BLOCKS
Block Type 4 (Entry)

1=======================================================1
1

Short Count

1-------------------------------------------------------I
Relocation Word (Zero)
1-------------------------------------------------------I
Radix-50 Symbol
1

I----------------------------~--------------------------I

1-------------------------------------------------------I
1
Radix-50 Symbol
1
1=======================================================1

Block Type 4 lists the entry name symbols for a program module.
If a
Type 4 block appears in a module, it must be the first block in the
module.
A library file contains a Type 4 block for
each of
its
modules.
When LINK is in library search mode, the symbols
in the block are
compared to the current list of global requests for the load.
If one
or more matches occur, the module is loaded and the name of the module
is marked as an entry point in map files, etc.
If no match occurs,
the module is not loaded.
If LINK is not in library search mode, no comparison of requests and
entry names is made, and the module is always loaded.
Refer to Block
Type 17 for more information about libraries.
Refer to block type 14.

A-II

January 1985

REL BLOCKS
Block Type 5 (End)

1=======================================================1
1
5
1
Short Count
1

1-------------------------------------------------------I
1
Relocation Word
1
1-------------------------------------------------------I
1
First Data Word
1
1-------------------------------------------------------I
1
(Second Data Word)
1
1=======================================================1

Block Type 5 ends a program module.
A Block Type
encountered earlier in the module than the Type 5 block.

must

Short Count is 1 or 2.
If the module contains a two-segment program, the first data word
is
the high-segment break and the second data word is the low-segment
break.
If the module contains a one-segment program, the first data
word
is the program break and the second data word is the absolute
break.
If count is 1, then second word is assumed to be o.
Each PRGEND pseudo-op in a MACRO program generates a Type 5 REL block.
Therefore a REL file may contain more than one Type 5 block.
A library REL file has a Type 5 block
modules.

A-12

the

end

each

its

January 1985

REL BLOCKS
Block Type 6 (Name)

1=======================================================1
1
6
1
Short Count
1

1-------------------------------------------------------I
Relocation Word
1-------------------------------------------------------I
Radix-50 Symbol
1-------------------------------------------------------I
1 (CPU) 1
(Compiler)
1 (Length of Blank Common) 1
1-------------------------------------------------------I
1

Block Type 6 contains the program name, and must precede any Type 2
blocks.
(A module should begin with a Type 6 block and end with a
Type 5 block.)

Short Count is 1 or 2.
The first data word is the program name in Radix-50 format; this name
cannot be blanks. The second data word is optional; if it appears, it
contains CPU codes in bits 0 to 5, a compiler code in bits 6 to 17
(decimal),
and the length of the program's blank COMMON in the right
halfword.
The CPU codes specify processors for program execution as:
Bit
Bit
Bit
Bit

2
3
4
5

KSIO
KLIO
KIlO

KAIO

If all these bits are off, then any of the processors can be used
execution.
The compiler code specifies the compiler that produced the
The defined codes are:
0
1
2
3
4
5
6

Unknown
Not used
COBOL-68
ALGOL
NELIAC
PL/I
BLISS

7
10
11
12
13
14
15

SAIL
FORTRAN
MACRO
FAIL
BCPL
MIDAS
SIMULA

A-13

16
17
20
21
22
23
24
25

REL

for
file.

COBOL-74
COBOL
BLISS-36
BASIC
SITGO
(Reserved)
PASCAL
JOVIAL

January 1985

REL BLOCKS
Block Type 7 (Start)

I==================~==================~=================1
1
7
1
Short Count
1

1-------------------------------------------------------I
1
Relocation Word
1
1-------------------------------------------------------I
1
Start Address
1
1-------------------------------------------------------I
1 (60)

(Optional Radix-50 Symbol)

I============================~=======================~~=I

Block Type 7 contains the start address for program execution.
LINK
uses the start address in the last such block processed by the load,
unless /START or /NOSTART switches specify otherwise.
Short Count is 1 or 2.
If the second (optional) word is present, it must be a Radix-50 symbol
with the code 60; LINK forms the start address by adding the value of
the symbol to the value in the right half of the preceding word (Start
Address)
II

LINK builds an entry vector if it is specified or non-zero.

LINK V6.0

A-l4

April 1986

REL BLOCKS
Block Type 10 (Internal Request)

1=======================================================1
1
10
1
Short Count
1

1-------------------------------------------------------I
Relocation Word
1-------------------------------------------------------I
1 Pointer to Last Request 1
Value
1
1-------------------------------------------------------I
1

1-------------------------------------------------------I
1 Pointer to Last Request 1
Value
1
1-------------------------------------------------------I
Block Type 10 is generated by one-pass compilers to
resolve
requests
caused by forward references to internal symbols. The MACRO assembler
also generates Type 10 blocks to resolve requests for
labels defined
in literals; a separate chain is required for each PSECT in a PSECTed
program.
Each data word contains one request for an internal symbol. The left
half is the address of the last request for a given symbol.
The right
half is the value of the symbol.
The right half of the last request
contains the address of the next-to-last request, and so on, until a
zero right half is found.
(This is exactly analogous to Radix-50 code
60 with second-word code 00 in a Block Type 2.)
If a data word contains -1, then the following word contains a request
for
the left (rather than right) half of the specified word.
In this
case, the left half of r.he word being fixed up contains the address of
the next-to-last left half request, and so on, until a zero left half
is found.
(This is a left half chain analogous to the
right half
chain described above.)
NOTES
1.

Only one fixup by a Type 2,
10,
11, or
12
is
allowed for a given field.
(There can be separate
fixups for the left and right halves of the same
word.)

Fixups are not necessarily performed in the
LINK finds them.

A-IS

order

January 1985

REL BLOCKS
Block Type 11 (Polish)

1=======================================================1
11

Short Count

1-------------------------------------------------------I
1
Relocation Word
1
1-------------------------------------------------------I
Data Halfword
Data Halfword
1-------------------------------------------------------I
1

1-------------------------------------------------------I
I
Data Halfword
1
Data Halfword
1
1=======================================================1

Block Type 11 defines Polish fixups
for operations on relocatable
values or external symbols. Only one store operator code can appear
in a Block Type 11; this store operator code can be either a symbol
fixup code or a chained fixup code. The store operator code appears
at the end of the block.
NOTES

Only one fixup by a Type 2, 10, 11, or 12 Block is
allowed for a given field.
(There can be separate
fixups for the left and right halves of the same
word. )

Fixups are not necessarily performed in the
LINK finds them.

order

The data words of a Type 11 block form one Polish string of halfwords.
Each halfword contains one of the following:
1.

A symbol fixup store operator code.
A symbol fixup defines the value to be stored in the value
field of the symbol table for the given symbol. A symbol
fixup store operator code is followed by two or four data
halfwords.

A chained fixup store operator code.
A chained fixup takes a relocatable address whose corrected
virtual address
is the location for storing or chaining. A
chained fixup store operator code is followed by one data
halfword.

A data type code.
Data type code 0 is followed by a data
halfword;
a data type code 1 or 2 is followed by two data
halfwords.

An arithmetic or logical operator code.

A-16

ua nuary

1985

REL BLOCKS

A PSECT index code. This code defines a PSECT index to be
used for calculating the relocated addresses that appear in
this block.
PSECT indexes are needed only for PSECTed
programs.
A global PSECT index"is associated with a Block Type 11.
This index appears as the first halfword after the relocation
word, and it defines the PSECT for the store address or store
symbol. Any addresses for a different PSECT must be preceded
by a different PSECT index.
Thus, a relocatable data halfword in a different
appear in one of the following formats:

PSECT

must

1-------------------------------------------------------I
400nnn
(operator code)
1-------------------------------------------------------I
(operands)
1-------------------------------------------------------I
1

1-------------------------------------------------------I
I
1
400nnn
1
1-------------------------------------------------------I
(operator code)
(operands)
1-------------------------------------------------------I
1

where the different PSECT index is nnn+l.
Any relocatable address that does not have an explicit
preceding PSECT index code preceding its data type code is
assumed to be in the same PSECT as the store address for the
block.
The current PSECT may be set by a previous REL Block
type.
6.

A halfword of data {preceded by a data type o halfword)
or
two halfwords of data
(preceded by a data type 1 or 2
halfword) •
A sequence of halfwords containing a data type code 0
data halfword can begin in either half of a word.

and

The codes and their meanings are:
Symbol Fixup Store Operator Codes:
-7

Fullword replacement.

No chaining is done.

-6

Fullword symbol fixup.
The following one or two words
contain the Radix-SO symbol{s)
(with their 4-bit codes).
The first is the symbol to be fixed up, and the second is
the
block name for a block-structured program (O or
nonexistent for other programs).

A-17

January 1985

REL BLOCKS

-5

two words
Left half symbol fixup.
The following one or
The first is the symbol to be
contain the Radix-50 symbols.
is the block name
for
a
fixed up,
and the second
(0 or nonexistent
for other
block-structured
program
programs) •

-4

Right half symbol fixup.
The following one or
two words
contain the Radix-50 symbols.
The first is the symbol to be
fixed
up,
and the second
is
the block name
for
a
block-structured
program
(0 or nonexistent for
other
programs) •

Chained Fixup Store Operator Codes:

-3

Fullword chained fixup.
The halfword following
points to
the first element in the chain.
The entire word pointed to
is replaced, and the old right half points to the next
fullword.

-2

Left half chained fixup.
The halfword following
the first element in the chain.

points

-1

Right half chained fixup.
The halfword following points
the first element in the chain.

Data Type Codes:

The next halfword is an operand.

The next two halfwords form a fullword operand.

The next two halfwords form a Radix-50 symbol
that
is
global request.
The operand is the value of the symbol.

Arithmetic and Logical Operator Codes:
NOTE
Operands are
encountered.

read

the

order

that

they

are

Add.

Subtract.

Multiply.

Divide.

Logical AND.

Logical OR.

Logical shift.
(A positive second operand causes a shift to
the left.
A negative operand causes a shift to the right.)

Logical XOR.

Logical NOT (one's complement).

A-18

January 1985

REL BLOCKS
14

Arithmetic negation (two's complement).

Count leading zeros (like JFFO instruction).
Refer to the
MACRO Assembler Reference Manual for information about the
~L operand, which this code implements.

Remainder.

Magnitude.

Maximum.

Minimum.

Comparison.
Returns 0 if the two operands are different; -1
if they are equal.

Used to resolve the links in a chain.
12.

Symbol definition test.
Returns 0 if the operand
(a
Radix-50 symbol) is unknown; 1 if it is known but undefined;
-1 if it is known and defined.

Skip N words of Polish.

Skip N words of Polish on some condition.

Return contents of location N.

Refer to

Block

Type

PSECT Index Codes:
400nnn

PSECT index nnn, where nnn is a 3-digit octal integer.

For an example of a Type 11 block, the MACRO statements
EXTERN B
EXP <A*B+A)

Generate (assuming that A has a relocatable value of zero):
=======================================================

001011001001101101

3 (Add)

5 (Multiply)

o (Halfword Operand Next)

o (Relocatable)

2 (Fullword Radix-50 Next)

1st Half of Radix-50 B

2nd Half of Radix-50 B

1 0 (Halfword Operand Next)

o (Relocatable)

1-3 (Rh Chained Fixup Next)

0 (Chain Starts at 0')

1=======================================================

The first word contains the block type (11) and the short count
(6).
The second word
is the relocation word; it shows that the following
halfwords are to be relocated:
right half of second following word,
left half of fifth following word, left half of sixth following word.

A-19

January 1985

REL BLOCKS

The next word shows that the two operations to be performed are
addition and multiplication; because this is in Polish prefix format,
the multiplication is to be performed on the first two operands first,
then addition is performed on the product and the third operand.
The next two halfwords define the first operand. The first halfword
is a data type code 0, showing that the operand is a single halfword;
the next halfword is the operand (relocatable 0).
The next three halfwords define the second operand.
The first of
these halfwords contains a data type code 2, showing that the operand
is two halfwords containing a Radix-50 symbol with code 60. The next
two halfwords give the symbol (B).
The next two halfwords define the third operand. The first of these
halfwords contains a data type code 0, showing that the operand is a
single halfword; the next halfword gives the value of the operand
(relocatable 0).
The next two halfwords give the store operator for the block.
The
first of these halfwords contains the chained fixup store operator
code -3, showing that a fullword chained fixup is required; the next
halfword contains the operand (relocatable 0), showing that the chain
starts at relocatable zero.
The last halfword is irrelevant, and should be zero.
LINK issues the LNKJPB error message.

A-20

not,

January 1985

REL BLOCKS
Block Type 12 (Chain)

1=======================================================1
1

Short Count

1-------------------------------------------------------I
1
Relocation Word
1
1-------------------------------------------------------I
1
Chain Number
1
1-------------------------------------------------------I
Chain Address
Store Address
1-------------------------------------------------------I
1

1-------------------------------------------------------I
1
Chain Number
1
1-------------------------------------------------------I
Chain Address
Store Address
1

1=======================================================1

Block Type 12 chains together data structures from separately compiled
modules.
(The MACRO pseudo-ops
.LINK and .LNKEND generate Type 12
blocks.) Block Type 12 allows linked lists that have entries
in
separately compiled modules to be constructed so that new entries can
be added to one module without editing or
recompiling any other
module.
The data words in a Type 12 block are paired.
The first word of each
pair contains a chain number between 1 and 100 (octal).
(The chain
number is negative if the pair was generated by a .LNKEND pseudo-op.)
The second word contains a store address in the right half, and a
chain address in the left half.
The store address points to the
location where LINK will
place the chain address of the last entry
encountered for the current chain. The first entry in a chain has a
zero in the word pointed to by the store address.
A MACRO statement of the form:
.LINK chain-number,store-address,chain-address
A

MACRO

generates a word pair in a Type 12 block with a a for
the
address field in the REL block.
A MACRO statement of the form:

chain

generates a word pair in a Type 12 block
statement of the form:

shown

above.

.LINK chain-number,store-address

.LNKEND chain-number,store-address
generates a word pair in a Type 12 Block
address and a negative chain number.

with

for

the

chain

As LINK processes a load, it performs a separate chaining
for
each
different chain number found; thus a word pair in a Type 12 block is
related to all other word pairs having the same chain number (even in
other
loaded modules).
Type 12 pairs having different chain numbers
(even in the same module), are not related.

A-21

January 1985

REL BLOCKS
NOTE
Chain numbers
Digital.

above

100

(octal)

are

reserved

To show how the chains are
formed,
we will
take some pairs from
different programs having
the same chain number (1 in the example).
The following four programs contain .LINK or
.LNKEND pseudo-ops for
the chain numbered 1.
After each program, the word pair generated in
the Type 12 block appears.
NOTES

results
from a
When LINK stores an address that
Type 12 REL Block,
only the right half of the
receiving location is written.
You can safely
store another value in the left half; it will not
be overwritten.

Only one fixup by a Type 2, 10, 11, or 12 Block is
allowed for a given field.
(There can be separate
fixups for the left and right halves of the same
word. )

Fixups are not necessarily performed in the
LINK finds them.

A-22

order

January 1985

REL BLOCKS
Example
TITLE MODO

TAGO:

BLOCK 1

.LNKEND 1,TAGO

END

1=======================================================1
-1

1-------------------------------------------------------I
1
0
1
Value of TAGO
1
1=======================================================1

TITLE MODI

TAGI:

BLOCK 1

.LINK I,TAGI

END

1=======================================================1
1

1-------------------------------------------------------I
a
Value of TAGl

1=======================================================1

TITLE MOD2

TAG2:

BLOCK 1

.LINK I,TAG2

END

1=======================================================1
1

\-------------------------------------------------------I
a
Value of TAG2

/=======================================================1

A-23

January 1985

REL BLOCKS

TITLE MOD3

TAG3:

BLOCK 1

TAG33:

BLOCK 1

.LINK I,TAG33,TAG3

END

1=======================================================1
1

1-------------------------------------------------------I

Value of TAG3

Value of TAG33

1=======================================================1

Suppose we
a negative
recognizes
1.
LINK
the chain.

load MODO first. The .LNKEND statement for MODO generates
chain number. LINK sees, the negative chain number (-1) and
this as the result of a .LNKEND statement for chain number
remembers the store address (value of TAGO) as the base of

Next we load MODI. The .LINK statement for MODI does not use the
third argument, so the chain address is O. LINK sees that this is the
first entry for chain number 1. Because it is the first entry, LINK
places a 0 in the store address (value of TAGl). LINK then remembers
the value of TAGI for use in the next chain entry.
(If the chain
address is 0, as it is in MODI, LINK remembers the store address; if
the chain address is nonzero, LINK remembers the chain address.)
Next we load MOD3. The .LINK statement in MOD3 uses a third argument
(TAG3), therefore, the value of TAG3 is used as the chain address.
LINK places its remembered address (value o£ TAGI)
in the store
address
(value of TAG33). Because the chain address (value of TAG3)
is nonzero, LINK remembers it for the next entry.
Finally we load MOD2. Like MODI, the .LINK statement for MOD2 does
not take a third argument, and thus the chain address is O. LINK
places the remembered address (value of TAG3)
in the store address
(value of TAG2). Because the chain address is 0, LINK remembers the
store address (value of TAG2).
At the end of loading, LINK places the last remembered address
(value
of TAG2) at the address (value of TAGO) given by the .LNKEND statement
in MODO.

