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Document:	IAS/RSX-11 ODT Reference Manual
Order Number:	AA-M507A-TC
Revision:	0
Pages:	70
Original Filename:	http://bitsavers.org/pdf/dec/pdp11/rsx11m_s/RSX11M_V4.1_Apr83/4_ProgramDevelopment/AA-M507A-TC_odt_198201.pdf

OCR Text

IAS/RSX-11
ODT Reference Manual
Order No. AA-M507 A-TC

RSX-11 M Version 4.0
RSX-11 M-PLUS Version 2.0
IAS Version 3.1

digital equipment corporation · maynard, massachusetts

First Printing, December 1975
Revised, May 1977
Revised, January 1982
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.

@ 1975, 1977, All1978,Rights
1982 by Digital Equipment Corporation
Reserved.
Printed in U.S.A.

The postpaid READER'S COMMENTS form on the last page of this document
requests the user's critical evaluation to assist in preparing future
documentation.
The following are trademarks of Digital Equipment Corporation:
DEC
DECnet
DECsystem-lo
DECSYSTEM-20
DEC US
DECwriter
DIBOL

EduSystem
IAS

MASSBUS
PDP
PDT
RSTS

RSX
UNIBUS
VAX
VMS
VT

ZK20~2

CONTENTS

Page
PREFACE

vii

SUMMARY OF TECHNICAL CHANGES

CHAPTER 1

INTRODUCTION TO ODT

1.1
OVERVIEW OF ODT
• • • • • • • • •
1. 2
LINKING ODT WITH A USER PROGRAM
1. 2 .1
Linking ODT from MCR • • • • • • • •
1. 2. 2
Linking ODT from DCL • • • • •
1. 2. 3
Linking ODT Using IAS PDS
• • • • • • • • •
1. 2. 4
Linking to Enable RSX-llM-PLUS Features
1.2.4.1
Enabling Instruction and Data Space
1.2.4.2
1. 3

1.4
1.5
1. 5 .1
1. 5. 2
CHAPTER 2

2.1
2.2
2.2.1
2.'2.2
2.3
CHAPTER 3

3.1
3 .1.1
3 .1. 2
3.2
3" 3

3.4
3.5
CHAPTER 4

4.1
4.2
4.3
4.3.1
4.3.2
4.3.3

• • 1-1
• • 1-2

• • 1-2
1-3
• • 1-3
• 1-3

(RSX-llM-PLUS only) • • • • • •
• •
Enabling Supervisor-Mode Library Debugging
(RSX-llM-PLUS only)
• • • • • • • • • • •
INVOKING ODT • • • • • •
• • • • • • • • •
RETURNING CONTROL TO THE HOST SYSTEM • . • • • • •
INTERRUPTING A DEBUGGING SESSION • • • • • • • • •
Resuming a Debugging Session (RSX-llM-PLUS)
••
Resuming a Debugging Session (!AS) • • • • • • •

1-3
1-4

1-4
1-4
1-5
1-5
1-5

ODT CHARACTERS AND SYMBOLS
VARIABLES USED IN COMMAND DESCRIPTIONS •
• • • 2-1
• • • • 2-2
ADDRESS EXPRESSION FORMATS • • • • •
Absolute and Relative Addressing • • • • •. • • • 2-2
Forming Expressions
••••
• 2-3
OPERATOR AND COMMAND SUMMARY •
2-4
CONTROLLING PROGRAM EXECUTION
SETTING AND REMOVING BREAKPOINTS •
Setting Breakpoints
• • • •
Removing Breakpoints • • • • •
BEGINNING PROGRAM EXECUTION
• • •
CONTINUING PROGRAM EXECUTION
USING THE BREAKPOINT PROCEED COUNT
STEPPING THROUGH THE PROGRAM

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

•
•
•
•

3-1
3-1
3-2
3-2

• • • • • • • • 3-4

• • • • • 3-4

DISPLAYING AND ALTERING THE CONTENTS OF LOCATIONS
ALTERING THE CONTENTS OF A LOCATION
• • • •
• 4-1
CLOSING A LOCATION • • • • • • •
• • 4-2
OPENING WORD AND BYTE LOCATIONS
• • • • • • 4-2
The a/ and a\ Commands • • • •
• • • • • • • 4-2
The I and \ Commands • • • • •
• • 4-3
Moving Between Word and Byte Modes •
4-3
iii

CONTENTS
Page
4.4
4.5
4. 'i
4.7
4.8
4.9
4.10
4.10.l
4.10.2
CHAPTER 5

OPENING THE NEXT SEQUENTIAL LOCATION •
• 4-4
4 ..... 4
OPENING THE PRECEDING LOCATION •
OPENING ABSOLUTE LOCATIONS • •
• • • • • • • 4-4
OPENING PC-RELATIVE LOCATIONS
• • 4-5
OPENING RELATIVE BRANCH OFFSET LOCATIONS •
• 4-5
RETURNING FROM A CALCULATED LOCATION •
• • • 4-6
USING DIFFERENT OUTPUT MODES • • • • •
. 4-6
ASCII Mode • • •
• 4-6
Radix-50 Mode
4-7
USING REGISTERS

5.1
GENERAL REGISTERS
• • • • • • • • • • • •
• 5-1
Examining and Setting General Registers
• 5-1
5 .1.1
5 .1. 2
Contents of General Registers
• • • • •
5-2
5.2
ODT INTERNAL REGISTERS • • • • • • •
• • • 5-2
5.2.l
Relocation Registers • • • • • • •
• • • • 5-6
Setting Relocation Registers •
• 5-6
5.2.1.1
Clearing Relocation Registers
• 5-6
5.2.1.2
5.2.2
The Reentry Vector Register
5-7
CHAPTER 6
6.1
6 .1.1
6 .1. 2
6 .1. 3
6 .. 1..4
6.2
6.2.1
6.2.2
15:2:3

6.3
6.4
n.4.1
6.4.2
CHAPTER 7
7.1
7.2
7.3
7.3.1
7.3.2
7.3.3
7.3.4
7.3.5
CHAPTER 8

MEMORY OPERATIONS
REGISTERS USED IN MEMORY OPERATIONS
• •
Search Limit Registers
•
Search Mask Register •
• • • •
Search Argument Register • • • • • •
• •
Device Control LUN Registers
••
SEARCHING MEMORY • • • • • • • •
Searching for a Word or Byte
•.••••••
Searching for Inequality of a Word or Byte • • •
Searching for n Reference • • • •
FILLING MEMORY • •
• • • • • • • •
LI STING MEMORY •
• • • •
• •
Command Format
• • • • • • • • • • • • • •
Listing Format •
. • • •
• • • •
•

6-1
6-1
6-2
6-2
6-2
6-3
6-3
6-3
6-3
6-4
6-4
6-4
~-5

PERFORMING CALCULATIONS
CALCULATING RELOCATABLE ADDRESSES
•
CALCULATING OFFSETS
• • • • •
EVALUATING EXPRESSIONS • • • •
Equal Sign Operator
Current Location Indicator •
. • •
Constant Register Indicator
Quantity Register Indicator
Radix-50 Evaluation
••••••• • • •

• • • • 7-1
• 7-1
• 7-2
7-2
•
• 7-3
• • • • 7-3
• • 7-3
• • • • 7-4

ADDITIONAL DEBUGGING AIDS

8.1
ACCESSING OTHER DEBUGGING AIDS
8-1
8 .1.1
MCR Command Line • •
• • • • •
• 8-1
8. 1. 2
DCL Command Line • • • • • •
• • • •
• 8-1
8 .1. 3
IAS PDS Command Line • • • •
• 8-2
8.2
THE TRACE DEBUGGING PROGRAM
. • • • • • • •
• 8-2
8.2.l
The Trace Listing
••••••••
• • 8-2
8.2.2
Bias Values and Ranges • • •
• 8-3
8.2.2.l
Specifying a Bias Value
• • • 8-3
8.2.2.2
Specifying Ranges to be Traced
• 8-3

CONTENTS
Page
APPENDIX A
A. l
A.2

APPENDIX B

ERROR DETECTION
INPUT ERRORS • •
• • • •
TASK IMAGE ERROR CODES •

• A-1
• A-2

PROCESSOR STATUS WORD

INDEX

EXAMPLES
EXAMPLE 6-1
8-1

ODT Listing Format •
Sample Trace Output

• • • • • • • • •
• 6-5
• • • • •
• • • • • 8-3

FIGURES
FIGURE

B-1

Format of the Processor Status Word

• • • • • • • B-1

TABLES
TABLE

2-1
2-2
2-3
5-1
5-2
7-1

Variables Used in ODT Command Descriptions • • • •
Forms of Address Expressions • • • • •
• • • •
ODT Operators and Commands • • • • • • • • •
•
ODT Single Registers • • • • • • • • • • • •
•
ODT Register Sets
••••••••••••••
Numeric Equivalents of Radix-SO Characters • • • •

2-1
2-4
2-4
5-3
5-4
7-4

PREFACE

MANUAL OBJECTIVES
This manual describes the On-Line Debugging Tool, ODT-11,
used to
debug user task images on RSXll-M, RSX-llM-PLUS, and IAS systems.
It
provides reference information on all ODT commands, plus information
on how to use the commands to debug user task images.

INTENDED AUDIENCE
This manual is intended for all systems and applications programmers
who develop task images under the RSX-llM, RSX-llM-PLUS, or IAS
ope~ating systems.
Readers should understand the user interface of
the operating system that they are using.
RSX-llM and RSX-llM-PLUS
users should be familiar with the contents of the RSX-llM/M-PLUS ·Guide
to Program Development before reading this manual.
~~·-

STRUCTURE OF THIS DOCUMENT
This manual is divided into eight
follows:

chapters

and

two

appendixes,

Chapter 1, Introduction to ODT, gives an overview of ODT.
It then
explains how to link the debugger into a user task image and how to
begin and end a debugging session.
Chapter 2, ODT Characters and Symbols, explains the special symbols
used in ODT and includes a reference table of all ODT commands, in
alphabetical order. Readers who are approaching ODT for the first
time should read Chapters 3 through 7 for explanations of the commands
before studying the table of commands in detail.
Experienced ODT
users can use Chapter 2 by itself for quick reference.
Chapter 3, Controlling Program Execution, describes the command used
to begin program execution, to stop execution at breakpoints, and to
continue execution after breakpoints.
It also explains how to execute
a program one or more instructions at a time.
Chapter 4, Displaying and Altering the Contents of Locations, explains
how to open and close task locations, how to change the contents of
locations, and how to display the contents of locations in different
modes.
Chapter 5, Using Registers, describes all of the registers used by
ODT.
It includes reference tables as well as explanations of how
registers are set and cleared.
Experienced ODT users may wish to
consult the tables in this chapter, as well as those in Chapter 2, for
quick reference regarding specific registers.

vii

PREFACE
Chapter 6, Memory Operations, describes ODT's memory search, fill, and
list capabilities.
Chapter 7, Performing Calculations,
perform arithmetic calculations.

describes

how

use

ODT

Chapter 8, Additional Debugging Aids, explains how to link debuggers
other than ODT into a
user task image.
It describes the Trace
program, a debugging aid that can be used in conjunction with ODT.
Appendix A, Error Detection, describes how ODT responds to errors in
user
input or program logic.
It lists all ODT error message codes in
alphabetical order.
Appendix B, Processor Status Word, shows the format
summarizes the functions of its bits.

the

PSW

and

ASSOCIATED DOCUMENTS
The documentation directory of the host operating system
other manuals that will be of interest to ODT users.

describes

CONVENTIONS USED IN THIS DOCUMENT
Throughout this book symbols and other notation conventions are used
to
represent keyboard characters, to convey textual information, and
to aid the reader's understanding of material.
These symbols and
conventions are explained below.
Convention

Meaning
A symbol with a 1- to 3-character abbreviation,
such as
@
or
filD , indicates that you press a
key on the terminal.
This phrase indicates that you press the key
labeled CTRL while simultaneously pressing another
key, such as C or Y.
In examples,
this control
key sequence is shown as AX (for example, AC or
AY), because that is how the system displays it on
your terminal.

red ink

shading

User input appears in red
ink in the examples
throughout this book.
ODT responses appear in
black ink.

G:~~Y: < s~adfri<J d.e·no~e$ : inform~•ti:()ri ... ~p'~cif£ici·.
RS)<::~l·U-1-J?I.US.~ ·

viii

··. to·

SUMMARY OF TECHNICAL CHANGES

This manual describes four new ODT commands for
systems:

use

Accesses data space

Accesses instruction space

Sets the current mode of ODT to user mode

Sets the current mode of ODT to supervisor mode

RSX-llM-PLUS

text and
This manual also corrects small technical errors in
examples of the previous version.
It represents a significant
information
more
reorganization of material, intended to make
available to readers.

CHAPTER 1
INTRODUCTION TO ODT

ODT, or On-line Debugging Tool,
images. You can use ODT to:

utility

for

debugging

•

Control program execution

•

Display the contents of locations or registers

•

Alter the contents of locations or registers

•

Search and fill memory

•

Perform calculations

task

ODT commands consist of one character; some commands take a numeric
or alphabetic argument.
All ODT commands, and the symbols that are
used in them, are listed in Chapter 2.
Chapters 3 through 7 describe
how you use the commands.
This chapter
initiated.

1.1

introduces

ODT

and

describes

how

the

debugger

OVERVIEW OF ODT

ODT is special code that you link into your task image to help you
debug your program.
When you run a task into which ODT has been
linked,
the debugger receives control automatically
upon
task
initiation.
Then, through ODT, you can execute your task gradually,
setting breakpoints at selected locations or stepping through the
program one instruction at a time.
Chapter 3 describes ODT commands
for controlling program execution.
You can examine any location in your program -- instruction or data,
word or byte -- by "opening" the location with ODT.
While the
location is open, you can immediately change the contents.
You can
proceed forwards or backwards to examine and modify other locations.
Thus, you can test any number of modifications without rebuilding your
task.
Chapter 4 describes ODT commands for examining and altering
locations and for moving from one location to another.
ODT operates through the use of a number of registers, all of which
you can set and reset.
Some of these registers are used to store
information about your program while ODT has control.
Eight registers
can be set to the locations of breakpoints.
Eight can be set to
relocation biases -- the absolute base addresses of relocated object
modules.
You can use other registers to store values that you may
want to use repeatedly during your debugging session.
Chapter 5
describes the ODT registers.

1-1

INTRODUCTION TO ODT
You can use ODT to search for bit patterns in memory, to fill blocks
of memory with a value, or to list blocks of memory on an output
device. Chapter 6 describes these operations.
During a debugging session, you can perform a variety of calculations:
determining
offsets,
evaluating
arithmetic
expressions,
and
constructing Radix-50 words.
These calculations are described in
Chapter 7.

1.2

LINKING ODT WITH A USER PROGRAM

09rr, i~ .woxiq~cj
·....·.. ·······.·T.···.·.·
..

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.. ·.·. .

op~."'.····X<>ll.r:' ~x~~.~l!l as ·.·.·. f=l.....n.1··· ·.·.n··.· ··s't.r·u·;.;.+.1··o·n
· .~· .l:>. .j.·.~·.·~···.~·. ·.•·. m.·...· .·.·a··
o· ·.•:.d.11.1 ..~.·.· · '·. . . . . ·. .·.. L..~.·.·. . =. [.l·.··.'•·.+.1. . I)····.'r,. ~·.·..P.~.·.J.·.·. .•~
n··
d. at.· a· ··s· na· r.e· . ·&;.,.at· u··r·e·'·s· .,.
;~><·>>\····''.?'1.·······
.
.
;.··c.•
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·.··.:···.····•·•.·:>\ . . . . .~• ·.·•':•·rx~~···.·. ·····.}··•··;·.·.·.···•·······>··.···
J?LUS···
.:·•. ·.<.;>'p:j.e~.t. . .-•.'ftlod.µ:Le.
.• I;;l.],;OQ~r.p·~.QJ:J;'.J,•."'

•..n·. .·.·.·•·.·.·.··.·.·..·.·.. . . .

··.·.o.

·.·.·.·.·.f.·.·.. .••..·•.•.

·a.··.·•
.. ·.o·

.·. ·.·•

. .

.· ·

a·· ..

·of· RSX~.
To use ODT,
link the appropriate object module with the
object module(s) of your program. When the resulting task image is
run, ODT is invoked and initiated automatically.
vi

..,..

.Ji·

If the task image is overlaid, ODT is linked into the root segment
that the debugger will always be available.

The following sections describe how to link ODT into a task image in
different environments.
Section 1.2.1 describes how to link ODT if
your command line interpreter is MCR. Section 1.2.2 describes how to
link ODT using the DCL command line interpreter. Section 1.2.3
describes how to use the !AS Program Development System (PDS) to link
ODT into your task image. Section 1.2.4 describes how to enable the
I- and D-space and supervisor-mode features of ODT used under
RSX-llM-PLUS.
The information in subsequent sections on initiating
applies equally to all environments, except as noted.