A-24

January 1985

REL BLOCKS

The results of the chaining can
the loaded core image:

TAGO:

TAG3:
TAG33:

diagram

I
I
TAG2:IValue of TAG3
I
I
I

MOD3

I
I
I
I
IValue of TAGI
I

following

MOD2

MODO

I
I
IValue of TAG2
I
I
I

seen in the

MODI

I
I
TAGI: I
I
I
I

Note that the order of loading for modules with .LINK statements is
critical.
(A module containing a .LNKEND statement can be loaded any
time; its treatment is not affected by the order of loading.)
For example, if we load the four programs in the order
MODO, MODI, we get a different resulting core image:
MODO

TAGO:

I
I
IValue of TAGI
I
I
I

TAG3:
TAG33:

MOD3,

MODI

I
I
TAGI: IValue of TAG3
I
I
I

MOD3

I
I
I
I
IVal ue of TAG2
I

MOD2,

MOD2

I
I
TAG2: I
I
I
I

A-25

January 1985

REL BLOCKS
Block Type 14 (Index)

/=======================================================/
/

177

/-------------------------------------------------------I
Sub~Block
/

. .

/--------------------------~----------------------------I

/-------------------------------------------------------I
/
I
/

Sub-Block

/-------------------------------------------------------I
-1
1 Ptr To Nxt ReI Blk Typ 14 1

/=======================================================/
Each sub-block is of the form:

1===============================;=======================1
/

Index-Version Number

Count of Symbols

/-------------------------------------------------------I
Radix-50 Symbol
/
/-------------------------------------------------------I

/-------------------------------------------------------I
Radix-50 Symbol
/-------------------------------------------------------I
1
Pointer to Module Containing Entry Symbols
1
/

1=======================================================/

Block Type 14 contains a
list of all
entry points
in a
library
produced by MARLIB.
The block contains 177 (octal) data words (with
no relocation words); if the index requires more entries,
additional
Type 14 blocks are used.
If 177 data words are not needed, zero words
pad the block to a length of 177.
-1
indicates the end of the
sub-block information.
The Type 14 block consists of a header word, a number of sub-blocks,
and a trailer word containing the disk block address of the next Type
14 block, if any.
Each disk block is 128 words.
Each sub-block is like a Type 4 block, with three differences:
1.

The sub-block has no relocation words.

The last word of the sub-block points to the module
that
contains the entry points listed in the sub-block.
The right
half of the pointer has the disk block number of the module
within the
file;
the left half has the number of words (in
that block) that precede the module.
If there
is no next
block, then the word after the last sub-block is -1.

The index-version number is used so that old blocks can still
be loaded, even if the format changes in the future.

A-26

January 1985

REL BLOCKS
Block Type 15 (ALGOL)

1=======================================================1
1

Short Count

I------------------~------------------------------------I

Relocation Word

1-------------------------------------------------------I
1
Load Address
1
Length
1
1-------------------------------------------------------I
1
Chain Address
. 1
Offset
1
1-------------------------------------------------------I

1-------------------------------------------------------I
1
Chain Address
1
Offset
1
1=======================================================1

Block Type 15 is used to build the special ALGOL OWN block.
The first data word contains the length of the module's OWN block in
the right half, and the desired load address for the current OWN block
in the left half.
Each following word contains an offset for
the
start of the OWN block
in the
right half, and the address of a
standard righthalf chain of requests for that word of the OWN block in
the left half.
When LINK sees a REL Block Type 15,
it allocates a block of the
requested size at the requested address.
The length of the block is
then placed in the left half of the first word, and the address of the
last OWN block seen is placed in the right half.
If this is the first
OWN block seen, 0 is stored in the right half of the first word.
The remaining data words are then processed by adding the address of
the first word of the OWN block to each offset, and then storing the
resulting value in all the locations chained together,
starting with
the chain address.
At the end of loading, LINK checks to see
if the symbol
%OWN is
undefined.
If
it is undefined, then it is defined to be the address
of the last OWN block seen.
In addition, if LINK is creating an ALGOL
symbol
file,
the file specification of the symbol file is stored in
the first OWN block loaded.
This file specification must be standard
TOPS-I0
format and can include (in order):
device, file name, file
extension, and project-programmer number.

A-27

January 1985

REL BLOCKS
Block Type 16 (Request Load)

1=======================================================1
1
16
1
Short Count
1

1-------------------------------------------------------I
1
Relocation Word (Zero)
1
I----------------------------~--------------------------I
SIXBIT Filename
1

1-------------------------------------------------------I
1
Project-Programmer Number
1
1-------------------------------------------------------I
1
SIXBIT Device
1
1-------------------------------------------------------I
1-------------------------------------------------------I
SIXBIT Filename
1-------------------------------------------------------I
1
Project-Programmer Number
1
1-------------------------------------------------------I
1
SIXBIT Device
1
1

1=======================================================1

Block Type 16 contains a list of files to be loaded. The data words
are arranged in triplets; each triplet contains information for one
file:
file name, project-programmer number, and device.
The file
extension is .REL.
LINK saves the specifications for the files to be loaded, discarding
duplicates.
At the end of loading, LINK loads all specified files
immediately before beginning library searches.
The MACRO pseudo-op .REQUIRE generates a Type 16 REL Block.

A-28

January 1985

REL BLOCKS
Block Type 17 (Request

~ibrary)

1=======================================================1
1
17
1
Short Count
1

1-------------------------------------------------------I
1
Relocation Word (Zero)
1
1-------------------------------------------------------I
SIXBIT Filename
1

I-------------------------------~-----------------------I
1
Project-Programmer Number
1

1-------------------------------------------------------I
SIXBIT Device
1-------------------------------------------------------I
1

I----------------------~--------------------------------I

SIXBIT Filename

Block Type 17 is identical to Block Type 16 except that the specified
files are loaded in library search mode. The specified files are
searched after loading files given in Type 16 blocks, but before
searching system or user libraries.
The MACRO pseudo-op .REQUEST generates a Type 17 REL Block.

A-29

January 1985

REL BLOCKS
Block Type 20 (Common)

1===========================7===========================1
1

Short Count

1-------------------------------------------------------I
1
Relocation Word (Zero)
1
1-------------------------------------------------------I
1
Radix-50 Symbol
1
1-------------------------------------------------------I
Length of Labeled Common Block
1-------------------------------------------------------I
1

1-------------------------------------------------------I
Radix-50 Symbol
1-------------------------------------------------------I
Length of Labeled Common Block
1

1=======================================================1

Block Type 20 allocates labeled COMMON areas.
The label for unlabeled
COMMON is ".COMM.".
If a Block Type 20 appears in a REL file, it must
appear before any other block that causes code to be loaded or storage
to be allocated in the core image.
The data words are arranged in pairs.
The first word of each pair
contains a COMMON name
in Radix-50 format (the four-bit code field
must contain 60).
The second contains the length of the area
to be
allocated.
For each COMMON entry found, LINK first determines whether the COMMON
area
is already allocated.
If not, LINK allocates it.
If the area
has been allocated, the allocated area must be at least as
large as
the current requested allocation.
COMMON blocks can be referenced from other block types as standard
globally defined symbols.
However, a COMMON block must be initially
allocated by a REL Block Type 20, by a REL Block Type 6
(for blank
COMMON),
or by the /COMMON switch to LINK.
Any attempt to initially
define a COMMON block with a standard global symbol definition causes
the LNKSNC error when the redefining Block Type 20 is later seen.

A-30

January 1985

REL BLOCKS
Block Type 21 "(Sparse Data)

I======================z====.===========================1
1
21
1.
Short Count
1
I----------------------~--------------------------------I

Relocation Word

(Zero)

I--------------------~----------------------------------I

1
1

Sub-Block

1-------------------------------------------------------I

1-------------------------------------------------------I
1
1

Sub-Block

1=======================================================1
Each sub-block is of the form:

1=======================================================1
Long Count
1
Address
1
1-------------------------------------------------------I
1
Data Word
1
1-------------------------------------------------------I
1

1-------------------------------------------------------I
1
Data Word
1
1=======================================================1
Block Type 21 contains data to be loaded sparsely in a
large area.
The
first
word of each sub-block contains the long count for the
sub-block in the left half, and the address for loading the data words
in the right half.
If the first four bits of the first data word of each sub-block are
1100 (binary) then the word is assumed to be a Radix-50 symbol of type
60; in this case the left half of the second word
is the
sub-block
count,
and
the
right half plus the value of the symbol is the load
address.

A-31

January 1985

REL BLOCKS
Block Type 22 (PSECT Origin)

1=======================================================1
1

Short Count

1-------------------------------------------------------I
Relocation Word
1-------------------------------------------------------I
(SIXBIT PSECT Name) or (PSECT Index)
1-------------------------------------------------------I
PSECT Origin
1

1=======================================================1

Block Type 22 contains the PSECT origin (base address).
Block Type 22 tells LINK to set the value of the relocation counter to
the value of the counter associated with the given PSECT name. All
following REL blocks are relocated with respect to this
PSECT until
the next Block Type 22 or 23 is found.
When data or code is being loaded into
this PSECT,
addresses are relocated for the PSECT counter.

all

relocatable

MACRO generates a Block Type 22 for each .PSECT and
.ENDPS
it processes.
These Type 22 blocks are interleaved with
blocks to indicate PSECT changes.
A Type 22 block is also
at the beginning of each symbol table to show to which PSECT
refers.

A-32

pseudo-op
the other
generated
the table

January 1985

REL BLOCKS
Block Type 23 (PSECT End Block)

1=======================================================1
1
23
1
Short Count
1
I-----------------------------~-------------------------I

PSECT Index

1-------------------------------------------------------I
PSECT Break
1

1=======================================================1

Block Type 23 contains information about a PSECT.
The PSECT index uniquely identifies the PSECT within the module
loaded.
The Type 24 block assigns the index.

being

The PSECT break gives the length of the PSECT.
This break is relative
to the zero address of the current module, not to the PSECT origin.

A-33

January 1985

REL BLOCKS
Block Type 24

(PSECT Header Block)

1=======================================================1

Short Count

1-------------------------------------------------------I
Relocation Word
1-------------------------------------------------------I
PSECT Name (SIXBIT)
1-------------------------------------------------------I
Attributes
PSECT Index
1-------------------------------------------------------I
PSECT Origin
1

1=======================================================1

Block Type 24 contains information concerning a specified PSECT.
The
first word contains
the block type number and the number of words
associated with the block.
The second word contains
the
relocation
information.
The
third word contains the PSECT name in SIXBIT.
The
fourth word is the PSECT origin specified for this module.
Bit

Interpretation

MACRO .PSECT Keyword

PSECT is page-aligned.

PALIGNED

Concatenate parts of
PSECTs seen in distinct modules.

CONCATENATE

Overlay parts of PSECTs
seen in distinct modules.

OVERLAY

Read-only

RONLY

Read and write

RWRITE

LINK must find a Type 24 block for a PSECT before it finds
the
index
for that PSECT.
{MACRO generates a complete set of Type 24 blocks for
all PSECTS in a module before generating Type 2 (Symbol Table)
Blocks
and Type 11 (POLISH) Blocks.)

A-34

January 1985

REL BLOCKS
Block Type 37 (COBOL Symbols)

1=======================================================1
1
37
1
Short Count
1

1-------------------------------------------------------I
Relocation Word
1-------------------------------------------------------I
Data Word
1-------------------------------------------------------I
1

1-------------------------------------------------------I
Data Word
1

1=======================================================1

Block Type 37 contains a debugging symbol table for COBDDT, the COBOL
debugging program.
If local symbols are being loaded, the table is
loaded.
If a REL file contains a Block Type 37, it must appear after all other
blocks that cause code to be loaded or storage to be allocated in the
core image.
This block is in the same format as the Type 1 REL Block.

A-35

January 1985

REL BLOCKS
Block Type 100 (.ASSIGN)

1=======================================================1
100

Short Count

1-------------------------------------------------------I
1
Relocation Word
1
I-------------------------~-----------------------------I
Radix-50 Symbol I
1

ICode 1

I---------------------------------------------------~---I

ICode

Radix-50 Symbol 2

1-------------------------------------------------------I
Offset
1

1=======================================================1

Block Type 100 defines Symbol 1 (in the diagram above) as a new global
symbol with the current value of Symbol 2, and then increases the
value of Symbol 2 by the value of the given offset.
NOTE
Symbol 2 must be completely
Type 100 is found.

A-36

defined

when

the

Block

January 1985

REL BLOCKS
Block Type 776 (Symbol File)

1=======================================================1
1

776

Long Count

1-------------------------------------------------------I
.JBSYM-Style Symbol Table Pointer
1-------------------------------------------------------I
.JBUSY-Style Symbol Table Pointer
1-------------------------------------------------------I
Data Word
1

I-----------------------~-------------------------------I

1-------------------------------------------------------I
Data Word
1

1=======================================================1

Block Type 776 must begin in the first word of the file, if it occurs
at all.
This block type shows that the file is a Radix-50 symbol
file.
The data words form a Radix-50 symbol table for DDT in the same format
as the table loaded
for
the switches /LOCALS/SYMSEG or the switch
/DEBUG.

A-37

January 1985

REL BLOCKS
Block Type 777 (Universal File)

1=======================================================1
1

777

Long Count

1-------------------------------------------------------I
Data Word
1

I-----------------------~-------------------------------I

1-------------------------------------------------------I
Data Word
1

1=======================================================1

Block Type 777 is included in a universal (UNV) file that is produced
by MACRO so that LINK will recognize when a UNV file is being loaded
inadvertently.
When a Block Type 777 is encountered, LINK produces a
?LNKUNS error.

A-38

January 1985

REL BLOCKS

Block Type 1000 (Ignored)

1=======================================================1
1
1000
I·
Long Count
1

1----------------------------------------------------- --I
1

Data Word

I-------------------~-----------------------------------I

1----------------------------------------------------- --I
1

Data Word

1=======================================================1

Block Type 1000 is ignored by LINK.

A-39

January 1985

REt. BLOCKS
Block Type 1001 (Entry)

1=======================================================1
1
1001
1
Long Count
1

1-------------------------------------------------------I
Symbol
1

I--------------------------~----------------------------I

1-------------------------------------------------------I
Symbol
1

1=======================================================1

Block type 1001 is used to declare symbolic entry points.
Each word
contains one SIXBIT symbol.
This block is similar in function to
block type 4.

A-40

January 1985

REL BLOCKS
Block Type 1002 (Long Entry)

1===============3:==:==============~====================1

1
1002
1
Long Count
1
1---------------------··---------------------------------I
Symbol Name
1
I-------------------------------~-----------------------I

1-------------------------------------------------------I
Symbol Name
1

I=======:===============================~===============1

Block Type 1002 is used to declare a s'ymbolic entry point with a
name in SIXBIT. The count reflects the symbol length in words.

LINK V6.0

A-40.l

long

April 1986

REL BLOCKS
Block Type

1~~3

(Long Title)

======:==:===========~===============~=================

1
1~~3
1 .'. Long Count
1
1-----------------------------------------------------1
1
1
1 Count of Title words 1
1--------------_·_-------------------------------------I
1
Program Title
1
1-----------------------------------------------------1
1
Additional Program Title
1
1-----------------------------------------------------1
1
Additional Program Title
1
1-----------------------------------------------------1

11-----------------------------------------------------1
1
Count of
1
1
2
1 ASCII Comment Words
1
1-----------------------------------------------------1
1
More Comment Words
1
11-----------------------------7-----------------------1
More Comment Words
1
I-----------------------------~-~---------------------1

11-----------------------------------------------------1
3
1 Count of Compiler Words 1
1-----------------------------------------------------1
1
Compiler Code
1
CPU Bits
1
1-----------------------------------------------------1
1
Compiler Name (in ASCII)
1
1----------------_·_-----------------------------------I
1
Additional Compiler Name
1
1-----------------------------------------------------1
1
Additional Compiler Name
1
1-----------------------------------------------------1
1----------------------------------------------------1
1
4
1
0
1
1----------------------------------------------------1
1
Compile Date and Time
1
1----------------------------------------------------1
1
Compiler Version Number
1
1----------------------------------------------------1

LINK V6.0

A-40.2

April 1986

REL BLOCKS
Block Type

1~~3

(Cont.)

================~=======:====================~======

5
Device Name
SIXBIT UFD
6
TOPS-l~

File Name

File Extension

Number of SFDs
SIXBIT SFD 1
SIXBIT SFD 2

11----------------------------------------------------1
1 Count of
File
1
1
1 Spec Words (in ASCII) 1
1----------------------------------------------------1
1
File Spec
I
1----------------------------------------------------1
1
File Spec
1
1----------------------------------------------------1
1~

TOPS-1~

TOPS-l~

1-----------------------------------------------------1
1
11
1
~
1
1----------------------------------------------------1
1
Source Version Number
1

1----------------------------------------------------1
1
Date and Time
1
I=================~~====================~============I

Block Type 1~03 is used to declare long title symbols in SIXBIT and to
furnish other information about the source module. This block type
contains the information that LINK prints in the map file.
Block Type l~03 consists of sub-blocks 1 through 11
(octal).
The
Title sub-block must be the first sub-block specified and cannot be
omitted. You can omit other sub-blocks, but the sub-blocks must
remain in numerical order.
The Program Title is a one word title from 1 to 72 SIXBIT characters
long.
You can specify a title of 0, and LINK defaults to .MAIN, but
you may want to enter a more specific title.
For the compiler code and the CPU code, refer to
Block Type 6, where these codes are listed.