1.2.1

and

using

ODT

Linking ODT from MCR

To link ODT with your program when your command line interpreter is
the Monitor Console Routine (MCR), you first invoke the Task Builder
by typing TKB in response to the MCR prompt. The Task Builder replies
with its own prompt, TKB>. In response to this prompt, enter a Task
Builder command specifying the name of the file(s)
to be linked.
Include the /DA switch, which indicates that a debugger (in this case
ODT, the default) should be linked into the image.
The following
example shows the resulting command line:
TKB>MYTASK/DA=MYFILE1,MYFILE2
The Task Builder accesses the file DDT.OBJ in UFO [1,1] on the library
device and links it with the files MYFILEl.OBJ and MYFILE2.0BJ into
the task MYTASK.
Using ODT requires that you consult an up-to-date map of your task.
Therefore, you should in most cases request a new map when you build
the task, as in the following command line:
TKB>MYTASK/DA,MYTASK/CR/-SP=MYFILE1,MYFILE2
For more information on using the Task Builder,
consult
the
RSX-llM/M-Plus Task Builder Manual or the IAS Task Builder Reference
Manual, as appropriate for your system.
~- -~-

1-2

INTRODUCTION TO ODT
1.2.2

Linking ODT from DCL

To link ODT with your program(s) when your command line interpreter is
the DIGITAL Command Language (DCL), use the /DEBUG qualifier with the
LINK command. To obtain a current map of the image file produced, you
should also include the /MAP qualifier. The following example shows
the resulting command line:
>LINK/MAP/DEBUG/TASK:MYTASK MYFILE1,MYFILE2
Object modules MYFILEl.OBJ and MYFILE2.0BJ are linked with object
module DDT.OBJ in UFD [1,1] on the library device. The resulting task
image is named MYTASK.TSK.
For further information on
Command Language Manual.

1.2.3

DCL,

using

consult

the

RSX-llM/M-PLUS

Linking ODT Using !AS PDS

To link your program(s) with the !AS Program Development System, enter
the LINK command with the /DEBUG switch in response to the PDS prompt.
To obtain a map of the image file produced, include the /MAP switch as
well. The following example shows the resulting command line:
PDS> LINK/MAP/DEBUG MYFILE
This command links the object module MYFILE.OBJ with the object module
ODT.OBJ from LB:[l,l] to produce the task image MYFILE.TSK.
For more information on linking
Builder Reference Manual.

under

IAS,

consult

the

IAS

You c.an add other switches to the command lJne as desired.
the RSX-HM/M-PLUS
Builder Manual for information on TKS

lines.

1-3

Task

INTRODUCTION TO ODT

1.3

INVOKING ODT

ODT is invoked automatically when you run a task image into which ODT
has been linked, as described in the previous sections. Regardless of
what operating system or CLI you use, enter the RUN command,
specifying the name of the task image file.
ODT responds with a message indicating that it has been invoked and
identifying the task image that it controls. On the next line, ODT
displays its prompt, an underscore( ) , indicating that it is ready to
accept commands.
'T''ho
........ "°'

Fr.11r.•·•;,...,..

~"°'..&...&..Vn•'&":JI

ov,,....,n1o
'-.1\.\.A.&Ut'..L.'-

/.,.,.;
.... ,..
\ U....,;J•.&l.~

Mf"O\

l"J.'-'I."\.}

shows

how

CDT

HIYA.TSK is run:
>RUN HIYA
ODT:TT15
In response to the ODT prompt, you can enter any ODT command.
ODT
commands are immediate-action commands; that is, ODT responds to the
commands as soon as they are typed, without waiting for a line
terminator.
Therefore, commands cannot be corrected once they have
been typed. You can, however, erase an incorrectly typed command
argument by typing an illegal character or command (such as 8 or 9),
or by typing
~
or
00,l
In response, ODT discards your input
line, displays a question mark (?), and prompts for another command.
Error detection is described in greater detail in Appendix A.

1.4

RETURNING CONTROL TO THE HOST SYSTEM

To return control from ODT to the host operating system, type X in
response to the ODT prompt.
This command causes execution of the
system Task Exit directive, which terminates task execution.

1-4

INTRODUCTION TO ODT
1.5

INTERRUPTING A DEBUGGING SESSION

When you run a task linked with ODT, you can return to the command
line interpreter prompt at any time by typing
~
Your task is
still active. To stop execution of the task, enter the ABORT command
in response to the MCR or DCL prompt. You cannot resume the aborted
debugging session; you can only run your program again.
On RSX-llM-PLUS and IAS systems, you can interrupt task execution
without aborting your task and then continue debugging. After typing
~
, use the commands described in the following sections, as
appropriate for your system.

1.5.2

Resuming a Debugging Session (IAS)

On an IAS time-sharing system using the PDS command line interpreter,
you can use the CONTINUE/DEBUG command to interrupt task execution and
return to the ODT prompt. ODT responds with a TE error message,
showing the current value of the program counter as the location where
the error occurred.

1-5

INTRODUCTION TO ODT
The following example shows how the CONTINUE/DEBUG command is used:
PDS> RUN MYFILE
ODT:TTS
G

PDS> CONTINUE/DEBUG
TE:004020
Note that this command can be used only on a time-sharing system, not
on an IAS multiuser system.
For further information, consult the IAS
PDS User's Guide.

1-6

CHAPTER 2
ODT CHARACTERS AND SYMBOLS

This chapter presents all of the ODT operators and commands and
explains the meanings of DDT-specific symbols used in this book.
(Symbols common to the document set are presented in the Preface.)

2.1

VARIABLES USED IN COMMAND DESCRIPTIONS

Table 2-3 and the command descriptions in Chapters

lowercase

alphabetic

variables

arguments specified in commands.
2-1.

through

use

represent numaric and alphabetic

These symbols are explained in Table

Table 2-1
Variables Used in ODT Command Descriptions
Variable

Meaning

An address expression representing the address of a
task image location. The various forms in which an
address expression can be specified are explained in
Section 2.2.

An octal value up to 6 digits long with a maximum
value of 177777(octal), or an expression representing
such a value. An expression may include arithmetic
operators or indicators, as described in Section
2.2.2.
If more than 6 digits are specified, ODT
truncates to the low-order 16 bits.
If the octal
value is preceded by a minus sign, ODT takes the
two's complement of the value.

An octal value six digits long, used to
search mask.

An octal integer in the range O through 7.

An alphabetic character.
alphabetic characters is
the variable x is used.

2-1

represent

A list
of
permitted
given in the tables where

ODT CHARACTERS AND SYMBOLS
2.2

ADDRESS EXPRESSION FORMATS

An address expression, represented throughout this manual by the
lowercase letter a, is an expression interpreted by ODT as a 16-bit
{6-digit octal) value. You use an address expression to refer to a
location in your task.
You can specify an address expression in either absolute or relative
{relocatable) form, as described in Section 2.2.1. You can include in
the address expression various operators and symbols, as described in
Section 2.2.2.

2.2.l

Absolute and Relative Addressing

Each location has an absolute address assigned to it when the task is
built.
You can refer to the location using this ~-digit octal value.
However, when the task is built again, with modules added or changed,
this value may not refer to the same location. Therefore, it is often
more convenient to refer to locations using relative {relocatable)
addressing, which is less likely to be affected by subsequent task
builds.
When you use relative addressing, you refer to a location not by its
absolute value but by its position relative to a movable point.
Usually, this movable point is the base {starting) address of the
module to which the location belongs, because the distance between the
base address and the addresses of locations within the module is
easily determined from a task map or listing and is not likely to
change without your knowledge. The movable point can, however, be any
point that is convenient for debugging.
To use this form of addressing, you must first establish a simple
means of referring to movable points through the use of ODT's
relocation registers $RO through $R7, Each time you run a task built
with ODT, consult a task map to determine the absolute addresses of
convenient movable points.
The map's memory allocation synopsis
contains the base addresses of all the modules in the task. Follow
the procedure described in Section 5.2.1.1 to set ODT's eight
relocation registers to absolute addresses.
Once a relocation register is set, you can use the number
register, 0 through 7, in forming relative addresses.

that

through

A relative address has the following form:
n,k
n

The number of a relocation
representing $RO through $R7.

A required separator
relative address.

the

parts

(comma)

2-2

between

two

the

ODT CHARACTERS AND SYMBOLS
k

The relative location, the distance of the desired
location from the value contained in register $Rn.
Usually, this is the location's position within the
module whose base address is the value of the register.
Thus, relative address 0,100 refers to location 100 within the module
whose base address is stored in ODT's relocation register $RO.
Relative address 5,300 refers to location 300 within the module whose
base address is stored in relocation register $RS.
A general term for the value stored in a relocation register is 11 bias
value":
a quantity equal to the distance (bias) between a relative
location and its absolute address. A general term for the second part
of a relative address is "offset":
the distance of a relative
location from the closest value (less than that location) stored in a
relocation register. These terms are used throughout this manual.

2.2.2

Forming Expressions

An expression is a string of numbers, symbols, and operators that is
interpreted as a number.
For example, 3+6 is an expression; ODT
would interpret it as the octal value 11.
You can use an expression to represent an absolute address, a register
containing a bias value, or an offset, as described in Section 2.2.1.
An expression used in an ODT session can contain any of the
elements:

following

•

Octal numbers. ODT will not accept input containing an 8
9;
instead, it displays a question mark and a new prompt.

•

The arithmetic operators plus sign (+) or space, indicating
that values should be added, or minus sign (-), indicating
that the value that follows it should be subtracted from the
value that precedes it.

•

The unary operator minus sign (-), indicating that the value
that follows it is negative and should be interpreted in two's
complement form.

respectively. When Q or c is used to represent a register
containing a bias value, it must have a value in the range 0
through 7. When Q or c is used to represent an offset, it may
contain any 16-bit value.

•

The name of one of ODT's registers,
described in Chapters 5 and 6.

•

The current
7.3.2.

location

indicator

used

(.),

the

described

operations
in

Section

In evaluating expressions, ODT proceeds from left to right.
It does
not assign precedence to any operator, or recognize parentheses to
establish precedence.
Therefore, you must be careful to
form
expressions so that they will be interpreted correctly. You can use
the equal sign operator (=), described in Section 7.3.1, to determine
the value of expressions before using them in ODT operations.

2-3

ODT CHARACTERS AND SYMBOLS
Table 2-2 shows how ODT interprets the various forms of address
expressions.
This table assumes a value of 003400 for relocation
register 3 ($R3) and a value of 3 for the constant register ($C).
Table 2-2
Forms of Address Expressions
Address Expression
Input

2.3

ODT Octal
Interpretation

000005

-17

1 77761

3,150

003550

000003

C,10

003410

c,c+c

003406

3,C

003403

Task general
register 3

OPERATOR AND COMMAND SUMMARY

ODT commands are made up of a combination of
letters. Some commands have multiple forms.

symbols

and

uppercase

Table 2-3 summarizes the ODT commands and operators, which are
explained in detail in Chapters 3 through 7. The lowercase letters
used in the command descriptions are expiained in Tabie 2-1.
Table 2-3
ODT Operators and Commands
Format

Meaning

+ or space

Arithmetic operator used in expressions.
Add the preceding argument to the following
argument to form the current argument.
Arithmetic operator used in expressions.
Subtract the following argument from the
preceding argument to form the current
argument. Also used as a unary operator to
indicate a negative value.

, (comma)

Argument separator. Separates the number
of a relocation register from a relative
location to specify a relocatable addresse
(continued on next page)

2-4

ODT CHARACTERS AND SYMBOLS

Table 2-3 (Cont.)
ODT Operators and Commands
Format

Meaning
Radix-50 separator used in constructing
Radix-50 words (see Section 7.3.5).

Current location indicator.
Causes the
address
of the last explicitly opened
location to be used as the current address
for ODT operations.
Argument separator.
Separates
multiple
arguments, allowing an address expression
or ODT register value to be identified.
or

Closes the currently open
location and
is
prompts for the next command. I f ffil
preceded by k, the value k replaces the
contents of the currently open location
before it is closed.

Closes the currently open location, opens
the next sequential location (a word or a
byte, depending on the mode in effect) and
displays its contents. If (ill is preceded
by k, the value k replaces the contents of
the currently open location before it is
closed.

" or k"

Closes the currently open location, opens
the
immediately preceding location and
displays its contents. If " is preceded by
k, the value k replaces the contents of the
currently open location before
it
is
closed.

or k

Interprets the contents of the currently
open location as a PC-relative offset and
calculates the address of the next location
to be opened;
closes the currently open
location, and opens and
displays
the
contents
of
the
new
location
thus
evaluated. If is preceded by k, the value
k
replaces the contents of the currently
open location before it is closed.

@ or k@

Interprets the contents of the currently
open word location as an absolute address,
closes the currently open location, and
opens and displays the contents of the
absolute location thus evaluated. If @ is
preceded by k, the value k replaces the
contents of the currently open location
before it is closed.

ffil
kffil

@
k@

(continued on next page)

2-5

ODT CHARACTERS AND SYMBOLS

Table 2-3 (Cont.)
ODT Operators and Commands
Format

Meaning

> or k>

Interprets the low-order byte
of
the
currently open word location as a relative
branch offset, and calculates the address
of the next location to be opened; closes
the currently open location, and opens and
displays
the contents of the relative
branch location thus evaluated.
If > is
preceded by k, the value k replaces the
contents of the currently open location
before it is closed.

< or k<

Closes the currently open location (opened
by a
, @, or > command), and reopens the
word location most recently opened by a /,
@
, or
If the currently open location
was not opened by a
@, or >, then <
simply
closes and reopens the current
location. If < is preceded by k, the value
k replaces the contents of the currently
open location before it is closed.
A

Represents the aaaress of one of eight
general registers, where n is an octal
digit identifying RO through R7.

$x or $nx

Represents the address of one of ODT's
internal registers, where x is one of the
following alphabetic characters, and n is
one octal digit.
Registers exist within
ODT in the following order:
S

Processor Status register
PS)

(hardware

Directive Status Word
the user's task

Search argument register

Search mask register

Low memory limit register

High memory limit register

Constant register

Quantity register

Format register

Reentry vector register

Breakpoint address registers

for

(continued on next page)

2-6

ODT CHARACTERS AND SYMBOLS

Table 2-3 (Cont.)
ODT Operators and Commands
Format

Meaning
nG

Breakpoint proceed count registers

Breakpoint instruction registers

Relocation registers

SST vector registers

SST (synchronous system trap)
contents registers

stack

Device control LUN
number) registers

unit

(logical

" or a"

Word mode ASCII operator.
Interprets and
displays the contents of the currently open
(or the last previously opened) location as
two ASCII characters, and stores this word
in the quantity register
($Q).
If " is
preceded by a, the value a is taken as the
address of the location to be interpreted
and displayed.

' or a'

Byte mode ASCII operator.
Interprets and
displays the contents of the currently open
(or the last previously opened) location as
one ASCII character, and stores this byte
in the quantity register
($Q).
If '
is
preceded by a, the value a is taken as the
address of the location to be interpreted
and displayed.

% or a%

Word mode Radix-SO operator.
Interprets
and displays the contents of the currently
open (or the last
previously
opened)
location as three Radix-SO characters, and
stores this word in the quantity register
($Q).
If % is preceded by a, the value a
is taken as the address of the location to
be interpreted and displayed.

I or a/

Word mode octal operator.
Displays the
contents of the last word location opened,
and stores this octal word in the quantity
register
($Q). I f I is preceded by a, the
value is taken as the address of a word
location to be opened and displayed.

\ or a\

Byte mode octal operator.
Displays the
contents of the last byte location opened,
and stores this octal byte in the quantity
register
($Q).
I f \ is preceded by a, ODT
takes the value a as the address of a byte
location to be opened and displayed.
(continued on next page)

2-7

ODT CHARACTERS AND SYMBOLS

Table 2-3 (Cont.)
ODT Operators and Commands
Format

Meaning

Interprets and displays expression value k
as six octal digits and stores this word in
the quantity register ($Q).

8 or 9,
RUBOUT,

Cancels the current command and awaits a
new command. The decimal value 8 or 9 is
not a legal character and thus,
when
entered, causes ODT to ignore the current
command. The RUBOUT and
~
functions
are not operational in RSX-llM unless the
terminal
driver
supports
transparent
read/write (a system generation option).

0 r

tTRLIU)

Removes all breakpoints from the user task.