LINK V6.0

A-4~.3

the

explanation

April 1986

REL BLOCKS
Sub-blocks 5 through 7 contain the device name, UFD, and SFD where the
file resides.
In sub-block 10, the TOPS-10 file specification must be
the following format:

specified

[dir]file.ext
This specification identifies the source file.
LINK outputs this file
specification to the map file in ~he order you enter it.
The Time and Date are in TOPS-10 format. The date is derived
code that is given by the following formula:
code =

from

31[12(year-1964)+(month-l)]+(day-l)

You can obtain the current day, month, and year using the formulas:
day = mod(code,31)+1
month = mod(code/31,12)+1
year = (code/372)+1964
The Time is the time in milliseconds that has elapsed since midnight.
See the TOPS-10 Monitor Calls Manual
specifying date and time.

LINK V6.0

A-40.4

for

additional

information

April 1986

REL BLOCKS
Block Type lBB4 (Byte Initialization)

1I=======~==============================================1
10B4
1
Long Count
1
1------------------------------------------------------I
1
Relocation Word
1
1-------------------------------------------------------I
1
Byte Count
1
1------------------------------------------------------I
1
Byte Pointer
1
1------------------------------------------------------I
1
Byte String
1
1------------------------------------------------------I

The above Block Type lBB4 format is used to move a character
into static storage. This format uses old style relocation.

string

The byte count is the number of bytes in the string. The byte pointer
is relocated and used to initialize a string in the user's program.
A second format for Block Type l0B4 follows:
===========:==============================:============

10B4

Long

Count

Relocation Word
Global Symbol
Byte Count
Byte Pointer
Byte String

In this format, the global symbol (in SIXBIT) is used to relocate the
byte pointer.
The symbol must be defined when this REL block is
encountered.

LINK V6.B

A-4B.5

April 1986

REL BLOCKS
Block Types 1m1m - 1m37 (Code Blocks)

Block Types 1010 through 1037 are similar in function to Block Type 1.
They contain code and data to be loaded. These blocks also contain
relocation bytes that permit inclusion of PSECT indexes local to the
module.
For
programs
that use PSECTs with many inter-PSECT
references, this permits a substantial decrease in the size of the REL
files.
The number of PSECTs that can be encoded in this manner is
limited by the size of the relocation byte. A set of parallel code
blocks differing only in the size of the relocation byte permits the
compiler or assembler
to
select
the
most
space
efficient
representation according to the number of PSECTs referenced in a given
load module.
This set of blocks is divided by the type of relocation:
Right Relocation

Block Types 1010 - 1017

Left/Right Relocation

Block Types 1020 - 1027

Thirty-bit Relocation

Block Types 1030 - 1037

LINK V6.0

A-40.6

April

~986

REL BLOCKS
Block Type 1042 (Request Load for SFDs)

/=======================================================1
1042

Long Count

-------------------------------------------------------I
Device
/
-------------------------------------------------------/
SIXBIT Filename
-------------------------------------------------------I
File Extension
Directory Count
-------------------------------------------------------/
Project-Programmer Number
/
-------------------------------------------------------I
SFDl
-------------------------------------------------------I
SFD2
-------------------------------------------------------I
1

Block Type 1042 contains a list of files to be loaded. It is similar
to blocks of Type 16, but it supplies TOPS-10 sub-file directories for
the files being requested. The first three data words (device, file
name, and extension) are required. The right half of the third word
(directory count) specifies the number of directory levels that are
included. For example, the directory [27,5434,SFD1,SFD2] would have a
directory count of 3.
LINK saves the specifications for the files to be loaded, discarding
duplicates. LINK loads all specified files at the end of loading, and
immediately before beginning library searches.

A-41

January 1985

REL BLOCKS
Block Type 1043 (Request Library for SFDs)

=======================================================1
1043

Long Count

Device
SIXBIT Filename
File Extension

Directory Count

Project-Programmer Number
SFDI
SFD2

Block Type 1043 specifies the files to be searched as libraries.
It
is similar to Type 17 Blocks, except that it provides TOPS-I0 sub-file
directories. The first three data words
(device, file name, and
extension)
are required. The right half of the third word (directory
count) specifies the number of directory levels that are included.
For example, the directory [27,5434,SFDl,SFD2] would have a directory
count of 3.
The specified files are searched after requested files are loaded, but
before user and system libraries are searched.

A-42

January 1985

REL BLOCKS
Block Type

104·~

(ALGOL Symbols)

1=======================================================1
1
1044
1
Long Count
1

1-------------------------------------------------------I
Data Word
1

I-----------------------------~-------------------------I

1-------------------------------------------------------I
Data Word
1

1=======================================================1

Block Type 1044 contains a debugging
ALGOL debugging program.

symbol

table

for

ALGDDT,

the

If an ALGOL main program has been loaded, or
if you have
used
the
/SYFILE:ALGOL switch, LINK writes the data words into a SYM file.
In
addition, if any Type 15 (ALGOL OWN) REL blocks have been seen,
LINK
stores the
file
specification of the file into the first OWN block
loaded.
NOTE
If you have specified the /NOSYMBOLS switch, or if you
have specified the /SYFILE switch with an argument
other than ALGOL, then LINK
ignores any Type 1044
blocks found.

A-43

January 1985

REL BLOCKS
Block Type 1045 (Writable Links)

1=======================================================/
1

1045

Long Count

1-------------------------------------------------------I
Flags
/
1-------------------------------------------------------I
Symbol
/
1-------------------------------------------------------I
Symbol
/
1-------------------------------------------------------I
1
1

1-------------------------------------------------------I
Symbol
/
1

/=======================================================/

Block type 1045 declares as writable either the link containing the
current module or the links containing the definitions of the
specified symbols or both. This block type must follow any common
block declarations (Types 20 or 6) in a module.
The flag word indicates which links are writable. If bit one is set
then the link containing the current module and the links containing
the definitions of the specified symbols are writable. If bit one of
the flag word is not set then the link containing the current module
is not writable, but the links containing the specified symbols are
writable. All unused flag bits are reserved and should be zero.
Any symbols specified in a block of Type 1045 must be defined in the
path of links leading from the root link to the current link. A
module cannot declare a parallel or inferior link to be writable.
If the symbol name contains six or fewer characters it is represented
in a single word, left justified, with the following format:

/=======================================================/
SIXBIT Symbol Name
/
1=======================================================/
1

A-44

January 1985

REL BLOCKS
If the symbol name contains more than six characters it is represented
in the following format:
Bits

o
5 6
29
30
35
/=======================================================/
/

Reserved (0)

Long Count

/-------------------------------------------------------I
/
Word 1 of SIXBIT Symbol Name
/
/-------------------------------------------------------I
/
Word 2 of SIXBIT Symbol Name
1
/-------------------------------------------------------I

1-------------------------------------------------------I
/

Word (N-l) of SIXBIT Symbol Name

/=======================================================/

The first six bits of a long symbol are always O. This distinguishes
a long symbol name from a single word symbol name. N is the length of
the symbol name including the header word.
The remaining words
contain the symbol name
in SIXBIT, six characters to a word, left
justified.

A-45

January 1985

REL BLOCKS
Block Type 1059 (Long PSECT Name Block)

o
17 18
35
I====================:=====~:===========================1
1
1050
1
Long Count
1
1-------------------------------------------------------I
1 Reserved for DIGITAL, MBZ 1
Index
1
1-------------------------------------------------------I
I
SIXBIT Symbol Name
1
1-------------------------------------------------------I
1
Attributes
1
1--------------------------------------------------------I
1
Origin
(Optional)
1
1==============================================:=========1
where SIXBIT Symbol Name may be either a word
characters, or the following block.

5 6

six

29 30

SIXBIT

I===============================================~=======1

1
0
1 Reserved for DIGITAL, MBZ 1 Long Count
1
1-------------------------------------------------------I
1
First word of SIXBIT Symbol Name
1
1-------------------------------------------------------I
1
Second word of SIXBIT Symbol Name
1
1-------------------------------------------------------I

1-------------------------------------------------------I
1
Nth word of SIXBIT Symbol Name
1
1=======================================================1
Block Type 1059 creates a PSECT with the given name, if none currently
exists.
It also assigns a unique index number to the PSECT. This
index is binding only in the current module.
LINK clears PSECT
indexes at the end of each module.
PSECT indexes in any given module
must be declared in consecutive order starting at index 1.
Block Type 1050 also assigns attributes to a PSECT and specifies
PSECT's origin address.
The attributes that can be assigned are:

the

Bit

Description

PSECT is confined to one section.
If this bit is set,
LINK gives an error if the PSECT overflows.
You can
set Bit 11 or Bit 12, but not both.
Bit 11
is the
default.
There is no equivalent MACRO .PSECT keyword.

PSECT is in a nonzero section.
If this bit is set,
LINK gives a warning if the PSECT is placed in Section
0.
There is no equivalent MACRO .PSECT keyword.

PSECT is PAGE-ALIGNED.
MACRO .PSECT keyword.

LINK V6.0

A-46

PALIGNED

the

equivalent

April 1986

REL BLOCKS
Bit

Description

CONCATENATED parts of PSECTs seen in distinct modules.
You can set Bit 14 (CONCATENATED) or Bit 15 (OVERLAID),
but not both.
The CONCATENATE and OVERLAID attributes
are mutually exclusive. These attributes span modules;
so
if one module sets an attribute and a later module
sets a mutually exclusive attribute,
LINK issues the
warning:
%LNKCOE Both CONCATENATE
specified for psect [name].

and

OVERLAY

attributes

If neither is set, CONCATENATED is the default,
and a
warning message is not returned if subsequent pieces of
the PSECT are marked OVERLAID.
CONCATENATED is the equivalent MACRO .PSECT keyword.

OVERLAID parts of PSECTs seen in distinct modules.
OVERLAID is the equivalent MACRO .PSECT keyword.

This PSECT must be READ-ONLY.
You can set Bit 16 (READ-ONLY) or Bit 17
(WRITABLE),
but not both.
The READ-ONLY and WRITABLE attributes
are mutually exclusive. These attributes span modules;
so if one module sets an attribute and a later module
sets a mutually exclusive attribute,
LINK issues the
warning:
%LNKRWA Both
READ-ONLY
and
specified for psect [name].

WRITABLE

attributes

If neither is set, WRITABLE is the default, and a
warning message is not returned if subsequent pieces of
the PSECT are marked READ-ONLY.
RONLY is the equivalent MACRO .PSECT keyword.
17

This PSECT must be WRITABLE.
MACRO .PSECT keyword.

RWRITE is the

equivalent

All other bits in the Attributes word must be 0.
The origin specified in this block is absolute.
At least one Block Type 1050
(or the related Block Type 24)
is
required for each PSECT being loaded, and this block must be loaded
prior to any other blocks that reference its PSECT (that is,
use the
unique index number).

LINK V6.0

A-47

April 1986

REL BLOCKS
Block Type 1051 (Set Current PSECT)

I=======================:=:=====:~:=====================1

1
1051
1
Long Count
1
1-------------------------------------------------------I
1 Reserved for DIGITAL, MBZ 1
Index
1
1===========================:===========================1
Block Type 1051 resets the "current PSECT", against which LINK
relocates subsequent REL blocks if no PSECT is explicitly specified.

LINK V6.0

A-48

April 1986

REL BLOCKS
Block Type 1052 (PSECT End)

I=========~=====================::==:===================1

1
1052
1
Long Count
1
1-------------------------------------------------------I
1
MBZ
1 PSECT Index Number
1
1-------------------------------------------------------I
1
PSECT Break
1
1-------------------------------------------------------I

1-------------------------------------------------------I
1
MBZ
1 PSECT Index Number
1
1-------------------------------------------------------I
1
PSECT Break
1
1=======================================================1
Block Type 1052 allocates additional space for a given PSECT.
This
space is located between the last address in the PSECT containing data
and the address given by the PSECT break. A block of Type 1052 can
contain more than one pair of PSECT indexes and breaks.
A module must contain a block of Type 24 (PSECT Name)
or Type 1050
(Long PSECT Name)
with the given PSECT index before a block of Type
1052 is generated.
If a given PSECT has more than one Block Type 1052
in a single module, the block with the largest break address is used.
The break is interpreted as being relative to the
the current module.

LINK V6.0

A-49

PSECT's

origin

April 1986

REL BLOCKS
Block Type

1~6~

(Trace Block Data)

=======================================================1
106~

Long Count

-------------------------------------------------------I
SIXBIT Edit Name
1
Active Code

Last Changer

Creator Code

15-Bit Date Created

Installer Code

15-Bit Date Installed
Reserved

Edit Count

PCO Group Count

Associated Edit Names and Codes

1-------------------------------------------------------I
1

/
Program Change Order Groups

I===============================~=======================1

Block Type 1~6~ contains
ignores this block type.

data

used

A-5~

the

MAKLIB

program.

LINK

April 1986

REL BLOCKS
Block Type 1979 (Long Symbol Names)

I=====:=~:===================~======:================================1

1
1070
1
Long Count
1
I-----------------------------------~--------------------------------1
1
Code
10 1
N
Ipi R 1
V
1
0
1
1--------------------------------------------------------------------1
1
Left PSECT index
1
Right PSECT index
1
1--------------------------------------------------------------------1
1
Value
1
1--------------------------------------------------------------------1
1
Name
1
1--------------------------------------------------------------------1

n Additional Name Words

I------------------------------~-------------------------------------1

v Additional Value Words

I=====~=~============================================================1

This block defines a long symbol.
can:

A symbol defined

with

this

block

be written to the DDT symbol table. Symbols longer than 6
characters are truncated when output to the DDT symbol table.

be written to the map file if requested.

have its value relocated as specified.

resolve global requests.

The Long Symbol Name Block is divided into two sections, the basic and
the extension sections.
The basic section consists of four words: the flag word, an
PSECT index word, the value word, and name word.

optional

The Flag word contains information about the type of symbol, the
length of the symbol name, and relocation. The optional word defines
the PSECT index. The Value word contains the symbol's value.
The
Name word contains the symbol's name.
If the name or the value cannot fit in a single word, the block
contains an extension section that consists of as many words as are
necessary to accommodate the symbol name and the value. The length of
the symbol name and value is stored in the Flag word and determines
how many words are allocated for the long symbol name in the extension
section.
The maximum size of the symbol is 72 characters. In the
case of a short symbol name, only the basic section is used.
The following pages provide detailed information on the
each word, the field, bits, and description is given.

LINK V6.0

A-51

block.

For

April 1986

REL BLOCKS
Header Word
Field

Bits

Description

Block Type

0-17

1070

Block Length

18-35

Number of words used in this block
Flag Word

Field

Bits

Code

0-8

Description
A nine-bit code field:
Bit 0

Must Be Zero

000

Program name

100

Local symbol definitions
110 Suppressed to DDT
120 MAP only

200

Global
symbols
complately
defined by one word
202 Undefined
203 Right fixup
204 Left fixup
205 Right and left fixups
206 30-bit fixup
207 Fullword fixup
210-217 Suppress to DDT
220-227 MAP only
Global symbol request for
chain fixup
240 Ignored (no fixup)
241 Undefined
242 Undefined
243 RH fixup
244 LH fixup
245 Undefined
246 30-bit fixup
247 Fullword fixup
Global request for additive
fixups (the value of x has the
same meaning as in 0-7 above)

240247

250257
260267

Global request for additive
symbol fixups (the value of x
has the same meaning as in 0-7
above)

300

Block names

NOTE
All symbols that require a fixup for their definition
must have the fixup block immediately following the
entry.

LINK V6.0

A-52

April 1986

REL BLOCKS
Field

Bits

Description

9-10

Must Be Zero

N--Name length

11-17

If not zero, extended name field of
length n words is used, so that the
name occupies n+l words.

P--PSECT Flag

If Bit 18=0, relocate with respect to
the current PSECT.
No PSECT numbers
are needed.
If Bit 18=1, relocate with respect to
the PSECT specified in the next word.

R--Relocation Type

19-21

3-bit relocation type field.

o
1
2
3
4
5
V--Value field

Absolute
Right half
Left half
Both halves
30-bit
Fullword

22-28

Number of additional value
value is a long symbol.

29-35

Not used

words

PSECT Indexes
PSECT Indexes

Exists only if Bit 18 equals 1 in the
Flag word.
Contains Left and Right
PSECT numbers. Bit 0 and Bit 18 of
this word are zeros.
Value

Value Word

Contains the symbol value. This may
be relocated as specified by the
relocation type and the PSECT numbers
provided.
Contains a symbol for 26x
codes.
Name

Name Word

Contains the symbol name in SIXBIT.
N Additional Name Words

Additional name field

Optional. It exists only if N > 0.
It contains the additional characters
when a long symbol name is used.
V Additional Value Words

Additional value field

Optional. It exist only if the V
field
is greater than 0. This field
contains the additional characters
when a long symbol name is being
resolved. The first word contains
the length of the extended field.

LINK V6.0

A-53

April 1986

REL BLOCKS

The following fixup rules apply to this block:
•

Only one fixup by a Type 2, 10, 11, 12, 15, 1070, 1072, or
1120 Block is allowed for a given field. There can be
separate fixups for the left and right halves of the same
word.

•

Fixups are not necessarily performed in the order LINK
them.

•

Chained halfword fixups cannot cross section boundaries; they
wrap around to the beginning of the section. Also, they
cannot fixup a location that resolves to word zero of a
section unless it is the only address in the chain.

•

Chairted fixups must be in strict descending address order.

•

A location must contain data before the location can be fixed
up.

LINK V6.0

A-54

finds

April 1986

REL BUOCKS
Block Type Ig72 (Long Polish Block)
1===~========~===================~=========3============1

1072

Long

Count

1------------------------,-------------------------------I
1
Half-Word Polish String
1
1-------------------------------·-----------------------I

1=======================================================1
Long Polish Blocks of Type 1072 define Polish fixups for operations on
relocatable long external symbols. This Block Type is interpreted as
a string of l8-bit operators and operands. The block is in Polish
prefix format, with the store operator at the end of the block. Each
halfword can contain one of the following:
•

A halfword code in which the first 9 bits contain the data
length (when applicable) and the second 9 bits contain the
code telling LINK how to interpret the data that follows.