Removes the nth breakpoint
task.

a;nB

Sets breakpoint n in the user task at
address a.
If n is omitted, ODT assumes
the lowest-numbered available sequential

from

the

user

'-----1---!-.L
J..J I. t= Cl I\. }.JV .l. lJ I.. •

Constant regist,er
the
contents of
register).

indicator.
Represents
register $C (constant

'J\6d~~ses d~:t~ ~pace •.·. After· this command>is
:·1·s:~'ueQ , . .· µu·1t . lpterp:re'f;'s' : a:rr refer enc es '.t:o
lo·~~tion~· ias· (:~\fe·t°r:irtfJ: to.. the D-spape of
t:~\:l! . . 1:,ai~l.¢r :(~f)[)(;"l~M~J?~~~> p;l'.lly.~•.•

E or kE
or m;E
or m;kE

Searches memory between the address limits
specified by the low memory limit register
($L) and the high memory limit register
($H).
ODT examines these locations for
references
to
the
effective
address
specified in the search argument register
{$A), as masked by the value specified in
the search mask register {$M). {The mask
should normally be set to 177777 for the E
command.) Such references may be equal to,
PC-relative to, or a branch displacement to
the location specified in $A.
If E is
preceded by k, the value k replaces the
current contents of $A before ODT initiates
the search. If E is preceded by m, the
current contents of $M are replaced with
the value m before ODT initiates
the
search.
(continued on next page)

2-8

ODT CHARACTERS AND SYMBOLS

Table 2-3
(Cont.)
ODT Operators and Commands
Format

Meaning

F or kF

Fills memory locations within the address
limits specified by the low memory limit
register ($L) and the high memory limit
register ($H) with the contents of the
search argument register ($A).
If F is
preceded by k, the value k replaces the
current contents of $A before ODT initiates
the fill operation.

G or aG

Begins task execution, following
these
steps:
sets
BPT
instructions in or
restores BPT instructions to all breakpoint
locations in the task image; restores the
Processor Status Word and user program
registers;
and starts execution at the
address specified by the program counter
(user register $7). If G is preceded by a,
the value a replaces the current contents
of $7 before proceeding as described above.

Using
the
relocation
register
whose
contents are equal to or closest to (but
less than) the address of the currently
open location, ODT computes the physical
distance (in bytes) between the address of
the currently open location and the value
contained in that relocation register. ODT
displays this offset and stores the value
in the quantity register ($Q).

Computes the physical distance (in bytes)
between the address of the currently open
or the last-opened location and the value
contained in relocation register n. ODT
displays this offset and stores the value
in the quantity register ($Q).

a;nK

Computes the physical distance (in bytes)
between address a and the value contained
in relocation register n. ODT displays this
offset and stores the value in the quantity
register ($Q).

L or kL
or a;L
or a;kL

Lists all word or byte locations in the
task between the address limits specified
by the low memory limit register
($L) and
the high memory limit register. If L is
preceded by k, the value k replaces the
current contents of $H before initiating
the list operation. If L is preceded by a,
the value a replaces the current contents
of $L before initiating the list operation.
(continued on next page)
2-9

ODT CHARACTERS AND SYMBOLS
Table 2-3
(Cont.)
ODT Operators and Commands
Format

Meaning

N or kN
or m;N
or m;kN

Searches memory between the address limits
specified by the low memory limit register
($L) and the high memory limit register
($H)
for words with bit patterns that do
not match those of the search argument
specified in the search argument register
($A). Only bit positions set to 1 in the
mask
are
compared.
This
search is
identical in form and function to the word
(W) search described below, except that ODT
performs a test for inequality.

ao or a;kO

Calculates and displays the PC-relative
offset and the 8-bit branch displacement
from the currently open location to address
a;
or
calculates
and
displays the
PC-relative offset and the 8-bit branch
displacement from the specified address a
to the specified address k.

P or kP

Proceeds with user program execution from
the current breakpoint location and stops
when the next breakpoint
location
is
encountered or the end of the program is
reached. If k is specified, ODT proceeds
with program execution from the current
location and stops at the breakpoint only
after encountering it the number of times
specified by integer k.

Quantity register
the
contents of
register).

Sets all relocation registers
to
the
highest address value, 177777(octal), so
that they cannot be used
in
forming
addresses.

Sets relocation register n to the highest
address value, 177777(octal), so that it
cannot be used in forming addresses.

a;nR

Sets relocation register n to address value
a. If n is omitted, ODT assumes relocation
register 0.

S or nS

Executes one instruction and displays the
address of the next instruction to be
executed. If n is specified, ODT executes
n instructions and displays the address of
the next instruction to be executed.

indicator.
Represents
register $Q (quantity

(continued on next page)

2-10

ODT CHARACTERS AND SYMBOLS

Table 2-3
(Cont.)
ODT Operators and Commands
Format

Meaning

Enables ODT's handling of all SST vectors,
and writes the addresses of ODT's trap
entry points into the table used by the
SVDB$ Executive directive.
{See Table 5-2
for a discussion of
the
SST
vector
registers and the $nV/ command.)

W or kW
or m;W
or m;kW

Searches memory between the address limits
specified by the low memory limit register
($L) and the high memory limit register
($H) for words with bit patterns that match
those of the search argument specified in
the search argument register
($A).
ODT
compares each memory word and the search
argument
for
equality under tne mask
specified in the search mask register ($M).
Only bit positions set to 1 are compared.
When a match occurs, ODT displays the
address of the matching location and its
contents.
If W is preceded by k, the value
k replaces the current contents of $A
before initiating the search.
If W is
preceded by m (identified by the semicolon
that follows it), the value m replaces the
current contents of SM before ODT initiates
the search.

Exits from ODT and returns control to the
Executive of the host operating system.

2-11

CHAPTER 3
CONTROLLING PROGRAM EXECUTION

When you run a task image into which ODT has been linked, ODT takes
control before the first instruction of the task is executed.
Information about the task is stored in ODT's internal registers, as
described in Section 5.1.2.
At this point, you can execute your task immediately
commands to affect locations or registers.

3.1

issue

ODT

SETTING AND REMOVING BREAKPOINTS

A common method of using ODT is to set breakpoints at important points
in the task and then to execute the task. When a breakpoint is
reached, execution is suspended.
You can examine locations or
registers to see how your task is executing. You can then change
elements of your task and see how the changes affect execution.

3.1.1

Setting Breakpoints

To set a breakpoint at a location,
command in the following format:

issue

(for

'breakpoint')

a;nB

a
An address expression (in any of the forms described in Section
2.2)
representing the location at which the breakpoint is to be
set.
This location must always be the first word of an
instruction.
n

The number of the breakpoint address register (from 0 to 7) to be
used to store the address of the specified location.
If you omit
n, breakpoint address registers are assigned
sequentially,
beginning with register o.
You can also set a breakpoint by opening a breakpoint address register
as a word location and changing its contents. The address of a
breakpoint address register is its register name, $nB.
Opening and
changing the contents of word locations is described in Chapter 4.
Registers are described in Chapter 5.

3-1

CONTROLLING PROGRAM EXECUTION

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3.1.2

Removing Breakpoints

You can clear breakpoint address registers
(and
thus
remove
breakpoints) using the nB command, where n represents the number of
the register. If you omit n, all breakpoint address registers are
cleared. You can also clear a breakpoint and reset it by specifying a
new address expression for a breakpoint address register, using the
a;nB command.
The following example shows how
reset:

breakpoints

are

set,

cleared,

and

_B
_1020;B
_2030;B
_3040;B
_4050;B
_2032;1B
_38

At this point, breakpoint address register O is set to location 1020,
breakpoint address register 1 is set to 2032, and breakpoint address
register 2 is set to 3040.

Breakpoint address register 3 is clear.

Note that ODT generates a carriage return, a line
prompt immediately when you type the letter B.

feed,

and

new

You can also clear a breakpoint register by opening it as a word
location whose address is $nB and changing its contents, as described
in Chapter 4.

3.2

BEGINNING PROGRAM EXECUTION

To begin execution of your task, type the G (for 'go') command.
command has the following effects:

This

•

The task's starting address is returned to the program counter
from the ODT general register in which it was stored.

•

The task's stack and other general registers are restored.

•

The contents of each location at which a breakpoint was set
are swapped with the contents of the corresponding breakpoint
instruction register.
(These registers, described in Section
5.2, are initialized by ODT to BPT instructions.)

•

Execution of the task begins.
3-2

CONTROLLING PROGRAM EXECUTION
Execution continues until it reaches one of the following:
•

A breakpoint

•

An error of type BE, EM, FP, IO, or TR (described in

Appendix

•

The end of the program

Once the program is executing, Y()~ cCip~ot ;=;t:()P ~~ ~}{c=ept >bX ~b?FtiI1~
~.h~ ......... pr?9.r~~ .~P8 ~e,;=;t:}~r~ip~>·~·~ ~ . . ·. ··(~~}{J~l.~~F-~·~µs.•:~Jil~: •. '4~·9··E;1Y§·~e~~. ·•*~P:+~g~.