•

A halfword data or a part of a larger data packet to be
interpreted by LINK as indicated by the code that immediately
precedes it.

•

A PSECT index of the format 400000+n. The PSECT index field
of a long Polish block causes LINK to relocate addresses
against the PSECT number specified in the Un" of the PSECT
index 400000+n.

•

A Polish operator.
NOTE
Operations are performed in the order
are encountered.

which

they

CODE DEFINITIONS
Data Packet Codes
Category

Code

Operand

xxxyyy

next "xxx+l" halfwords contain data of
type "yyy"

000000
001000

halfword - absolute
fullword - absolute

000001
001001

halfword - relocatable
fullword - relocatable

Description

fullword symbol name in Radix-50
xxx+l halfwords of symbol name
SIXBIT

NOTE
You cannot store a symbol in a single halfword.
You
must place the symbol in the first halfword and fill
the second halfword with zeroes.
LINK V6.0

A-55

April 1986

REL BLOCKS
Polish Operator Codes
Category

Code

Description

Operator
000100
000101
000102
000103
000104
000105
000106
000107
000110
000111
000112
000113
000114
000115
000116
000117
000120
000121
000122-00177

Add
Subtract
Multiply
Divide
Logical AND
Logical OR
Logical shift
Logical XOR
One's complement (not)
Two's complement (negative)
Count leading zeros
Remainder
Magnitude
Maximum
Minimum
Equal relation
Link
Defined
Reserved

Store Operator Codes
Store Operator

LINK V6.0

xxx=0 or 1
For xxx=0

Next two halfwords contain a
symbol to be resolved.

xxx777-xxx770

Chained
fixup
with
relocatable
addresses.
Next
xxx+1
halfwords
contain the start address of
the
chain.

000777

Right
half
chained
fixup
with
relocatable address.
Next halfword
contains a relocatable address.

000776

Left
half
chained
fixup
with
relocatable address.
Next halfword
contains a relocatable address.

000775

30-bit chained fixup with
address.
Next halfword
relocatable address.

000774

Fullword
chained
fixup
with
relocatable address.
Next halfword
contains a relocatable address.

001777

Right
half
chained
fixup
with
relocatable address.
Next fullword
contains a relocatable address.

001776

Left
half
chained
fixup
with
relocatable address.
Next fullword
contains a relocatable address.

A-56

Radix-50

relocatable
contains a

April 1986

REL BLOCKS

PSECT index

1211211775

3121-bit chained fixup with
address.
Next fullword
relocatable address.

relocatable
contains a

1211211774

Fullword
chained
fixup
with
relocatable address.
Next halfword
contains a relocatable address.

xxx767-xxx764

Chained
fixups
addresses.

121121121767-121121121764

Chained fixup with absolute
Next halfword contains an
address.

1211211767-1211211764

Chained fixup with absolute fullword
address.
Next two halfwords contain
absolute address.

xxx757-xxx754

Symbol fixup.
For 1<=xxx<=377 the
next xxx+l halfwords contain a SIXBIT
symbol name to be resolved.

xxx757
xxx756
xxx755
xxx754

Right half symbol fixup.
Left half symbol fixup.
3121-bit symbol fixup.
Ful1word symbol fixup.

xxx747-xxx7121121

Not defined

4 121121 121121 121 l2I+n

PSECT index for PSECT N.

with

absolute
address.
absolute

The following fixup rules apply to this block:
•

Only one fixup by a Type 2, 1121, 11, 12, 15, 11217121, 112172, or
112121 Block is allowed for a given field. There can be
separate fixups for the left and right halves of the same
word.

•

Fixups are not necessarily performed in the order LINK
them.

•

Chained halfword fixups cannot cross section boundaries; they
wrap within a section. Also, they cannot fixup a location
that resolves to word zero of a section unless it is the only
address in the chain.

•

Chained fixups must be in strict descending address order.

•

A location must contain data before the location can be fixed
up.

LINK V6.121

A-57

finds

April 1986

REL BLOCKS
Block Type

l~74

(Long Common Name)

1=======================================================1
1
1~74
1
Long Count
1
1-------------------------------------------------------I
1
PSECT Index
1
Symbol Length
1

1-------------------------------------------------------I
1
Common Block Length
1
1-------------------------------------------------------I
Symbol
1

(More Symbol)

===================================================~== ====

Block Type

LINK V6.m

1~74

defines a long COMMON name.

A-58

April 1986

REL BLOCKS
Block types 1129-1127

(Argument Descriptor Blocks)

I=====:====================~=~===:======================
1
1120 - 1127
1
Long Count

1------------------------------------------------------N-Bit Byte Relocation Information
Argument Block Address

or 0

Associated Call Address or 0
Loading Address or 0
Length of Function Name (in bytes)
Function Name (ASCIZ)

1-------------------------------------------------------I
1
Flag Bi ts
1
Argument Count
1
1-------------------------------------------------------I
1
First Argument's Primary Descriptor
1
1-------------------------------------------------------I
1
First Argument's Secondary Descriptor
1
1-------------------------------------------------------I
1
Second Argument's Primary Descriptor
1
1-------------------------------------------------------I
1
Second Argument's Secondary Descriptor
1
1-------------------------------------------------------I

1-------------------------------------------------------I
1
nth Argument's Primary Descriptor
1
1-------------------------------------------------------I
1
nth Argument's Secondary Descriptor
1
1=======================================================1
A block of this type is generated for the argument list to each
subroutine call. The subroutine entry point also specifies one block
with this format, though for the cal lee the argument block address is
zero.
If a descriptor block is associated with an argument list it
must always follow the loading of the argument list.
The associated call address is used by LINK in diagnostic error
messages and its value is determined by the compiler. The argument
block address is nonzero if the descriptor block is associated with a
call.
In this case the argument block address points to the base of
the argument block.
The argument block address, associated call address
address are all relocatable.

and

the

The argument descriptors in these type blocks describe the properties
of each formal (in the case of an entry point) or actual (in the case
of a call). In either case the name of the associated routine is
specified as a byte count, that can only be 6 characters long,
followed by an ASCIZ string. Each primary description is optionally
followed by a secondary descriptor.
A-59

April 1986

REL BLOCKS
There are five flag bits in the Descriptor Block:
Bit

Usage
If bit 0 is 1 then a difference between the actual
number of arguments and the expected number of
arguments is flagged as a warning at load time.
If
bit 0 is 0 no action is taken.

If bit 1 is 1 then the block is associated with a
function call.
If bit 1 is 0 then the block is
associated with the function definition.

If bit 2 is 1 then the descriptor block is loaded
into user memory at the loading address. This bit
is ignored.

If bit 3 is 1 then the cal lee returns a
the
value's descriptor is the last
specified.

If bit 4 is 1, and the caller expects a return
value, which is not provided by the called function,
or if the called function unexpectedly returns a
value, then LINK will issue an error. The severity
of the error is controlled by the coercion block.

value and
descriptor

The format for the argument descriptors is as follows:
Bit

Usage

(Reserved)

No update. In a caller block the argument is a
literal, constant, or expression. In a cal lee block
the argument won't be modified.

2-4

Passing mechanism
000 - pass by address
001 - pass by descriptor
010 - pass immediate value
Others - reserved

Compile-time constant

6-11

Argument type code (see below)

12-17

(Reserved)

Implicit argument descriptor

19-26

(Reserved)

27-35

Number of secondary descriptors

A-60

April 1986

REL BLOCKS
The argument type codes are as follows:
Type-Code

Usage

FORTRAN logical

Integer

(Reserved)

Real

(Reserved)

36-bit string

Alternate return (label)

Double real

Double integer

Double octal

G-floating real

Complex

COBOL format byte str ing descr iptor,
strings), or FORTRAN character

BASIC shared string descriptor

ASCIZ string

Seven-bit ASCII string

(for

constant

Secondary descriptors are used to convey information about the length
of a data object passed as an argument and (in the case of the
callee's argument descriptor block) whether or not a mismatched length
is permissible. Secondary descriptors have the following format:
Bit

Usage

POSe

0-2

(For callee only) Defines the permissible relationships
between formal and actual lengths. The values are:
000 001 010 011 100 101 110 -

Any relationships are allowed
Lengths must be equal
Actual < formal
Actual <= formal
Actual > formal
Actual >= formal
Reserved
I I I - Reserved

3-5

Length of argument (in words)

A-61

April 1986

REL BLOCKS
Block Type

ll3~

(Coercion Block)

I==========================================~============1
I
1130
1
Long Count
1

1-------------------------------------------------------I
Field Code
I
Action
1
1-------------------------------------------------------I
i
Formal Attribute
1
Actual Attribute
1
1-------------------------------------------------------I
!
Field Code
1
Action
1
\-------------------------------------------------------I
I
Formal Attribute
1
Actual Attribute
1
1-------------------------------------------------------I
~

1-------------------------------------------------------I
1
Field Code
1
Action
1
1-------------------------------------------------------I
I
Formal Attribute
1
Actual Attribute
1
1=======================================================1

Block Type 113~ specifies which data type associations are permissible
and what action LINK should take if an illegal type association is
attempted. It may also specify actions to be taken by LINK to modify
an actual parameter.
The Coercion Block must be placed before any instance of the
caller/callee descriptor block in the REL file. If more than one
coercion block is seen during a load, the last block seen is used for
type checking.
If the descriptor block and command
section, no error message is given.

strings

are

not

the

same

When a caller's argument descriptor block is compared to
the
descriptor block provided by the callee, LINK first checks bit ~ and
the argument counts of the descriptor block. If bit 0 is set and the
argument counts differ, a warnlng is given.
However, if a byte
descriptor is not word-aligned, no warning is given.
Next LINK compares the argument
descriptors.
The
particular
formal/actual palr is looked up in the internal table LINK builds
using the information in the coercion block.
The item field code
designates which field of the argument descriptor is being checked.
The field codes are defined as follows:
Field Code·

Condition

Check update
Check passing mechanism
Check argument type code
Check if compile-time constant
Check number of arguments
Check for return value
Check length of argument

1
2

3
4

5
6

A-62

April 1986

REL BLOCKS
If the fields of the formal/actual pair do not match,
LINK searches
the
internal table set up by the coercion block.
If the table does
not specify an action to take in the event of such a mismatch,
LINK
issues an informational message.
If the formal/actual pair differs in
more than one field then LINK takes the most severe action specified
for the mismatches.
If an actual/formal pair differ and no coercion block has been seen,
LINK ignores the difference.
If the caller has specified a descriptor
block but the subroutine has not, or if the subroutine has specified a
descriptor and the caller has not, LINK does not flag the condition as
an error and does not take any special action.
If LINK finds an entry in its
internal table for
a particular
actual/formal mismatch, it uses the action code found in the entry to
select one of the following five possible responses:
Code (18 Bits)

Action
Informational message

Warning

Error

Reserved
for
the specific conversion
of
static descriptor pointers (in the argument
list)
into
addresses.
The
descriptor
pointers are supplied by FORTRAN blocks of
types 112x.
NOTE
The
actual
conversion
process
involves the following actions:
•

If byte descriptor's P field
is
not word-aligned, issue a warning
and continue.

•

pick up word address of start
string.

•

Put the address of the string
into
the
associated argument
block in place of the address of
the string descriptor.

Suppress the message.

5-777776

Reserved

777777

Fatal error

These messages can be displayed or suppressed.
Refer
descriptions of the /ERRORLEVEL and /LOGLEVEL switches.

A-63

the

April 1986

REL BLOCKS
Block Type 1131 (TWOSEG Redirection Block)

I======~==============================================1

1131

Long Count

1-----------------------------------------------------1
1

Name of PSECT for low segment, or

/-----------------------------------------------------1
Name of PSECT for high segment, or
~

1=====================================================1

where each PSECT name has the form:
I====================================~================1
1
SIXBIT Symbol Name
1

1=====================================================/
or
~

5 6

17 18

/=======================================================1
1
~
1 Reserved for DIGITAL, MBZ
1 Long Count
1
1--------------------------------------------------------I
1
First word of SIXBIT Symbol Name
1
1--------------------------------------------------------I
1
Second word of SIXBIT Symbol Name
1
1-------------------------------------------------------I

1-------------------------------------------------------I
1
Nth word of SIXBIT Symbol Name
1
1=======================================================1
Block Type 1131 permits TWOSEG REL modules to be loaded into PSECTs by
a compiler.
You must redirect both the high and the low segment, you
cannot redirect one or the other. Also, you cannot redirect both the
high and low segment into the same PSECT.
This block does not affect the
modules to be loaded.

LINK

V6.~

current

A-64

module,

but

all

subsequent

April 1986

REL BLOCKS
Block Type 1149 (PL/l debugger information)

I=============~=======================================1

1
1140
1
Long count
1
1-----------------------------------------------------1
1
Data Word
1
1-----------------------------------------------------1

1-----------------------------------------------------1
1
Data Word
I
1=====================================================1

Block type 1140 is ignored by LINK.

A-65

April 1986

REL BLOCKS
Block Type

116~

(Extended Sparse Data Initialization Block)

======================~============:=================~=

1160

Long

R I FIB I P I 0 I SYMLEN

Count

PSECT

Symbol (SYMLEN words)
Origin

Address

Repetition Count if R=l
Fill Count if F=1
Fill Byte if F=l
I
Byte Count if B=l
I--------------------------~--------------------------I
I
Data Bytes
I
==============================:=============:~=:=======

Block Type 1160 supports the loading of data into different PSECTs and
sections.
This REL block allows separate program units to load data
into different bytes in the same word of memory at different times
during the loading process.
Block Type 1160 fields are described below.
Field Name

Position

Bit

If R is
is a I-bit field.
one, the Repetition Count word
exists. If R is zero, the
Repetition Count is assumed to
be 1.

Bit 1

is a I-bit field.
If F is
one, the Fill Count and Fill
Byte words exist.
If F is
zero, no fill is used.

Bit 2

is a I-bit field.
If B is
one,
the
Byte Count word
exits. If B is zero, one Data
Byte is assumed.

Bits 3-8

is a 6-bit field. This is the
position within the word where
the first byte is
to
be
stored.

Unused

Bit 9

is an unused bit that must
zero.

LINK V6.0

Description

A-66

April 1986

REL BLOCKS
Field Name

position

SYMLEN

Bits 10-17

is an 8-bit field.
SYMLEN is
the length in words of the
global symbol to be used to
calculate the address to store
the byte string. If SYMLEN is
zero,
there
is no global
symbol.
The value of
the
symbol is added to the origin
address. The symbol must be
completely defined before this
addition occurs.

PSECT

Bits 18-35

is an l8-bit field.
PSECT is
the
PSECT to relocate the
Origin Address against.
The
relocation
is
30-bit.
If
PSECT is zero, the
Origin
Address is absolute.

Symbol

Bits 0-35

is a SIXBIT symbol name of the
length specified in SYMLEN.
The value of this symbol
is
added to the Origin Address.
~ The
symbol must be defined
when the block is seen, or a
fatal error occurs.

Bits 0-5

is a 6-bit field.
S is
size of the data bytes.

Origin Address

Bits 6-35

is a 30-bit field.
Origin
Address is the address where
LINK begins to store
Data
Bytes.

Repetition Count

Bits 0-35

is a 36-bit field.
If flag
bit R is one, Repetition Count
exists and contains the number
of times to repeat the data
store.
The Data Bytes are
stored and the fill operation
is performed as many times as
specified in the Repetition
Count.

Fill Count

Bits 0-35

is a 36-bit field.
If flag
bit
F is one,
Fill Count
exists and specifies how many
times to store the Fill Byte
after storing Data Bytes.

LINK V6.0

Description

A-67

the

April 1986

REL BLOCKS
Field Name

Position

Fill Byte

Bits "-35

Description
is a 36-bit field.
If flag
bit F is one, Fill Byte exists
and
contains
the
right
justified value to be used in
the fill operation.

Byte Count

is a 36-bit field.
If flag
bit B is one, Byte Count exits
and specifies the number of
Data Bytes to be stored.

Data Bytes

are the data to be stored, of
the length specified by the
Byte Count, or 1 if flag bit B
is not set.
This data is
stored left-justified, packed
as many to a word as fit
without overlapping a
word
boundary.

LINK V6."

A-68

April 1986

REL BLOCKS
Block Type Greater Than 3777 (ASCIZ)

1=======================================================1
1 ASC I I 1 ASC I I 1 ASC I I 1 ASC I I 1 ASC I I 1 ~ 1
1-------------------------------------------------------I
1 ASC I I 1 ASC I I 1 ASC I I 1 ASC I I 1 ASC I I 1 ~ I
1-------------------------------------------------------I
1-------------------------------------------------------I
1 ASCII 1 ASCII 1 ASCII 1 ASCII 1
~
1 ~ 1
I======~==~~===========================~================1

When LINK reads a number larger than 3777 in the left half of a REL
Block header word, the block is assumed to contain ASCIZ text. If the
module containing the text is being loaded, LINK reads the ASCII
characters as if they were a command string, input from the user's
terminal.
LINK reads the string as five 7-bit ASCII characters per word; bit 35
of each word is ignored. The string and the block end when the first
null ASCII character (~00) is found in the fifth 7-bit byte of a word
(bits 28-34).
After loading the current REL file, LINK processes text statements in
the reverse order in which they are encountered -- from the end to the
beginning of a module. For example, the first, second, and third
statements from the beginning of a module are processed third, second,
and first. As a result, search requests may be processed in the
reverse order of entered /SEARCH switches. Keep this in mind when
specifying the order the modules are to be searched.