When the task reaches a breakpoint, ODT executes the BPT instruction
that was swapped into the breakpoint location. This instruction has
the following effects:
•

Task execution is suspended.

•

The contents of the user task general registers are stored
ODT internal registers.

•

The original contents are restored to all breakpoint locations
from the breakpoint instruction registers where they have been
stored.

•

ODT issues a message indicating that a breakpoint has been
reached.
This message has the format nB:a, where n is the
breakpoint address register number and a is the location of
the breakpoint that was stored in that register.

•

ODT issues its prompt.

While task execution is suspended, you may issue any ODT command.

3.3

CONTINUING PROGRAM EXECUTION

You can continue program execution using either the P (for "proceed")
command, the G command, or the aG command. Execution continues until
a breakpoint, the end of the program, or an error of the types
specified above is reached.
Use the P command to continue execution after a breakpoint. When you
type P, the contents of the user general registers are restored, the
BPT instructions are swapped into all breakpoint locations, and task
execution resumes at the instruction following the last logical
instruction executed. If execution stopped because of a breakpoint,
it will resume at the breakpoint location. If execution stopped
because of an error, it will resume at the location following the
error location, not at the error location itself.
You can resume execution using the G command; however, because the G
command does not transparently restore the breakpoint instruction, you
should not use it to resume execution after a breakpoint.
To resume execution at a specific location, use the aG command.
The
argument a is an address expression representing the task location.
The address specified must correspond to a word location boundary,
that is, an even location. Registers are affected as described in
Section 3.2, and execution begins at the specified location.

3-3

CONTROLLING PROGRAM EXECUTION
Note that you can use only G or aG to begin execution of a task.
If
you type P when no G command has been executed, ODT responds with a
question mark and a new prompt.

3.4

USING THE BREAKPOINT PROCEED COUNT

If you set a breakpoint inside an execution loop, you may want to
suspend execution only when the loop has been executed a certain
number of times. You can specify how many times a loop should be
executed by including a breakpoint proceed count with the P command,
in the form kP.
The loop is executed k-1 times;
execution is
suspended when the breakpoint is reached for the kth time.
The kP command is associated only with the breakpoint that has most
recently occurred.
The count k is stored as an octal value in a
breakpoint proceed count register ($nG), where n is a
number
corresponding to the number of the appropriate breakpoint address
register.
You can examine the breakpoint proceed count registers, or set them
directly, at any time following the procedures for examining and
setting word locations described in Chapter 4.
These registers are
all initialized by ODT with the value 1. If you change the value of a
register, the new breakpoint proceed count will be used when the
breakpoint is next encountered as a result of the P command.

3.5

STEPPING THROUGH THE PROGRAM

Another method of executing a task in stages is to use the s (for
"step") command.
With this command, you can execute user task
instructions one at a time or several at a time.
The command has the format nS, where n is the number of instructions
that ODT should execute before suspending execution. The default
value of n is 1.
When n instructions have been executed, ODT susoends task execution
and prints a message of the form 8B:a, where a is the location of the
next instruction to be executed.
(The format of a is relative by
default, as explained in Chapter 4.) ODT then prompts for another
command.
The S command is implemented through the T-bit in the Processor Status
Word (described in Appendix B). The T-bit is set when you issue the
command; when the nth instruction is executed, control is returned to
the user.
The following example shows ODT's response to
commands described in this chapter:
1,1052;8
-1, 2052; lB
-G
OB:l,001052
p

TB:l,002052

SB:l,002056

SB:l,002062

3-4

the

program

execution

CHAPTER 4
DISPLAYING AND ALTERING THE CONTENTS OF LOCATIONS

During an ODT session, you can
alter
the
contents -- either
instructions or data -- of locations in your task. To alter the
contents of a location, you must first "open" the location.
You open a location by displaying its contents, using any of the
commands
described in Sections 4.3 through 4.9.
The contents
displayed are automatically placed into the quantity ($Q) register.
ODT displays a location by showing the address followed by a mode
operator
(either word mode or byte mode, depending on the size of the
location opened) and the contents of the location.
The format in
which the location is displayed is controlled by the contents of the
format register ($F), as described in Table 5-1.
By default, ODT
displays addresses in relative form whenever it has the information
necessary to construct such an address:
the number of the relocation
register containing the bias value closest to (but less than) the
address, and the relative location of the address from that value.
When this information is not available, ODT prints the address in
absolute form.
(Relative and absolute forms are described in Section
2.2.1.)
ODT does not generate a carriage return or line feed after displaying
the contents of a location. Until the location is closed, the cursor
remains on the same line, wrapping around as necessary.

4.1

ALTERING THE CONTENTS OF A LOCATION

You alter the contents of a location by typing the new contents
immediately after the displayed contents. The new contents can be an
absolute octal value (of up to six digits) or an expression equivalent
to a 6-digit octal value, as described in Section 2.2.2.
If you enter an octal value, you may omit leading zeros.
In the following examples, the value 1234 is substituted for the value
123450 in the location represented by the address expression 2,0. The
value 177426 (the two's complement result of the expression 16-370)
replaces the value 000000 in the location represented by the address
expression 4,10.
_2,0/123456 1234
_4,10/000000 16-370

4-1

DISPLAYING AND ALTERING THE CONTENTS OF LOCATIONS
After you have altered the contents of a location, you can verify the
new contents by displaying them in a variety of modes, using the
commands described in Section 4.10. These commands do not close the
location.
You can also verify the contents by closing the location
and then reopening it, so that the new contents are displayed.
Before you can alter the contents of a new location,
the currently open location.

4.2

you

must

CLOSING A LOCATION

To close a location without automatically opening another location,
enter the
@@command. This command has no effect on ODT when no
location is open.
The
@TI)
command generates a carriage return and a
then prompts for another command, as follows:

line

feed.

ODT

1,200/450123 @TI)
To close a location and automatically open another location, you can
use any of the following commands, described in Sections 4.4 through
4.9:

4.3

OPENING WORD AND BYTE LOCATIONS

ODT interprets the slash character (/) as a word mode octal operator
and the backslash character (\) as a byte mode octal operator. Using
these operators in ODT commands is the most direct way to open word
and byte locations.
These commands are described in the following
sections.
You can also open word and byte locations and display their contents
in ASCII, or open and display words in Radix-50.
Using these modes is
described in Section 4.10.

4.3.1

The a/ and a\ Commands

To open a word location beginning at an address, type an address
expression corresponding to that address,
followed by a slash, in
response to the ODT prompt. The address must be even numbered.
ODT
opens the word location beginning at the specified address and
displays the contents of that location as a 6-digit octal number.
To open a byte location, type an address expression corresponding to
an odd- or even-numbered address, followed by a backslash. ODT opens
the byte location beginning at the specified address and displays the
contents of that location as a 3-digit octal number.
The following examples show the effects of the a/ and a\ commands:
1000/012675 (BTIJ
1001\025 IBITl

4-2

DISPLAYING AND ALTERING THE CONTENTS OF LOCATIONS
4.3.2

The I and \ Commands

You can use the word mode and byte mode octal operators without
address arguments to reopen the location last opened.
The I command
opens the word location last opened and displays the word at that
locationo
The \ command opens the byte last opened and displays the
contents of that byte.
(If the last location opened was a word,
the
byte opened and displayed is the low-ordered byte of that word.)
When no location is open, you can also use the
command to
last-opened location, as described in Section 4.5.
A

4.3.3

open

the

mode

and

Moving Between Word and Byte Modes

The word mode and byte mode octal operators establish
byte mode, respectively.

word

Once you have opened a location using the word mode octal operator
(/), all locations subsequently opened will be octal words until the
mode is changed.
Once you have opened a byte location using the byte
mode octal operator
(\), all locations subsequently opened will be
octal bytes until the mode is changed.
You can change from word to byte mode by opening a location with the
a\ command or by specifying an odd-numbered address as the value a in
the a/ command. Subsequent locations will be displayed as bytes until
a word location is explicitly opened using an even-numbered address as
the value a in the a/ command (or the a" or a% commands, described
in
Section 4.10).
The following example shows a change from word mode to byte mode and
back again using an odd-numbered address in the a/ command.
{The
@
command, which opens the next sequential location in whatever mode is
currently in use, is described in Section 4.4.)
1001/123 321 ffi)
-; 321 @
001002 \021

001003 \010

001004 \201 ffi)
_1006/102054
If a word location is open, you can examine its low-order byte by
typing the byte mode octal operator
(\)
immediately after the
displayed contents of the location.
The location is not closed and
you do not leave word mode.
The following example shows this use of
the byte mode octal operator:
lOOn/102054 \054

1010/012345
You can also examine words or bytes of an open location
Radix-50 modes, as described in Section 4.10.