A-69

April 1986

APPENDIX B
LINK MESSAGES

This appendix lists all of LINK's messages.
(The messages from the
overlay handler, which have the OVL prefix, are given in Chapter 5.)

B.l

DESCRIPTION OF MESSAGES

Section B.2 lists LINK's messages. For each message, the last three
letters of the 6-letter code, the level, the severity, and its
medium-length message are given in boldface. Then, in lightface type,
comes the long message.
When a message is issued,the three letters are suffixed
letters LNK, forming a 6-letter code of the form LNKxxx.

the

The level of a message determines whether it will be issued to the
terminal, the log file, or both. You can use the /ERRORLEVEL and
/LOGLEVEL switches to control message output. For some messages an
asterisk (*) is given for the level or severity. This means that the
value is variable, and depends on the conditions that generated the
message.
The severity of a message determines whether the load will be
terminated when the message is issued. Table B-1 lists the severity
codes used in LINK, along with their meanings. The /SEVERITY switch
provides a means for lowering the severity that is considered fatal.
The severity also determines the first character on the message line
printed to the terminal. This character can then be detected by the
batch system. For all informational messages, the character is [.
Warnings use %, and fatal errors use ?

B-1

LINK MESSAGES
Table B-1
Severity Codes
Code

Meaning

1-7

Informational;
messages of this
severity
indicate LINK's progress through the load.

generally

8-15

warning; LINK is able to recover by itself
the load.

and

continue

Warning if timesharing, but fatal and stops
running under batch.

the

load

Fatal; LINK can only partially recover and continue the
load.
The loaded program may be incorrect. Undefined
symbols cause this action.

This is for file access errors.
Under batch, this is
fatal and stops the load. Under timesharing, this is a
warning, and LINK
prompts
for
the
correct
file
specification if possible.

Always fatal;

LINK stops the load.

The /VERBOSITY switch determines whether the medium-length and long
messages are issued. If you use /VERBOSITY:SHORT, only the 6-1etter
code, the level, and the severity are issued.
If
you
use
/VERBOSITY:MEDIUM, the medium-length message is also issued. If you
use /VERBOSITY: LONG , the code, level, severity, medium-length message,
and long message are issued.
Those portions of the medium-length messages enclosed in braces ({ and
}) are optional, and are only printed in appropriate circumstances.
Those portions of the medium-length messages enclosed in square
brackets are filled in at runtime with values pertinent to the
particular error.
Table B-2 describes each of these bracketed
quantities.

B-2

LINK MESSAGES

Table B-2
Special Message Segments
[area]

The name of one
management areas.

[date]

The date when LINK is running.

[decimal]

A decimal number, such as a node number.

[device]

A device name.

[file]

A file specification.

[label]

An internal label in LINK.

[memory]

A memory size, such as 17P.

[name]

The name of the loaded program or a node
overlaid program.

[octal]

An octal number, such as a symbol value.

[reason]

The reason for a file access failure, one of the
messages shown in Section B.3.

[switch]

The name of a switch associated with the error.

[symbol]

The name of a symbol, such as
common block name.

[type]

The type or attributes associated with a symbol.

LINK's

internal

The octal status codes that appear in TOPS-IO messages
more thoroughly in the TOPS-IO Monitor Calls Manual.

memory

subroutine

are

described

Whenever possible, LINK attempts to indicate the module and file
associated with an error.
This information represents the module
currently being processed by LINK, and may not always be the actual
module containing the error.
For instance, if LINK detects a
multiply-defined symbol, either value may be the incorrect one.
In
this case, LINK reports only the second (and subsequent) redefinition
and the module containing it.

B-3

LINK MESSAGES
B.2

LIST OF MESSAGES
Code

Lev

Sev

ABT

Message
Load aborted due to %LNKTMA
/ARSIZE: needed was [decimal]

errors,

max.

You loaded programs containing more ambiguous
subroutine requests than can fit in the tables
of one or more overlay links.
You received a
LNKARL message for each ambiguous request, and a
LNKTMA message for each link with too many
requests.
You can solve this problem by using
the /ARSIZE switch just before each /LINK switch
to expand the tables separately.
AIC

Attempt to increase size of {blank common}
{common [symbol]} from [decimal] to [decimal]
{Detected in module [symbol] from file [file]}
FORTRAN common areas cannot be expanded once
defined.
Either load the module with the
largest definition first, or use the /COMMON:
switch to reserve the needed space.

AMM

Argument mismatch in argument [decimal] in call
to routine [symbol] called from module [symbol]
at location [octal]
The caller supplied argument does not match
argument expected by the callee.

AMP

the

ALGOL main program not loaded
You loaded ALGOL procedures, but
no
main
The
program.
missing
start
address and
undefined symbols will cause termination of
execution.

ANM

Address not in memory
LINK expected a particular user address to be in
memory, but it is not there.
This is an
internal LINK error.
This message is
not
expected to occur.
If it does, please notify
your Software Specialist or send a Software
Performance Report (SPR) to DIGITAL.

ARL

Ambiguous request in link
[decimal]
{name
[name]} for [symbol] defined in links [decimal],
[decimal], •••
More than one successor link can satisfy a call
from a predecessor link. The predecessor link
requested an entry point that is contained in
two or more of its successors.
You should
revise your overlay structure to remove the
ambiguity.

The level and severity of this
message
is
determined
by
compiler-generated coercion block. See Block Type 1130 in Appendix A.
B-4

LINK MESSAGES
Code

Lev

Sev

Message
If you execute the current load, one of the
following will occur when the ambiguous call is
executed:
•

If only one module satisfying the request is
in memory, that module will be called.

•

If two or more modules satisfying
the
request are in memory, the one with the most
links in memory will be called.

•

If no modules satisfying the request are in
memory, the one with the most links in
memory will be called.

If a module cannot be selected by the methods 2
or 3 above, an arbitrarily selected module will
be called.
AZW

Allocating zero words
LINK's memory manager was called with a request
for 0 words.
This is an internal LINK error.
This message is not expected to occur.
If it
does, please notify your Software Specialist or
send a Software Performance Report (SPR) to
DIGITAL.

cao

Cannot build overlays outside section 0.
You tried to build an overlay structure for a
program that is either too large to fit in
Section 0 or is loaded outside Section 0 by
default.
Check the commands input to LINK and
the language compiler.

CCD

CPU conflict
{Detected in module [symbol] from file [file]}
You
have
loaded
modules
compiled
with
conflicting CPU specifications, such as loading
a MACRO program compiled with the statement
.DIRECTIVE
KL10
and another compiled with
.DIRECTIVE KI10. Recompile the affected modules
with compatible CPU specifications.

CCE

Character constant not word aligned in call to
routine [routine] called from module [module] at
location [address]
LINK detected a character constant that did not
begin on a word boundary. This error probably
results from a language translator error.
This
error is not expected to occur. If it does,
please notify your Software Specialist or send a
Software Performance Report (SPR) to DIGITAL.

LINK V6.0

8-5

April 1986

•

LINK MESSAGES
Code

Lev

Sev

CCS

Message
Cannot create section [octal]
LINK is unable to create the specified section.
This could be because your system does not have
extended addressing hardware, or because there
are insufficient resources to create a section.

CFS

Chained fix ups have been suppressed
The specified PSECT grew beyond the address
specified In the /LIMIT switch. The program is
probably incorrect. Use the /MAP or /COUNTER
switch to check for accidental PSECT overlaps.
Refer to Section 3.2.2 for more information
about the /LIMIT switch.

CLF

Closing log file, continuing on file [file]
You have changed the log file specification.
The old log file is closed; further log entries
are written in the new log file.

CM6

Cannot mix COBOL-68 and COBOL compiled code
{Detected in module [symbol] from file [file]}
You cannot use COBOL-68 and COBOL files
in the
same load. Compile all COBOL programs with the
same compiler and reload.

CM7

Cannot mix COBOL-74 and COBOL compiled code
{Detected in module [symbol] from file [file]}
You cannot use COBOL-74 and COBOL files in the
same load. Compile all COBOL programs with the
same compiler and reload.

CMC

Cannot mix COBOL-68 and COBOL-74 compiled code
{Detected in module [symbol] from file [file]}
You cannot use COBOL-68 and COBOL-74 files in
the same load. Compile all COBOL programs with
the same compiler and reload.

CMF

COBOL module must be loaded first
{Detected in module [symbol] from file [file]}
You are loading a mixture
files
and
other files.
COBOL-compiled files first.

CMP

of COBOL-compiled
Load one of the

Common [symbol] declared in multiple PSECTS
{Detected in module [symbol] from file [file]}
You cannot load modules produced by FORTRAN with
modules produced by G-floating FORTRAN. Compile
all FORTRAN modules the same way, then reload.

LINK V6.0

B-6

April 1986

LINK MESSAGES
Code

Lev

Sev

Message

CMX

Cannot mix G-floating FORTRAN compiled code with
FORTRAN compiled code
{Detected in module [symbol] from [file]}
You loaded a module which specified that the
named common block must be loaded in a PSECT
which is not compatible with the PSECT in which
it was originally loaded. Compile the module
with the common in the same PSECT as the
original.

CNW

Code not yet written at [label]
You attempted to use an unimplemented feature.
This is an internal LINK error. This message is
not expected to occur.
If it does, please
notify
your Software Specialist or send a
Software Performance Report (SPR) to DIGITAL.

COE

Both
CONCATENATE
and
OVERLAY
attributes
specified for PSECT [name]
{Detected in module [symbol] from file [file]}

One of the modules you loaded explicitly sets an
attribute for the named PSECT which conflicts
with the declaration of PSECT attributes in the
current module. Check the compiler switches or
assembly language directives that were used in
the generation of this module.
COF

Cannot open file [file]

LINK cannot open the specified file for input.
CPU

Module incompatible with specified CPU
{Detected in module [symbol] from file [file]}
The module you are attempting to load does not
contain a .DIRECTIVE for any of the CPUs you
specified with the /CPU switch.
Recompile the
module with the proper .DIRECTIVE, or use a
different /CPU switch.

CRS

Creating section [octal]
LINK prints this informational message when a
module is loaded into a new section.
The
message is printed only if you have specified
/ERROR:0.

CSF

Creating saved file
LINK is generating your executable (.EXE) file.

DEB

[name] execution
LINK is beginning program execution at the named
debugger.

LINK V6.0

B-7

April 1986

LINK MESSAGES
Code

Lev

Sev

DLT

Message
Execution deleted
Though you have asked for program execution,
LINK
cannot
proceed due to earlier fatal
compiler or LINK errors. Your program is left
in memory or in an executable file.

DNS

Device not specified for switch [switch]
You used a device switch (for example, /REWIND,
/BACKSPACE), but LINK cannot associate a device
with the switch. Neither LINK's default device
nor any device you gave with the /DEFAULT switch
can apply. Give the device with or before the
switch (in the same command line).

DRC

Decreasing relocation counter [symbol]
from
[octal] to [octal]
{Detected in module [symbol] from file [file]}
You are using the /SET switch to reduce the
value of an already defined relocation counter.
Unless you know exactly where each module is
loaded, code may be overwritten.

DSC

Data store to common [symbol] not in link number
[decimal]
{Detected in module [symbol] from file [file]}
You loaded a FORTRAN-compiled module with DATA
statement assignments to a common area. The
common area is already defined in an ancestor
link.
Restructure the load so that the DATA
statements are loaded in the same link as the
common area to which they refer.

DSL

Data store to location [octal]
not in link
number [decimal]
{Detected in module [symbol] from file [file]}
You have a data store for an absolute location
outside the specified link.
Load the module
into the root link.
NOTE
If the location is less than 140, this
message has level 8 and severity 8.

•
DUZ

Decreasing undefined symbol count below zero
LINK's undefined symbol
count
has
become
negative.
This message is not expected to
occur. If it does, please notify your Software
Specialist or send a Software Performance Report
(SPR) to DIGITAL.

8-8

April 1986

LINK MESSAGES
Code

Lev

Sev

EAS

Message
Error creating area AS
[file]

overflow

file

[reason]

LINK could not make the ALGOL symbol table on
disk. You could be over your disk quota, or the
disk could be full or have errors.
ECE

Error creating EXE file [reason] [file]
LINK could not write the saved file on disk.
You could be over your disk quota, or the disk
could be full or have errors.

EGO

Emergency GETSEG done
LINK has expanded its low segment so large that
one of its larger high segments will not now fit
1n memory. LINK will attempt to shrink its
internal tables so that the GETSEG will succeed
and loading continue.

EHC

Error creating area HC
[file]

overflow

file

[reason]

LINK could not write your high-segment code on
disk. You could be over your disk quota, or the
disk could be full or have errors.
ElF

Error for input file
[file]

Status

[octal]

for

file

A read error has occurred on the input file.
Use of the file is terminated and the file is
released.
ELC

Error creating area LC
[file]

overflow

file

[reason]

LINK could not write your low-segment code on
the disk. You could be over your disk quota, or
the disk could be full or have errors.
ELF

End of log file
LINK has finished writing your
file is closed.

ELN

log

file.

The

End of link number [decimal] {name [name]}
The link is loaded.

ELS

Error creating area LS
[file]

overflow

file

[reason]

LINK could not write your local symbol table on
the disk. You could be over your disk quota, or
the disk could be full or have errors.

8-9

April 1986

LINK MESSAGES
Code

Lev

Sev

EMS

Message
End of MAP segment
The map file is completed and closed •

EOE

• EXE file output error Status [octal]
[f ile]

for

file

LINK could not write the saved file on the disk.
EOI

Error on input Status [octal] for file [file]
An error has been
named file.

EOO

detected

reading

the

while

writing

the

Error creating overlay file [reason] [file]
LINK could not write the
disk.

ESN

while

Error on output [file]
An error has been
named file.

EOV

detected

overlay

file

the

Extended symbol not expected
Long symbol names (more than six characters) are
not implemented.
This message is not expected
to occur.
If it does, please notify your
Software
Specialist
or
send
a
Software
Performance Report (SPR) to DIGITAL.

ETP

Error creating area TP
[file]

overflow

file

[reason]

LINK could not make the type checking area on
disk. You are over your disk quota, the disk is
full, or the disk has errors.
EXP

Expanding low segment to [addr]
This informational message is printed when
expands the low segm~nt memory allocation.

EXS

LINK

EXIT segment
LINK is in the last stages of loading your
program (for example, creating .EXE and symbol
files, preparing for execution if requested) •

•
FCF

Final code fixups
LINK is reading one or both segment overflow
files backwards to perform any needed code
fixups.
This may cause
considerable
disk
overhead, but occurs only if your program is too
big for memory.

LINK V6.0

8-10

April 1986

LINK MESSAGES
Code

Lev

Sev

FEE

Message
ENTER error [reason]

[file]

See Section B.3 for the list
messages.
FIN

possible

long

LINK finished
LINK is finished.
Control
is passed to the
monitor, or to the loaded program for execution.

FLE

LOOKUP error [reason]

[file]

See Section B.3 for the list
messages.

possible

long

•
FRE

RENAME erro r

[reason]

[f i 1 e]

See Section B.3 for the list
messages.

possible

long

•
FSN

FUNCT.

subroutine not loaded

During final processing of your root link,
LINK
found
that the FUNCT.
subroutine was not
loaded.
This would cause an infinite recursion
if your program were executed.
The FUNCT.
subroutine is requested by the overlay handler,
and
is usually loaded from a default system
library.
Either you prevented searching of
system libraries,
or you did not load a main
program from an overlay-supporting compiler into
the root link.
FTB

Fullword value [symbol]

truncated to halfword

This message is printed when a symbol that has a
value greater than 777777 is used to resolve a
halfword reference. This warning message helps
you to be sure that global addresses are used
properly throughout the modules in a load.
GSE

GETSEG error [reason]

[file]

See Section B.3 for the list
messages.
BCL

possible

long

8igh segment code not allowed in an overlay link
{Detected in module [symbol] from file [file]}
You have attempted to
load high segment code
into an overlay link other than the root.
Any
high segment code in an overlaid program must be
in the root.

B-ll

April 1986

LINK MESSAGES
Code

Lev

Sev

Message

HSL

Attempt to set high segment origin too low
{Detected in module [symbol] from file [file]}
You have'set the high-segment counter to a page
containing low-segment code. Reload, using the
/SET:.HIGH.:n switch, or (for MACRO programs)
reassemble after changing your TWOSEG pseudo-oPe

HTL

Symbol hash table too large
Your symbol hash table is larger than the
maximum LINK can generate
(about 50P). This
table size is an assembly parameter.
This
message is not expected to occur. If it does,
please notify your Software Specialist or send a
Software Performance Report (SPR) to DIGITAL.

lAS

Error inputting area as Status [octal] for
[file]
An error occurred while
symbol table.

ICB

reading

the

file
ALGOL

Invalid chain REL block (type 12)
link number
[octal]
{Detected in module [symbol] from file [file]}
REL block type 12
(Chain), generated by the
MACRO pseudo-op .LINK and .LNKEND, must contain
a number from 1 to 100
(octal)
in its first
word. The link word is ignored.

IDM

Illegal data mode for device [device]
You specified an illegal combination of device
and data mode (for example, terminal and dump
mode). Specify a legal device.

IHC

Error inputting area HC Status [octal] for
[file]
in

your

Error inputting area LC Status [octal] for
[file]

file

your

Error inputting area LS Status [octal] for
[file]

file

An error occurred while reading
symbol table.

local

An error occurred
high-segment code.
ILC

An error occurred
low-segment code.
ILS

IMA

while

reading

file

reading

your

Incremental maps not yet available
The INCREMENTAL keyword for the /MAP switch
not implemented. The switch is ignored.

8-12

April 1986

LINK MESSAGES
Code

Lev

Sev

IMI

Message
Insufficient memory to initialize LINK
LINK needs more memory than is available.

IMM

[Decimal]
[file] }

included modules

missing

{from

file

You have requested with the /INCLUDE switch that
the named modules (if any) be loaded. Specify
files containing these modules.
INS

I/O data block not set up
LINK attempted a monitor call
(for example,
LOOKUP, ENTER) for a channel that is not set up.
This is an internal LINK error. This message is
not expected to occur.
If it does, please
notify your Software Specialist or send
a
Software Performance Report (SPR) to DIGITAL.

IOV

Input error for overlay file Status [octal]
file [file]

for

An error occurred when reading the overlay file.
IPO

Invalid Polish operator [octal]
{Detected in module [symbol] from file [file]}
You are attempting to load a file containing an
invalid
REL Block Type 11
(Polish).
This
message is not expected to occur.
If it does,
please notify your Software Specialist or send a
Software Performance Report (SPR) to DIGITAL.

IPX

Invalid PSECT index {for PSECT [symbol]}
{Detected in module [symbol] from file [file]}
A REL block contains
a
reference
to
a
nonexistent
PSECT.
This error is probably
caused by a fault
in the language translator
used
for the program.
This error is not
expected to occur. If it does, please notify
your Software Specialist or send a Software
Performance Report (SPR) to DIGITAL.

IRB

Illegal REL block type [octal]
{Detected in module [symbol] from file [file]}
The file is not in the proper binary format.
It
may have been generated by a translator that
LINK does not recognize, or it may be an ASCII
or. EXE .f i 1 e •

IRC

Illegal relocation counter
{Detected in module [symbol]

from file [file]}

One of the new style 1000+ block types has an
illegal relocation counter. This message is not
expected to occur~
If it does, please notify
your Software Specialist or send a Software
Performance Report (SPR) to DIGITAL.

B-13

April 1986

LINK MESSAGES
Code

Lev

Sev

Message

IRR

Illegal request/require block
{Detected in module [symbol] from file [file]}
One of the REL block types 1042 or 1043 is in
the wrong format.
This message is not expected
to occur.
If it does,
please notify your
SoftwareSpeqialist
or
send
a
Software
Performance Report (SPR) to DIGITAL.

ISM

Incomplete symbol in store operator in Polish
block (type 11)
{Detected in module [symbol] from file [file]}
The specified module contains an
incorrectly
formatted
Polish Fixup Block
(Type 11). The
store operator specifies a symbol fixup, but the
block ends before the symbol is fully specified.
This error is probably caused by a fault in the
language translator used for the program.
This
error is not expected to occur.
If it does,
please notify your Software Specialist or send a
Software Performance Report (SPR) to DIGITAL.

ISN

Illegal symbol name [symbol]
{Detected in module [symbol]

from file [file]}

The LINK symbol table routine was called with
the blank symbol. This error can be caused by a
fault in the language translator used for the
program. This message is not expected to occur.
If it does,
please
notify
your
Software
Specialist or send a Software Performance Report
(SPR) to DIGITAL.
ISP

Incorrect symbol pointer
There is an error in the global symbol table.
This is an internal LINK error.
This message is
not expected to occur.
If
it does,
please
notify
your Software Specialist or send a
Software Performance Report (SPR) to DIGITAL.

ISS

Insufficient space for symbol table after
[symbol] -- table truncated

PSECT

There is insufficient address space for the
symbol table between the named PSECT and the
next higher one or the end of the address space.
Restructure
your
PSECT
layout
to
allow
sufficient room for the symbol table, or use
/UPTO to allow more room.
IST

Inconsistency in switch table
LINK has found errors in the switch table passed
from
the SCAN module.
This is an internal
errore
This message is not expected to occur.
If
it
does,
please notify your Software
Specialist or send a Software Performance Raport
(SPR) to DIGITAL.

B-14

April 1986

LINK MESSAGES
Code

Lev

Sev

ITB

Message
Invalid text in ASCII block from file [file]
LINK has failed to complete the processing of an
ASCII text REL block from the named file. This
is an internal· error.
This message is not
expected to occur.
If it does, please notify
your Software Specialist or send a Software
Performance Report (SPR) to DIGITAL.

ITP

Error inputting area TP
{Status [octal]} for file [file]
An error occurred while reading in the type
checking area. The status is represented by the
right half of the I/O status word. Refer to the
TOPS-10
Monitor
Calls
Manual
for
more
information.

IUU

Illegal user UUO at PC [octal]
LINK's user UUo (LUUO) handler has detected an
illegal UUO.
This is an internal error. This
message is not expected to occur. If it does,
please notify your Software Specialist or send a
Software Performance Report (SPR) to DIGITAL.

IVC

Index validation check failed at address [octal]
The range checking of LINK's internal tables and
arrays failed.
The address given is the point
in a LINK segment at which failure occurred.
This is an internal error. This message is not
expected to occur. If it does, please notify
your Software Specialist or send a Software
Performance Report (SPR) to DIGITAL.

JPB

Junk at end of Polish block
{Detected in module [symbol] from file [file]}
The specified module contains an incorrectly
formatted Polish Fixup Block (Type 11). Either
the last unused halfword (if it exists)
is
nonzero, or there are extra halfwords following
all valid data.

LOS

LOAD segment
The LINK module
processing.

LFB

LNKLOD

LINK V6.0

its

LINK log file begun on [date]
LINK is creating your log file as
defining the logical name LOG:.

LFC

beginning

result

LINK is continuing your log file as a result
the /LOG switch.

Log file continuation

B-15

April 1986

LINK MESSAGES
Code

Lev

Sev

LFI

Message
Log file initialization
LINK is beginning your log file as a
the /LOG switch.

LII

result

Library index inconsistent, continuing
REL Block Type 14 (Index) for a MAKLIB
generated library file is inconsistent. The
library is searched, but the index is ignored.

LIN

LINK initialization
LINK is beginning its processing by initializing
its internal tables and variables.

LMM

Length mismatch for argument [decimal]
in call
to routine [symbol] called from module [symbol]
at location [octal]
The length of the argument passed by the caller
does not match what the called routine expects
it to be.

LMN

Loading module [symbol] from file [file] LINK is
loading the named module.

LNA

Link name [name] already assigned to link number
[decimal]
You used this name for another link.
different name for this link.

LNL

Specify

Link number [decimal] not loaded
The link with this number has not yet been
loaded.
Tbe /NODE switch is ignored. If you
have used link numbers instead of link names
with the /NODE switch, you may have confused the
link numbers. To avoid this, use link names.

LNM

Link number [decimal] not in memory
LINK cannot find the named link in memory. This
is an internal error.
This message is not
expected to occur. If it does, please notify
your Software Specialist or send a Software
Performance Report (SPR) to DIGITAL.

The level and severity of this message is determined by a
compiler-generated coercion block.
See Block Type 1130 in
Appendix A.
B-16

April 1986

LINK MESSAGES
Code

Lev

Sev

LNN

Message
Link name [name] not assigned
The name you gave with the /NODE switch is not
the name of any loaded link. The switch is
ignored.

LNS

Low segment data base not same size
The length of LINK's low segment differs from
the length stored in the current LINK high
segment. This occurs if some but not all of
LINK's
.EXE files have been updated after
rebuilding LINK from sources.
Update all of
LINK's .EXE files.

LSM

/LINK switch missing while loading
[decimal] -- assumed

link

number

Your use of the /NODE switch shows that you want
to begin a new overlay link, but the current
link is not yet completely loaded. LINK assumes
a /LINK switch immediately preceding the /NODE
switch, and loads the link
(without a link
name) •
LSS

{No} Library search
{[symbol] [octal]

symbols

(entry

po ints)

The listed symbols and their values (if any) are
those that are library search entry points.
MDS

Multiply-defined global symbol [symbol]
{Detected in module [symbol] from file [file]}
Defined value = [octal], this value = [octal]
The named module contains a new definition of an
already
defined
global
symbol.
The old
definition is used.
Make
the
definitions
consistent and reload.

MEF

Memory expansion failed
LINK cannot
expand
memory
further.
All
permitted overflows to disk have been tried, but
your program is still too large for available
memory.
A probable cause is a large global
symbol table, which cannot be overflowed to
disk.
It may be necessary to restructure your
program, or use overlays, to alleviate this
problem.

MMF

Memory manager failure
The internal memory manager in LINK has failed a
consistency check. This error should not occur.
If it does, contact your software specialist or
send a Software Performance Report
(SPR) to
DIGITAL.

LINK V6.0

8-17

April 1986

LINK MESSAGES
Code

Lev

Sev

MOV

Message
Moving low segment to expand area [area]
LINK is rearranging its low segment to make more
room for the specified area. Area is one of the
following:
AS ALGOL symbol table
BG bound global symbols
DY dynamic free memory
FX fixup area
GS global symbol table
HC your high-segment code
LC your low-segment code
LS local symbol tables
RT relocation tables

MPS

MAP segment
The LINK module LNKMAP is writing a map file.

MPT

Mixed PSECT and TWOSEG code in same module
{Detected in module [symbol] from file [file]}
This module contains both PSECT code and TWOSEG
code.
LINK cannot load such a module. Change
the source code to use PSECTs .HIGH.
and
.LOW.
as the high and low segments, and remove the
TWOSEG or HISEG pseudo-ops.

MRN

Multiple regions not yet implemented
The REGION keyword for the /OVERLAY switch
not implemented.
The argument is ignored.

MSN

Map sorting not yet implemented
Alphabetical or numerical sorting of the map
file is not implemented.
The symbols in the map
file appear in the order they are found
in the
REL files •

•
MSS

/MAXCOR:

set too small, expanding to [memory]

The current value of MAXCOR is too small
for
LINK to operate.
You can speed up future loads
of this program by setting the /MAXCOR switch to
this expanded size at the beginning of the load.
MTB

/MAXCOR:

too big, [memory] used

You are attempting to specify the /MAXCOR switch
so large that the low segment cannot fit before
the high segment. LINK will use only the core
indicated.

B-18

April 1986

LINK MESSAGES
Code

Lev

Sev

MTS

Message
/MAXCOR:
required

too

small,

least

[memory]

LINK needs more space than you gave with the
/MAXCOR switch. Give a new /MAXCOR switch with
at least the required size.
NAP

No store address in polish block (Type 11
1072)
{Detected on module [symbol] from R6 [file]}

The specified module contains an incorrectly
formatted polish fixup block (Type 11 or 1072).
The store operator specifies a memory fixup, but
the block ends before the address is specified.
This error is probably caused by a fault in the
language translator used for the program. This
error is not expected to occur.
If it does,
please notify your Software Specialist or send a
Software Performance Report (SPR) to DIGITAL.
NBR

Attempt to position to node before the root
The argument you gave for the /NODE switch would
indicate a link before the root link.
(For
example, from a position after the third link in
a path, you cannot give /NODE:-4.)

NEB

No end block seen
{Detected in module [symbol] from file [file]}
No REL Block Type 5 (End) was found in the named
module. This will happen if LINK finds two Type
6 blocks (Name) without an intervening end, or
if an end-of-file is found before the end block
is seen. LINK simulates the missing end block.
However,
fatal messages usually follow this,
because this condition usually indicates a bad
REL file.

NED

Non-existent device [device]
You gave a device that does not exist on this
system. Correct your input files and reload.

NHN

No high segment in non-zero section
You have attempted to load high segment
into a program with a non-zero section.
segments must reside in Section 0.

NPS

code
High

Non-existent PSECT [symbol] specified for symbol
table
You have specified the name of a PSECT after
which LINK should append the symbol table, but
no PSECT with that name was loaded.
Load the
named PSECT or specify an existing PSECT for the
symbols.

LINK V6.0

8-19

April 1986

LINK MESSAGES
Code

Lev

Sev

NSA

Message
No start address
Your program does not have a starting address.
This can happen if you neglect to load a main
program. Program execution, if requested, will
be suppressed unless you specified debugger
execution.

NSM

/NODE switch missing after /LINK switch
You used the ILINK switch, which indicates that
you want to begin a new overlay link, but you
have not specified a INODE switch to tell LINK
where to put the new overlay link.

NSO

No store operator in Polish block (type 11)
{Detected in module [symbol] from file [file]}
The specified module contains an incorrectly
formatted Polish Fixup Block (Type 11). Either
the block does not have a store operator, or
LINK was not able to detect it due to the
block's invalid format.
This error is probably
caused by a fault
in the language translator
used for the program.
This error is
not
expected to occur.
If it does, please notify
your Software Specialist or send a Software
Performance Report (SPR) to DIGITAL.

NVR

No value returned by routine [symbol]
from module [symbol] at location [octal]

called

The called routine does not return a value,
however the caller expected a returned value.
OAS

Error outputting area as Status [octal]
[file]
An error occurred while writing
symbol table.

OEL

out

for file

the

ALGOL

Output error on log file, file closed, load
continuing {Status [octal] for file [file]}
An error has occurred on the output file.
The
output file
is closed at the end of the last
data successfully output.

OEM

Output error on map file,
file closed,
continuing Status [octal] for file [file]

load

An error has occurred on the output file.
The
output file
is closed at the end of the last
data successfully output.

:j:

The level and severity of this -message is determined by a
compiler-generated coercion block.
See Block Type 1130 in
Appendix A.
B-20

April 1986

LINK MESSAGES
Code

Lev

Sev

OES

Message
Output error on symbol file, file closed,
continuing Status [octal] for file [file]

load

An error has occurred on the output file.
The
output file is closed at the end of the last
data successfully output.
OEX

Output error on XPN file, file closed,
continuing Status [octal] for file [file]

load

An error has occurred on the output file.
The
output file is closed at the end of the last
data successfully output.
OPD

OPEN failure for device [device]
An OPEN or INIT monitor call for the specified
device failed. The device may be under another
user's control.

OFN

Old FORTRAN (F40) module not available
{Detected in module [symbol] from file [file]}
The standard released version of LINK
support F40 code.

OFS

does

not

Overlay file must be created on a file structure
Specify a disk device for the overlay file.

ORe

Error outputting area HC Status [octal] for file
[file)
An error occurred
high-segment code.

ORN

while

writing

out

your

Overlay handler not loaded
Internal symbols in the overlay handler could
not be referenced.
If you are using your own
overlay handler, this is a user error; if not,
it is an internal error and is not expected to
occur. If it does, please notify your Software
Specialist or send a Software Performance Report
(SPR) to DIGITAL.

OLC

Error outputting area LC Status [octal] for file
[file]
An error occurred
low-segment code.

OLS

while

writing

out

your

Error outputting area LS Status [octal] for file
[file)
An error occurred while writing out
symbol table.

B-2l

your

local

April 1986

LINK MESSAGES
Code

Lev

Sev

OMB

Message
/OVERLAY switch must be first
The /OVERLAY switch must appear before you can
use any of the following switches: /ARSIZE,
/LINK, /NODE, /PLOT, /SPACE.
(It is sufficient
that the /OVERLAY switch appear on the same line
as the first of these switches you use.)

ONS

Overlays not supported in this version of LINK
LINK handles overlays with its LNKOVI and LNKOV2
modules.
Your installation has substituted
dummy versions of these.
You should request
that your installation rebuild LINK with the
real LNKOVI and LNKOV2 modules.

OOV

Output error for overlay file Status [octal]
file [file]
An error has occurred while writing the
file.

OS2

overlay

Overlay segment phase 2
LINK's module LNKOV2
file.

OSL

for

writing

your

overlay

Overlaid program symbols must be in low segment
You have specified /SYMSEG:HIGH or /SYMSEG:PSECT
when loading an overlay structure.
Specify
/SYMSEG:LOW or /SYMSEG:DEFAULT.

OTP

Error outputting area TP
{Status [octal] for file [file]}
An error occurred while
writing
out
the
typechecking area. The status is represented by
the right half of the I/O status word (refer to
the TOPS-10 Monitor Calls Manual) •

PAS

Area AS overflowing to disk
The load is too large to fit
into the allowed
memory and the ALGOL symbol table is being moved
to disk.

PBI

Program break
module [symbol]

[octal]
invalid {Detected
from file [file]}

The highest address allocated in the named
module is greater than 5l2P. This is usually
caused by dimensioning large arrays.
Modify
your programs or load list to reduce the size of
the load.

LINK V6e0

B-22

April 1986

LINK MESSAGES
Code

Lev

Sev

Message
Program too complex
[file]

load,

saving

file

Your program is too complex to load into
for one of the following reasons:

memory

•

There are page gaps between
below the high segment).

PSECTs

(except

•

There are PSECTs above
high segment.

origin

•

Your program will not fit
in memory
with LINK's final placement code.

•

One or more
attribute.

PSECTs

the

has

the

the
along

read-only

LINK has saved your program as an .EXE file on
disk and cleared your user memory.
You can use
a GET or RUN command to load the .EXE file.
PCX

Program too complex to load
run from file [file]

and

execute,

will

Your program is too complex to load into
for one of the following reasons:

memory

•

There are page gaps between
below the high segment).

PSECTs

(except

•

There are PSECTs above
high segment.

origin

•

Your program will not fit
in memory
with LINK's final placement code.

•

One or more
attribute.