4-3

ASCII

DISPLAYING AND ALTERING THE CONTENTS OF LOCATIONS
4.4

OPENING THE NEXT SEQUENTIAL LOCATION

To open and examine successive locations, use the
@
command.
The
@
command closes the currently open location and opens the next
sequential location.
If the currently open location is a word,
the
next sequential location will be opened as a word.
If the currently
open location is a byte, the next sequential location will be opened
as a byte.
If you specify a value before entering the
@
command, that value
replaces the contents of the open location, as described in Section
4.1.

4.5

OPENING THE PRECEDING LOCATION

To back up in your task and open the location preceding the location
that is currently open, use the
command. This command closes the
currently open location.
If the currently opened location is a word
location, the command opens the word location immediately preceding
it.
If the currently open location is a byte, the
command opens the
preceding byte.
A

If no location is currently open, the
command opens and displays the
contents of the last-opened location, a word or a byte, depending on
the mode currently in effect.
A

If you specify a value before entering the
command, that value
replaces the contents of the open location, as described in Section
4.1.
The following example shows the use of the
@
and
commands.
Location 232, relative to the bias contained in relocation register O,
is opened as a word and its contents are altered. In response to the
@
and
commands, ODT proceeds to the next word location and then
backs up to 232 to display the new contents.
A

0,232/005036 005046 @
0,000234 /012746
0,000232 /005046

4.6

OPENING ABSOLUTE LOCATIONS

To proceed from an open location to the location whose address is
contained in that location, use the @ command. This command closes
the currently open location and uses the contents of that location as
the absolute address of the next location to be opened. You can
specify new contents for the original location by entering a value
before the @ command, as described in Section 4.1.
You can only use the @ command if the currently
word.

open

location

Opening an absolute location does not necessarily mean that the
location is displayed as an absolute address.
As shown in the
following example, where relocation register 2 is set to contain the
bias value 370 (as described in Section 5.2.1), ODT still by default
displays the location as a relative address.

370;2R
-2,noo/012345 12746@
2,012356 /027117
4-4

DISPLAYING AND ALTERING THE CONTENTS OF LOCATIONS
Location 12356 relative to bias value
absolute address specified, 12746.

4.7

370

equivalent

the

OPENING PC-RELATIVE LOCATIONS

To open a location relative to the program counter, use the
command.
This command adds the contents of the currently open locaton to the
value of the program counter, which is the address of the currently
opened location plus 2. ODT closes the currently open location and
opens the location whose address is the result of its calculation. If
you enter a value before the
command, this value replaces the
contents of the open location and is used in the calculation.
You can only use the
word.

command if the currently

open

location

If the currently open location contains an odd number (or if it
contains an even number but is already a byte location), so that the
calculated address does not fall on a word boundary, the
command
opens a byte at the location calculated.
The following examples show how the

command is used:

1000/000040
001042 /052407
0,232/012345
0,012601 /041
0,232/012345 123456
0,123712 /020301

4.8

OPENING RELATIVE BRANCH OFFSET LOCATIONS

Use the > command to open a location at a branch offset relative
the currently open location. The offset is calculated as follows:

The low-ordered byte of the contents of the currently open
location is interpreted as a signed value. A negative value
results in a negative branch offset.

This value is multiplied by 2.

The resulting offset is added to the PC value, which
address of the currently open location plus 2.

the

The > command closes the currently open location and opens the
location whose address is the value calculated. Its effects are shown
in the following examples:
1,66/005046>
I,000204 /000601
1032/000407 301>
000636 /000010

If you specify a value before entering the > command, the low-order
byte of that word is used in the offset calculation. The value
replaces the contents of the open location, as described in Section
4 .1.

4-5

DISPLAYING AND ALTERING THE CONTENTS OF LOCATIONS
4.9

RETURNING FROM A CALCULATED LOCATION

If you have used any of the three address calculation commands
described in the last three sections (@,
, or >) and wish to return
to the location from which you began to calculate addresses, use the <
command.
This command closes the currently open location and reopens
the word most recently opened by a / ,
@ , or
command.
A

The following example shows the use of the

< command:

1036/021346
To34/10102s 101036_
102074 /OOOOUU @
000000 /000000 >
000002 /000102 <
001034 /101036
A

If the currently open location was not opened by a @,
, or > command,
the < command simply closes and reopens the current location.

USING DIFFERENT OUTPUT MODES

4.10

The examples in the previous sections have shown ODT output in word
mode octal and byte mode octal. However, you can also use ODT to
display the contents of locations in word or byte mode ASCII and word
mode Radix-50.
These modes follow the same rules as word mode
octal:

octal

and

byte

mode

•

You can use the @ command to open succeeding locations in
the same mode in which the currently open location was opened.

•

You can enter any mode operator to display the contents of the
currently open location in another mode without changing the
mode in effect or closing the location.

The interaction of mode operators was shown in Section 4~3.3, where a
location opened in word mode octal was examined in byte mode. The
@
command that followed opened the next sequential location in word
mode octal.

4.10.1

ASCII Mode

ODT interprets the double-quote character (") as a word mode ASCII
operator and the apostrophe (') as a byte mode ASCII operator. You
open a location in word mode ASCII with the a" command and in byte
mode ASCII with the a' command.
If you open a location in any mode and then type a word mode ASCII
operator, the contents of the open location will be displayed as two
ASCII characters but the location will not be closed.
If you open a location in any mode and then type a byte mode ASCII
operator, the contents of the low-order byte of the open location will
be displayed as one ASCII character. The location will not be closed.

4-6

DISPLAYING AND ALTERING THE CONTENTS OF LOCATIONS
The following examples show these uses of the ASCII operators:
_0,440"AB
_2,lOO'H
Q' 232/034567

I W

"W9 lbEJ

0,000234/000123 filITJ

•s

If you enter the word mode ASCII operator to examine the contents of a
location
and the location is aligned on a byte boundary (an
odd-numbered address), ODT will not return an ASCII character.
Instead,
it will display the contents of the location in the mode
currently in effect, as follows:
0,000235\025 "025

4.10.2

Radix-SO Mode

ODT interprets the percent sign (%) as a word mode Radix-SO operator.
(There is no byte mode Radix-SO operator, since Radix-SO is a method
of fitting three characters into a word and cannot be used in smaller
units.)
You can use the Radix-50 operator to open locations. The a% command
opens the location specified in the address expression a and displays
its contents as three Radix-50 characters= The % command reopens the
last-opened
word
and displays its contents as three Radix-SO
characters.
If a word location is open, you can enter the % operator to examine
the Radix-SQ contents of that location without closing the location.
The following examples show these
operator:

uses

the

word

mode

Radix-50

_4, 232%IG1
4, 232/034567 filITJ
=%IG1
_4,000232/034S67 %IG1
Like the word mode ASCII operator, the Radix-SO operator cannot be
used to interpret values beginning on byte boundaries. If you enter
the Radix-SO operator when the currently open location has an odd
address, ODT simply displays the byte value in the current mode.
Remember that you must enter new contents for a location as an octal
value or an expression. not as Radix-50 characters. To determine the
octal equivalent of Radix-SO characters, use the Radix-50 evaluator
(*), as described in Section 7.3.5.

4-7

CHAPTER 5
USING REGISTERS

ODT has a number of 16-bit registers. Some of these registers are
used for temporary storage of values;
some contain values used
repeatedly throughout the execution of your task under ODT.
All of
the registers are word locations that you can examine and alter.
Each ODT register has a unique name beginning with a dollar sign
($).
The $ and the character or characters that follow it make up an
address expression that identifies the register.
This chapter explains how ODT uses its registers. Tables 5-1 and
summarize the registers and are useful for quick reference.

5.1

5-2

GENERAL REGISTERS

ODT has eight general registers, numbered $0 though $7, which store
the contents of the user program's general registers when ODT has
control. These registers are automatically set when ODT first is
invoked and when a breakpoint occurs. They can also be set by the
user ..

5.1.1

Examining and Setting General Registers

To examine a general register, enter the register name as the address
expression in the a/, a", or a% command.
For example, you can enter
any of the following:
$7/
$3%
$1"

ODT opens a register like any other word location. You can then alter
the contents of the register or use any of the following commands, as
described in Chapter 4:
~
=-'

@ II %

ODT treats the general registers as sequential word locations.