PSECTs

the

has

the

the
along

read-only

LINK will save your program as an .EXE file on
disk and automatically run it, but the .EXE file
will not be deleted.
PEF

Premature end of file from file [file]
LINK found an end-of-file
inside a REL block
(that
is, the word count for the block extended
beyond the end-of-fi1e).
This error may be
caused by a
fault
in the language translator
used for the program.

B-23

April 1986

LINK MESSAGES
Code

Lev

Sev

PEL

Message
PSECT [symbol] exceeded limit of [octal]
The specified PSECT grew beyond the address
specified in the /LIMIT switch. The program is
probably incorrect.
Use the /MAP or /COUNTER
switch to check for accidental PSECT overlaps.
Refer to Section 3.2.2 for more information
about the /LIMIT switch.

PRC

Area HC overflowing to disk
The load is too large to fit
into the allowed
memory and your high-segment code is being moved
to disk.

PLC

Area LC overflowing to disk
The load is too large to fit
into the allowed
memory and your low-segment code is being moved
to disk.

PLS

Area LS overflowing to disk
The load is too large to fit
memory and your local

into

the

allowed

Possible modification of argument [decimal]
in
call to routine [symbol]
called from module
[symbol] at location [octal]

PMA

The caller has specified that the argument
should not be modified.
The called routine
contains code which may modify this argument.
In some cases this message will occur although
the argument is not actually modified by the
routine.
POT

Plotting overlay tree
LINK is creating your overlay tree file.

POV

PSECTs [symbol]
and [symbol]
address [octal] to [octal]

overlap

from

The named PSECTs overlap each other in the
indicated range of addresses.
If you do not
expect this message,
restructure your PSECT
origins with the /SET switch.

PTP

Area TP overflowing to disk
The load is too large to fit
into the allowed
memory and your argument typechecking tables are
being moved to disk.

The level and severity of this message is determined by a
compiler-generated coercion block.
See Block Type 1130 in
Appendix A.
LINK V6.0

B-24

April 1986

LINK MESSAGES
Code

Lev

Sev

Message

PTL

Program too long
{Detected in module [symbol]

from file [file]}

Your program extends beyond location 777777,
which is the highest location that LINK is
capable of loading. You may be able to make
your
program fit by moving PSECT or1g1ns,
lowering the high-segment origin, loading into a
single segment,
reducing the size of arrays in
your program, or using the overlay facility.
PUF

PAGE.

UUO failed, error code was [code]

UUO

Refer to the description of the PAGE.
the TOPS-10 Monitor Calls Manual.
RBS

REL block type [octal] too short
{Detected in module [symbol] from file [file]}
The REL block is inconsistent.
This may be
caused by incorrect output from a translator
(for example, missing argument for an
end
block). Recompile the module and reload.

RED

Reducing low segment to [memory]
LINK is reclaiming
internal tables.

RER

memory

{Ro} Request external
entry points)
{ [symbol] [octal]}

deleting

references

its

(inter-link

The listed symbols and their values
(if any)
represent subroutine entry points in the current
link.
RGS

Rehashing global symbol table from [decimal]
[dec imal]

LINK is expanding the global symbol table either
to a prime number larger than your /HASHSIZE
switch requested, or by about 50 percent.
You
can speed up future loads of this program by
setting /HASHSIZE this large at the beginning of
the load.
RLC

Reloc ctr.
initial value current value
{[symbol] [octal] [octal]}
The listed symbols and values represent the
current placement of PSECTs in your address
space.

B-25

April 1986

LINK MESSAGES
Code

Lev

Sev

RME

Message
REMAP error{,
incorrect}

high

segment

origin

may

The REMAP UUO to place your program's high
segment
has
failed.
This message is not
expected to occur. If it does, please notify
your Software Specialist or send a Software
Performance Report (SPR) to DIGITAL.
RUM

Returning unavailable memory
LINK attempted to return memory to the memory
manager,
but the specified memory was not
previously allocated.
This is an
internal
error.
This message is not expected to occur.
If it does, please
notify
your
Software
Specialist or send a Software Performance Report
(SPR) to DIGITAL.

RWA

80th READ-ONLY and WRITABLE attributes specified
for PSECT [name]

Symbol table fouled up
There are errors in the local symbol table.
Loading continues, but any maps you request will
not contain control section lengths. This is an
internal error. This message is not expected to
occur. If it does, please notify your Software
Specialist or send a Software Performance Report
(SPR) to DIGITAL.

SIF

Symbol insert failure, non-zero hole found
LINK's hashing algorithms failed; they
are
trying to write a new symbol over an old one.
You may be able to load your files in a
different order.
This is an internal error.
This message is not expected to occur.
If it
does, please notify your Software Specialist or
send a Software Performance Report (SPR) to
DIGITAL.

SMP

SIMULA main program not loaded
You loaded some SIMULA procedures or classes,
but no main program. Missing start address and
undefined symbols will terminate execution.

LINK V6.0

B-26

April 1986

LINK MESSAGES
Code

Lev

Sev

Message

SNC

Symbol [symbol]
already defined, but not as
common
{Detected in module [symbol] from file [file]}
You defined a FORTRAN common area with the same
name as a non-common symbol.
You must indicate
which definition you want.
If you want the
common definition, load the common area first.

SNL

Scanning new command line
LINK is ready to process the next command line.

SNP

Subroutine [symbol] in link number [decimal] not
on path for call from link number [decimal]
{name [name]}
The named subroutine is in a different path than
the
calling
link.
Redefine your overlay
structure so that the subroutine
is in the
correct path.

SNS

SITGO not supported
{Detected in module [symbol]
LINK does not support
produced by the SITGO
program by using SITGO.

SOE

from file [file]}

the REL file format
compiler.
Load your

Saved file output error Status [octal]
[file]

for

file

An error occurred in outputting the .EXE file.
SRB

Attempt to set relocation counter [symbol] below
initial value of [octal]
{Detected in module [symbol] from file [file]}
You cannot use the /SET switch to set the named
relocation counter below its initial value. The
attempt is ignored.

SRP

/SET: switch required for PSECT [symbol]
{Detected in module [symbol] from file [file]}
Relocatable PSECTS are not implemented; you must
specify an explicit absolute origin with the
/SET switch for the named PSECT.

SSN

Symbol table sorting not yet implemented
Alphabetical or numerical sorting of the symbol
table is not implemented. The symbols appear in
the order they are found.

B-27

April 1986

LINK MESSAGES
Code

Lev

Sev

SST

Message
Sorting symbol table
LINK is ,rearranging the symbol table, and if
required, is converting the symbols from the new
to old format as indicated on the /SYMSEG,
/SYFILE, or /DEBUG switch.

STC

Symbol table completed
The symbol table has been
according to the /SYMSEG,
switch.

STL

sorted and moved
/SYFILE, or /DEBUG

Symbol too long
A symbol specified in a REL block is larger than
the maximum allowed by LINK.

I
T13

LVAR REL block (type 13) not implemented
{Detected in module [symbol] from file [file]}
REL Block Type 13 (LVAR) is obsolete.
MACRO pseudo-op TWOSEG.

TDS

Use

the

Too late to delete initial symbols
LINK has already loaded the initial symbol
table.
To prevent this loading, place the
/NOINITIAL switch
before
the
first
file
specification.

TMA

Too many ambiguous requests in link [decimal]
{name [name]}, use /ARSIZE: [decimal]
{Detected in module [symbol] from file [file]}
You have more ambiguous subroutine requests
(indicated by LNKARL messages) than will fit in
the table for this link.
Continue loading.
Your load will abort at the end with a LNKABT
message; if you have loaded all modules, the
message will give the size of the needed /ARSIZE
switch for a reload.

TML

Too many links use /MAXNODE
You specified more overlay links than were
allowed by the current value for the /MAXNODE
switch.
Reload the program with a
larger
/MAXNODE value.

LINK V6.0

B-28

April 1986

LINK MESSAGES
Code

Lev

Sev

TMM

Message
Type mismatch seen for argument [decimal]
in
call to routine [symbol]
called from module
[symbol] at location [octal]
The data type of the argument passed by the
caller does not match what the called routine
expects.

TTF

Too many titles found
In producing the index for a map file,
LINK
found
more
program
names than there are
programs. The symbol table is in error.
This
is an internal error.
This message is not
expected to occur. If it does, please notify
your Software Specialist or send a Software
Performance Report (SPR) to DIGITAL.

UAR

Undefined assign for [symbol]
{Detected in module [symbol] from file [file]}
The named symbol was referenced in a REL Block
Type 100 (ASSIGN), but the symbol is undefined.
This is generated with the MACRO pseudo-op
.ASSIGN. The assignment is ignored. You should
load a module that defines the symbol.

UCB

Unknown common [symbol]

referenced

A reference was made to a common block that does
not exist.
UGS

{NO} Undefined global symbols {[symbol] [octal]
The listed symbols and their values
(if any)
represent symbols not yet defined by any module.
Each value is the first address in a chain of
references for the associated symbol.
If this message resulted automatically at the
end of loading, this is a user error.
In this
case, the load will continue, leaving references
to these symbols unresolved.

UNS

(type

Universal file REL block
supported from file [file]
Extraction of symbols from
file is not implemented.

MACRO

777)

not

universal

The level and severity of this message is determined by a
compiler-generated coercion block.
See Block Type 1130 in
Appendix A.
LINK V6.0

B-29

April 1986

LINK MESSAGES
Code

Lev

Sev

Message

URC

Unknown Radix-58 symbol code [octal] [symbol]
{Detected in module [symbol] from file [file]}
In a REL Block Type 2 (Symbols), the first 4
bits of each word pair contain the Radix-50
symbol code. LINK found one or more invalid
codes in the block. This error can be caused by
a fault in the language translator used for the
program.

URV

Unexpected return value in call to routine
[symbol] called from module [symbol] at location
[octal]
The called routine returns a value which was not
expected by the caller.

USA

Undefined start address [symbol]
You gave an undefined global symbol as the start
address. Load a module that defines the symbol.

USB

Undefined symbol in byte array (type 1004) block

LINK has detected an undefined global symbol in
a Type 1004 REL block. This global symbol is
used to relocate a byte pointer and must be
defined before the 1004 block that uses it is
seen. This error is probably the result of an
error
in
the language translator used to
generate the REL file.
USC

Undefined subroutine [symbol] called
number [decimal] {name [name]}

from

link

The named link contains a call for a subroutine
you have not loaded.
If the subroutine is
required for execution,
you
must
reload,
including the required module in the link.
USD

Undefined symbol [symbol] in
1160)

spare

data

(type

LINK has detected an undefined global symbol in
a Type 1160 REL block. This global symbol is
used to relocate a byte pointer and must be
defined before the 1160 block that uses it is
seen. This error is probably the result of an
error
in
the language translator used to
generate the REL file.

The level and severity of this message is determined by a
compiler-generated coercion block.
See Block Type 1130 in
Appendix A.
LINK V6.0

B-30

April 1986

LINK MESSAGES
Code

Lev

Sev

USI

Message
Undefined
[swi tch]

symbol

[symbol]

illegal

swi tch

You have specified an undefined symbol
to a
switch that can only take a defined symbol or a
number. Specify the correct switch value.
UUA

Undefined /UPTO:

address [symbol]

You gave the named symbol as an argument to the
/UPTO switch, but the symbol was never defined.
Load a module that defines the symbol, or change
your argument to the /UPTO switch.
VAL

Symbol [symbol]

[octal]

[type]

LINK has printed the specified symbol, its value
and its attributes as requested.
tINA

Wrong number of arguments in call to routine
[symbol] called from module [symbol] at location
[octal]
The number of arguments in the routine call
is
not the number of arguments expected by the
called routine.

XCT

[llame] execution
LINK is beginning execution of your program.

ZSV

Zero switch value illegal
You omitted required arguments for a switch (for
example, /REQUIRE with no symbols). Respecify
the switch.

B-31

April 1986

LINK MESSAGES
B.3

INDEXED MESSAGES

The following pages list the indexed messages issued with the LINK
messages LNKFEE,
LNKFLE,
LNKFRE, and LNKGSE.
The medium-length
messages in the table are substituted for the [reason]
field
in the
main messages.
The level and severity of these messages depend on the particular file
access error.
Thus, each indexed message includes the level and
severity actually assigned to the main message.
Idx

Lev

Sev

Message
(0) Illegal file name
One of the following conditions occurred:

The specified file name was illegal.

When updating a file,
the specified file
name did not match the file being updated.

The RENAME monitor call following
monitor call failed.

LOOKUP

(0) file was not found
The named file
existing file.

was

not

found.

Specify

(1) nc. directory for project-programmer number
The named directory does not e~ist on the named
file structure, or the project-programmer number
given was incorrect.

(2) protection failure
You do not have sufficient access privileges
use the named file.

(2) directory full
The directory on the DECtape has no room for the
file.
Delete some files
from the DECtape or
specify another device.

(3) file was being modified
Another job is currently modifying
file. Try accessing the file later.

the

named

(4) rename file name already exists
The named file already exists, or a different
file was specified on the ENTER monitor call
following a LOOKUP monitor call.

8-32

April 1986

LINK MESSAGES
Idx

Lev

Sev

Message
(5)

illegal sequence of UUOs

LINK has specified an
illegal sequence
of
monitor calls.
(For example, a RENAME without a
preceding LOOKUP or ENTER monitor call, or a
LOOKUP after an ENTER.)
This is an internal
error.
This message is not expected to occur.
If
it
does,
please notify your Software
Specialist or send a Software Performance Report
(SPR) to DIGITAL.

(6) bad UFD or bad RIB
One of the following conditions occurred:

A transmission, device
or
data
error
occurred
while
attempting to read the
directory or the RIB of the named file.

A hardware-detected device or data error was
detected while reading the named directory's
RIB or data block.

A software-detected data inconsistency error
was
detected
while
reading the named
directory's or file's RIB.

(7) not a saved file
The named
file
is not a
saved file.
This
message is not expected to occur.
If it does,
please notify your Software Specialist or send a
Software Performance Report (SPR) to DIGITAL.

(1~)

not enough memory

The system cannot supply enough memory to use as
buffers or to read in a program.
This message
is not expected to occur.
If
it does,
please
notify
your Software Specialist or send a
Software Performance Report (SPR) to DIGITAL.
11

(11) device not available
The named device
is currently not available.
This message
is not expected to occur.
If it
does, please notify your Software Specialist or
send a Software Performance Report
(SPR) to
DIGITAL.

(12) no such device
The named device does not exist.
This message
is not expected to occur.
If it does, please
notify your Software Specialist or send
a
Software Performance Report (SPR) to DIGITAL.

B-33

April 1986

LINK MESSAGES
Idx

Lev

Sev

Message
(13) not two re10c reg.

capability

The machine does not have
a
two-register
relocation capability.
This message can never
occur and is included only for completeness of
the LOOKUP, ENTER and RENAME error codes.
If it
does occur,
please
notify
your
Software
Specialist or send a Software Performance Report
(SPR) to DIGITAL.
14

(14) no room or quota exceeded
You have exceeded the quota of the
named
directory, or the entire capacity of the file
structure. Delete some files, or specify a
directory or structure with sufficient space.

(15) write lock error
Specify a
operator to

The named device is write-locked.
write-enabled device or ask the
write-enable the named device.

(16) not enough monitor table space
There is not enough internal monitor table space
for the named file.
Try the load at a later
time.

(17) partial allocation only
Because of the named directory's quota or the
available space on the file structure, the total
number of blocks requested
could
not
be
allocated. A partial allocation was given.

(2g) block not free on allocation
The block required by LINK is not available for
allocation. This message can never occur and is
included only for completeness of the LOOKUP,
ENTER and RENAME error codes. This message is
not expected to occur.
If it does, please
notify
your Software Specialist or send a
Software Performance Report (SPR) to DIGITAL.

(21) can't
directory

supersede

You have attempted
directory.
22

(enter)
to

supersede

existing
the

named

(22) can't delete (rename) a non-empty directory
You have attempted to delete a directory that is
not empty. This message can never occur and is
included only for completeness of the LOOKUP,
ENTER and RENAME error codes.
If it does occur,
please notify your Software Specialist or send a
Software Performance Report (SPR) to DIGITAL.

B-34

April 1986

LINK MESSAGES
Idx

Lev

Sev

Message

(23) SFD not found
One of the sub-file
path was not found.

directories

the

named

(24) search list empty
A LOOKUP or ENTER monitor call was performed on
generic device DSK:
and the search list is
empty.

(25) SFD nested too deeply
You have
directory
allowed.

attempted to
access
a
sub-file
nested deeper than the maximum level

(26) no-create on for specified SFD path
No file structure in your job's search list has
both the no-create bit and the write-lock bit
equal to zero, and has the named directory.

(27) segment not on swap space
A GETSEG monitor call was issued from a locked
low segment to a high segment which is not a
dormant, active or idle segment.
This message
can
never occur and is included only for
completeness of the LOOKUP, ENTER and RENAME
error codes.
If it does occur, please notify
your Software Specialist or send a Software
Performance Report (SPR) to DIGITAL.

(3~)

can't update file

A LOOKUP and ENTER monitor call was given to
update a file,
but the file cannot be updated
for some reason.
(For example, another user is
superseding it or the file was deleted between
the time of the LOOKUP and the ENTER).
31

(31) low segment overlaps high segment
The end of the low segment
beginning of the high segment.

above

the

(32) RUN not allowed when not logged in
An attempt has been made to run a program from a
not-logged-in job. This message is not expected
to occur.
If it does, please notify your
Software
Specialist
or
send
a
Software
Performance Report (SPR) to DIGITAL.

8-35

April 1986

LINK MESSAGES
Idx

Lev

Sev

Message
(33) file still has outstanding ENQ/DEQ locks
The ENQ/D&Q facility
has
been
used
for
simultaneous updating. of the named file, but
some ENQ/DEQ requests are still outstanding and
the file cannot be closed. This message is not
expected to occur.
If it does,
please notify
your Software Specialist or send a Software
Performance Report (SPR) to DIGITAL.

(34) bad .EXE file directory format
The named file has a bad .EXE format directory.
This message is not expected to occur.
If it
does, please notify your Software Specialist or
send a Software Performance Report
(SPR) to
DIGITAL.

(35).EXE format files must have .EXE extension
An attempt has been made to run an .EXE-format
file with a non-.EXE extension.
.EXE format
files (those with an internal directory)
must
have the extension .EXE. This message is not
expected to occur. If it does, please notify
your Software Specialist or send a Software
Performance Report (SPR) to DIGITAL.

(36)

.EXE file directory is too big

An attempt has been made to run an .EXE-format
file with a directory that is too large for the
monitor to handle. This message is not expected
to occur.
If it does, please notify your
Software
Specialist
or
send
a
Software
Performance Report (SPR) to DIGITAL.
37

(37) network capability exceeded for TSK:
The monitor's ability to accept another
connection has been exceeded.

(40) task is not available
The named task is not
existing task name.

network

available.

Specify

(41) undefined network node for TSK:
You have specified a network node that does not
exist.
Wait for the node to come up or specify
an existing network node.

([octal]) Unknown cause
This message indicates that a LOOKUP,
ENTER or
RENAME monitor call error occurred with an error
code larger in number than the errors LINK knows
about.
This message is not expected to occur.
If it does, please
notify
your
Software
Specialist or send a Software Performance Report
(S PR) to DIGITAL.

8-36

April 1986

APPENDIX C
JOB DATA AREA LOCATIONS SET BY LINK

LINK sets a number of locations between 40 and 140
(octal)
in the
user's program.
These locations are known as the Job Data Area
(commonly abbreviated to JOBDAT).
They are used by the TOPS-10
monitor.
In addition, two segment programs will have a vestigial Job
Data Area of eight words following the high segment origin.
Job Data Area
Address

Mnemonic

Use

.JB41

HALT if not specified otherwise.
Executes by LUUOs.

.JBERR

Right:

Number of errors during loading.

• JBDDT

Left:
Right:

Highest location occupied by DDT •
Start address of DDT if loaded.

115

• JBHRL

Left:
Right:

High segment length •
Highest address in high segment.

116

.JBSYM

Left:
Right:

Negative length of symbol table.
Address of table.

For extended symbol tables, this word contains a
positive value which is the pointer to the symbol
table vector (see Section 4.3).
117

.JBUSY

Left:
Right:

Negative length of undefined
symbol
table.
Address of undefined symbol table.

If 0, there is no undefined symbol table, or the
pointer to an extended symbol table is stored in
.JBSYM.
120

.JBSA

Left:
Right:

First free location in low segment.
Start address of program.

121

.JBFF

Right:

First free location in low segment.

124

.JBREN

Right:

Reenter address of program.

LINK V6.0

C-1

April 1986

JOB DATA AREA LOCATIONS SET BY LINK
Address

Mnemonic

Use

131

.JBOVL

Address of header block for
link in an overlaid program.

133

.JBCOR

Left:

137

.JBVER

Version number:
see description
switch in Section 3.2.2.

Highest location of low
with data.

the

root

segment

loaded

/VERSION

Vestigial Job Data Area
Offset

Mnemonic

Use

.JBHSA

Copy of .JBSA.

.JBH41

Copy of .JB4l.

.JBHCR

Copy of .JBCOR.

• JBHRH

LH:
RH:

• JBHVR

Copy of .JBVER •

• JBHNM

Prog ram Name •

.JBHSM

High segment symbol table, if any_

.JBHGA

High segment origin page in bits 9-17.

left half of .JBHRL •
right half of .JBREN.

C-2

April 1986

INDEX

Abbreviating
switches, 3-4
Allocating
memory, 3-58, 3-65
space, 3-23
/ARSIZE
LINK switch, 3-6
/BACKSPACE
LINK switch, 3-7
Blocks
REL, A-I
Calls to overlay handler, 5-15
.CCL files, 3-2
Clearing
DECtape, 3-80
module requests, 3-39
Closing overlay links, 3-27
CLROV., 5-16
CLROVL, 5-16
Code
relocatable, 1-2
Command
comments, 3-1
indirect files, 3-2
str ing, 3-2
/COMMON
LINK switch, 3-8
CONCATENATE
PSECTs attribute, 6-3
Conserving memory space, 3-41
Constructing overlays, 3-50
/CONTENTS
LINK switch, 3-9
Continuing commands, 3-1
/CORE
LINK switch, 3-10
CORE (see memory), 3-21
Core image, 1-2
/COUNTERS switch, 3-11
/CPU
LINK switch, 3-12.1
CPU type
specifying, 3-12.1
Creating
EXE files, 3-59
sharable save files, 3-66
Data word, A-I
/DDEBUG
LINK switch, 3-13
DDT, 2-1
/DEBUG
LINK switch, 3-14
DEBUG system command, 2-1
Debuggers
loading, 3-14, 3-72
specifying, 3-13

Debtigging overlayed programs,
5-14
/DEFAULT
LINK switch, 3-15
Default file specifications, 3-15
/DEFINE
LINK switch, 3-16
Diagram
tree, 3-52
Displaying
relocation counters, 3-11
Ending loading, 3-22
/ENTRY
LINK switch, 3-17
Entry name symbols
·deleting, 3-38
Entry points
overlay handler, 5-15
Entry vector section
sharable save file, 4-4
/ERRORLEVEL
LINK switch, 3-18
/ESTIMATE
SCAN switch, 3-3
/EXCLUDE
LINK switch, 3-19
/EXECUTE
LINK switch, 3-20
EXECUTE system command, 2-1
Execution
starting, 3-20
/EXIT
SCAN switch, 3-3
Extended addressing, 1-3
EXTTAB table, 5-36
File
core image, 4-1
executable, 1-2
library, 1-2
log, 1-3, 4-5
map, 1-3, 4-5
overlay format, 5-30
REL, 1-1
sharable save, 1-2, 3-59
symbol, 1-3, 3-69, 4-5
FORTRAN
COMMON storage, 3-8
/FRECOR
LINK switch, 3-21
FUNCT. subroutine, 5-11, 5-24
GETOV., 5-17
GETOVL, 5-17
Global switches, 3-5
Global symbols, 1-2
suppressing, 3-68

Index-l

April 1986

/GO
LINK switch, 3-22
/HASHSIZE
LINK switch, 3-23
Header word, A-I
/HELP
SCAN switch, 3-3
IDXBFR, 5-14
INBFR, 5-15
/INCLUDE
LINK switch, 3-24
Including local symbols, 3-28
INIOV., 5-17
INIOVL, 5-17
INTTAB table, 5-37
Job data area
see JOBDAT
JOBDAT, C-l
Libraries
searching, 3-60, 3-71, 3-76,
3-81
Library file, 1-2, 3-81
/LIMIT
LINK switch, 3-25, 6-1
Limits
symbol table, 3-75
/LINK
LINK switch, 3-27
LINK
command, 3-1
messages, 4-7, B-1
number table format, 5-32
overlay switches, 5-2
starting, 3-1
switch, 3-4
LOAD system command, 2-1
Loading
FORTRAN COMMONs into PSECTs,
3-54
PSECTs, 6-1
two-segment code using PSECTs,
3-54.1
Local switches, 3-5
/LOCALS
LINK switch, 3-28
/LOG
LINK switch, 3-29
Log file, 1-3, 4-5
overlay, 5-18
specifying, 3-29
/LOGLEVEL
LINK switch, 3-30
LOGOV., 5-18
LOGOVL, 5-18
Long count, A-I
Magtape operations, 3-35
Maintaining
free memory, 3-21

/MAP
LINK switch, 3-31
Map file, 1-3, 4-5
/MAXCORE
LINK switch, 3-32
/MAXNODE
LINK switch, 3-33
MBZ, A-I
Memory size
specifying, 3-5
/MESSAGE
SCAN switch, 3-3
Messages
controlling, 3-78
levels, 4-7
LINK, 4-7, B-1
overlay handler, 5-21
severity, 4-7, B-2
suppressing, 3-18, 3-30
/MISSING
LINK switch, 3-34
Modules
loading, 3-19, 3-55
specifying, 3-24
/MTAPE
LINK swi tch, 3-35'
Naming overlay links, 3-27
/NEWPAGE
LINK switch, 3-36
/NODE
LINK switch, 3-37
/NOENTRY
LINK switch, 3-38
/NOINCLUDE
LINK switch, 3-39
/NOINITIAL
LINK switch, 3-40
/NOLOCAL
LINK switch, 3-41
Non-writable links
declaring, 5-16
/NOREQUEST
LINK switch, 3-42
/NOSEARCH
LINK switch, 3-43
/NOSTART
LINK switch, 3-44
/NOSYMBOL
LINK switch, 3-45
/NOSYSLIB
LINK switch, 3-46
/NOUSERLIB
LINK switch, 3-47
Number of overlay links
specifying, 3-33
Object modules, 1-1
Object-time systems
loading, 3-49
Obtaining information, 3-34,
3-54.2, 3-73, 3-77

Index-2

April 1986

/REDIRECT switch, 3-54.1
REL blocks, A-l
REL file, 1-1
Relocatable
code, 1-2
overlays, 5-11
Relocation counters
displaying, 3-11
setting, 3-36, 3-62
REMOV., 5-19
Removing links, 5-19
REMOVL, 5-19
/REQUEST
LINK switch, 3-54.2
/REQUIRE
LINK switch, 3-55
Resetting symbol types, 3-9
Restrictions
Overlays, 5-12
/REWIND
LINK switch, 3-56
Rewinding magtape, 3-56
Root link, 5-1
/RUN
SCAN switch, 3-4
/RUNAME
LINK switch, 3-57
/RUNCOR
LINK switch, 3-58
Running links, 5-19
RUNOV., 5-19
RUNOVL, 5-19

/ONLY
LINK switch, 3-48
/OPTION
SCAN switch, 3-4
Origin
PSECTs, 6-1
/OTSEGMENT
LINK switch, 3-49
Overflow to disk, 3-32
OVERLAID
PSECTs attribute, 6-3
/OVERLAY
LINK switch, 3-50
Overlay handler, 5-14
Overlay link, 3-37
closing, 3-27
deleting, 3-42
format, 5-33
name table format, 5-32
naming, 3-27
overlay code, 5-35
paths, 5-1
preamble, 5-34
Overlaying links, 5-15
Overlays, 1-3
constructing, 3-50
program size, 5-14
relocatable, 5-11
restrictions, 5-12
writable, 5-10
/PATCHSIZE
LINK switch, 3-51
Permanent switches, 3-5
/PLOT
LINK switch, 3-52
Plot file
specifying, 3-53
/PLTTYP
LINK switch, 3-53
Predecessor overlay links, 5-1
Preventing JOBDAT loading, 3-40
Printing entry name symbols, 3-17
Program
controlling termination, 3-63
executable, 4-1
/PROTECTION
SCAN switch, 3-4
/PSCOMMON LINK switch, 3-54
PSECTs, 6-1
attributes, 6-3
CONCATENATE, 6-3
OVERLAID, 6-3
loading, 6-1
loading two-segment code into,
3-54.1
origin, 6-1
preventing unintented overlaps,
6-1
specifying upper bounds, 3-25,
6-1
PSECTs origin, 3-62

/SAVE
LINK switch, 3-59
Save file
format, 4-2
SAVOV., 5-20
SAVOVL, 5-20
SCAN switches, 3-3
/SEARCH
LINK switch, 3-60
Searching libraries, 3-60, 3-71,
3-76, 3-81
/SEGMENT
LINK switch, 3-61
Segments
loading, 3-48
specifying, 3-61
/SET
LINK switch, 3-62, 6-1
/SEVERITY
LINK switch, 3-63
Severity codes of messages, B-2
Sharable save file, 1-2, 3-59
entry vector section, 4-4
Short count, A-l
/SKIP
LINK switch, 3-64
Skipping magtape, 3-64
/SPACE
LINK switch, 3-65

Index-3

April 1986

Specifying
job names, 3-57
memory size, 3-1~
start addresses, 3-67
/SSAVE
LINK switch, 3-66
/START
LINK switch, 3-67
Structure
overlay, 5-1
tree, 5-1
Successor overlay links, 5-1
/SUPPRESS
LINK switch, 3-68
Switch
global, 3-5
local, 3-5
permanent, 3-5
temporary, 3-5
values, 3-5
/SYFILE
LINK switch, 3-69
Symbol
defining, 3-16
Symbol file, 1-3, 4-5
Symbol table vector, 4-5
/SYMSEG
LINK switch, 3-7~
/SYSLIB
LINK switch, 3-71
System command switches, 2-2
Table
relocation, 5-38

Table (Cont. )
symbol, 3-7~
Temporary switches, 3-5
/TEST
LINK switch, 3-72
/TMPFIL
SCAN switch, 3-4
/UNDEFINED
LINK switch, 3-73
/UNLOAD
LINK switch, 3-74
Unloading magtape, 3-74
Uppar bounds for PSECTs, 6-1
specifying, 3-25
/UPTO
LINK switch, 3-75
/USERLIB
LINK switch, 3-76
/VALUE
LINK switch, 3-77
/VERBOSITY
LINK .swi tch, 3-78
/VERSIO~

LINK switch, 3-79
Virtual memory, 1-1
Word relocation, A-I
Writable links
declaring, 5-2~
Writable overlays, 5-l~
/ZERO
LINK switch,

Index-4

3-8~

April 1986

TOPS-10
LINK Reference Manual
AA-0988D-TB

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UPDATE NOTICE
TOPS-10
LINK Reference Manual
AD-0988D-T1

January 1985

Insert this Update Notice in the TOPS-10 LINK Reference
Manual to maintain an up-to-date record of changes to the
manual.
The instructions for inserting this update start on the next page.

~DmDD~D

wore

INSTRUCTIONS
AD-0988D-T1
The following list of page numbers specifies which pages are to be placed in the TOPS-10 LINK
Reference Manual as replacements for, or additions to, current pages.
[Title page
Copyright page

[3-59
3-60

[5-21
5-22

[Entire
Contents

[3-67
3-68

[Entire
Chapter 6

[3-49
3-50

[5-9
5-10

[Entire
Appendix A
[Entire
Index

KEEP THIS UPDATE NOTICE IN YOUR MANUAL TO MAINTAIN AN UP-TO-DATE
RECORD OF CHANGES.
TYPE AND IDENTIFICATION OF DOCUMENTATION CHANGES.
Five types of changes are used to update documents contained in the TOPS-10 software manuals.
Change symbols and notations are used to specify where, when, and why alterations were made to
each update page. The five types of update changes and the manner in which each is identified are
described in the following table.

The Following Symbols and/or Notations

Identify the Following Types of Update Changes

1. Change bar in outside margin; version number and change date printed at bottom of
page.

1. Changes were required by a new version of
the software being described.

2. Change bar in outside margin; change date
printed at bottom of page.

3. Change date printed at bottom of page.

3. Changes were made for editorial purposes
but use of the software is not affected.

4. Bullet (e) in outside margin; version number
and change date printed at bottom of page.

Data was deleted to comply with a new version of the software being described.

Data was deleted to either clarify or correct
the eXisting material.

Bullet (e) in outside margin; change date
printed at bottom of page.

Changes were required to either clarify or
correct the existing material.

UPDATE NOTICE

TOPS-10
LINK Reference Manual

AO-09880-T2
April 1986
Insert this Update Notice in the TOPS-10 LINK Reference
Manual to maintain an up-to-date record of changes
to the manual.
Changed Information
The changed pages contained in this update package reflect
the changes to LlNK-10 from Version 5.1 to Version 6.0.
The instructions for inserting this update start on the next page.

~D~D[J~D

wore

INSTRUCTIONS

AO-09880-T2
The following list of page numbers specifies which pages are to be placed in the TOPS-10
LINK Reference Manual as replacements for, or additions to, current pages.
Title Page
Copyright Page

3-61
3-62

A-40.1
A-40.6

Entire
Contents

3-67
3-70

A-45
A-69

1-3
1-4

3-75
3-76

Entire
Appendix B

3-7
3-12.2

Entire
Chapter 4

Entire
Appendix C

3-21
3-22

Entire
Chapter 6

Entire
Index

3-53
3-54.2

A-13
A-14

KEEP THIS UPDATE NOTICE IN YOUR MANUAL TO MAINTAIN AN
UP-TO-DATE RECORD OF CHANGES.
TYPE AND IDENTIFICATION OF DOCUMENTATION CHANGES.
Five types of changes are used to update documents contained in the TOPS-1 0 software
manuals. Change symbols and notations are used to specify where, when, and why
alterations were made to each update page. The five types of update changes and the manner
in which each is identified are described in the following table.
The Following Symbols and/or Notations

Identify the Following Types of Update Changes

Change bar in outside margin; version
number and change date printed
at bottom of page.

Changes were required by a new version
of the software being described.

Change bar in outside margin; change date
printed at bottom of page.

Changes were required to either clarify or
correct the existing material.

Change date printed at bottom of page.

Changes were made for editorial purposes
but use of the software is not affected.

Bullet (e) in outside margin; version number
and change date printed at bottom of page.

Data was deleted to comply with a new version of the software being described.

Bullet (e) in outside margin; change date
printed at bottom of page.

Data was deleted to either clarify or correct
the existing material.

April 1986