5-1

USING REGISTERS
5.1.2

Contents of General Registers

When you issue the RUN command and ODT initially gains control,
information about the user task is stored in the general registers as
follows:
Register

Contents

Task's entry-point address

First three characters of task's
(Radix-50)

run-time

name

Last three characters of
(Radix-50)

run-time

name

$3-$4

Version number of user task if the program
included the
.IDENT directive; otherwise, the
version number of ODT

task's

When a breakpoint occurs, ODT's general registers store
of the task's general registers.

5.2

the

contents

ODT INTERNAL REGISTERS

The ODT internal registers store values for use during a debugging
session.
For example, they store the locations of breakpoints and the
memory limits to be used in search operations.
Each register is a
16-bit location that you can open by specifying the register name as
the address expression with any ODT command that opens a word
location. You can enter any of the following:
$3R/
$A"
$C%
It is rarely useful to
Radix-SO mode.

examine

internal

ASCII

You can alter the contents of these registers as you would the
contents of any word; however, this is not recommended in some cases,
as described in Tables 5-1 and 5-2.
Ten of the ODT internal registers are single registers;
that is,
there is only one register for each function. You refer to one of
these registers as $x, where x is an alphabetic character. Table 5-1
lists these registers in alphabetical order.
In the task, they appear
in the order listed in Table 2-3, that is:
$5 $W $A $M $L $H $C $Q $F $X
You can access these registers as sequential word
order, as in the following example:

$s/oooooo till
$W /000001 QJl
$A /000000 @
$M /177777

5-2

locations

this

USING REGISTERS
Table 5-1
ODT Single Registers
Register

Function

Search argument register.
You set this
a word search argument by opening
operator, or to a byte search argument
with the \ operator.
Can also be set
memory commands described in Chapter 6.

Constant register.
The 16-bit value in
this
register can be used as an address expression or a
value through the constant register indicator C,
described in Sections 2.2.2 and 5.3.1.

Format register. When set to zero, all user task
addresses are displayed by ODT in relative form, if
an appropriate bias value is available in one of
the relocation registers.
When set to any other
value,
user task addresses are
displayed
in
absolute form.
See Section 2.2.1 for a description
of absolute and relative forms of addresses.

High memory limit register.
The location contained
in this register
is the upper location limit for
ODT search, list,
and
fill memory operations.
Initialized to O.

Low memory limit reqister.
The location contained
in this -register -is the lower location limit for
ODT search, list,
and
fill memory operations.
Initialized to O.

Search mask register.
You set this register to a
word search mask by opening with the I operator, or
to a byte search mask by opening with the \
operator.
Can also be set by arguments specified
with the memory commands described
in Chapter 6.
Initialized to minus one, 177777(octal).

Quantity register.
ODT sets this register to the
last value displayed,
as described
in Section
5.3.2.
$Q is also used for
the results
of
expression calculations using the = operator.

Processor status register.
Stores the Processor
Status Word
(see Appendix B) resulting from the
last instruction executed prior to a breakpoint.
Users do not normally change the contents of this
register directly.

Directive Status Word
register.
Contains
the
Directive Status Word (DSW) of the task, indicating
the success or specific cause of rejection of the
most recently executed directive.
The contents of
this register are maintained across breakpoints.
See the Executive Reference Manual of the host
system for details on the DSW.

Reentry vector register.
A positive value causes
ODT
to retain register values for successive
entries of ODT, as described in Section 5.2.2.

5-3

USING REGISTERS
The other ODT internal registers are grouped into sets of eight or
three sequential word locations.
The
integer n
is part of the
register name, in the form $nx;
you must always include n,
even if
its value is O.
Table 5-2 lists the register sets alphabetically.
In the task,
they
appear as sequential word locations in the order listed in Table 2-3,
that is:
$nB $nG $nI $nR $nV $nE $nD
Table 5-2
ODT Register Sets
Register

Range of
n

$nB

0 -

,... -- ._

-? 11LJ

$nE

- 2

Function

Breakpoint address register
n.
Contains
user-specified
address
of
location
(breakpoint) in the user task whose contents
are to be swapped with the contents of $nI
when a G or P command is executed.
A ninth
register,
$8B, is used by ODT for single-step
execution.
.._
- - -- ·- -- - ,
-·--'---'
UUllllJt::
L )
(logical
U11.L l..
LUN
Dt:vict: l.:Ulll..1.U..l
register n.
As described in Section 6.1.4,
register $OD contains the LUN of the user
terminal and register $1D contains the LUN of
Register $2D contains the
the console device.
normally a default
QIO
event flag number,
value of 000034 (octal).
-~- ~

The top three
SST stack contents register n.
items on the user program stack are placed
into these registers when a synchronous system
,....,....,...,..,...c:"'
,...
... the
... ,:i
Stack ,.."""'f-o1""'111f-t:.':'I ,:i,,..,.._,,.
v ..
t"
u '-1:"'-'J.'\.A
as explained in the
type of trap taken,
reference
manual
Executive
of the host
operating system.
.f-V"'~Y"'\

..... 0.

V'-'-'UJ..t.:Je

'-'V.1.J.\-~.1.&\....;1

$nG

0 -

Breakpoint proceed count register n, where n
corresponds to breakpoint address register n.
Contains number of times
the
breakpoint
location should be encountered before the
breakpoint is recognized.
Each register
is
initially set to 1 and can be set through the
kP command (see Section 3.4), or by opening
$nG
and altering
its contents.
A ninth
register, $8G, is used by ODT for
single-step
execution.

$nI

register
instruction
n.
Breakpoint
Initialized to contain a BPT instruction, op
with
the
which is swapped
code 000003,
contents of register $nB when the G or p
The functions of the BPT
command is executed.
I instruction are described in Section 3.2. A
is used by ODT for
$8I,
ninth register,
single-step execution.
(continued on next page)

5-4

USING REGISTERS
Table 5-2 (Cont.)
ODT Register Sets
Register

Range of

Function

$nR

0 - 7

Relocation
register
n.
Contains
the
relocation
bias
of a relocatable object
module, enabling ODT to display user task
addresses in relative form, if $F is set to 0
I (see Table 5-1).
ODT
initializes
each
register to 177777(octal).

I
$nV

0 - 7

SST vector register n.
Contains entry-point
address
of
ODT
routine for handling a
I. synchronous system trap. If both ODT and the
user program have SST vectors enabled for the
trap, ODT automatically receives the trap,
except for vector 6 ($6V) , which must be
I1 explicitly enabled through the V command (see
Table 2-3).
ODT handling of a trap can be
disabled
by
clearing
the register;
the user
I
I program vector then receives the trap.
Registers correspond to traps as tollows:

I
I

Reg$is vter

I•

Odd address reference in word
instruction
(also,
on
some
processors, illegal instruction
executed)

$1V

Memory protection violation

$2V

T-bit trap
executed

$3V

IOT instruction executed

$4V

Reserved or
executed

$5V

Non-IAS/RSX-11
executed

$6V

TRAP instruction executed

$7V

PDP-11/40
exception error

SST Vector

BPT

illegal
EMT

instruction

instruction
instruction

floating-point

The following sections describe the functions of ODT
internal
registers $nR, $X, $C, and $Q in greater detail. Registers used in
memory operations ($L, $H, $M, $A, and $nd) are described in Chapter
6.

5-5

USING REGISTERS
5.2.1

Relocation Registers

ODT's eight relocation registers allow you to refer to locations by
relative addresses instead of absolute addresses. Since relative
addresses are easy to determine from source file listings, using them
makes debugging faster and simpler.
When ODT is initialized, each relocation register is
set
to
177777(octal).
This is the highest possible memory address and
the~efore cannot be used in constructing address expressions.
To make
a relocation register useful, you place in it the base address of a
relocatable module or another convenient point, as explained in
Section 2.2.1.
This address functions as a relocation bias that is
added to the relative address in an address expression to form the
absolute address of a location.
You obtain the base (starting) address of a module by consulting the
memory allocation synopsis in your task map. This part of the map
gives the octal starting address of each program section and each
module that makes up a program section. It also shows the extent of
the module, in octal and decimal.
The following figure shows a memory allocation synopsis - for
task:
SECTION

TITLE

ID ENT

brief

FILE

. BLK.:(RW,I,LCL,REL,CON) 001264
001012 00522 •
001264 000574 00380.

HIYA

HIYA. OB.1: l

$$RESL: (RO,I,LCL,REL,CON) 010152 000112 00074.
$$$0DT:(RW,I,GBL,REL,OVR) 002276 005654 02988.
002276 005654 02988. ODTRSX M06

ODT.OBJ;l

5.2.1.l Setting Relocation Registers - You
can
set
relocation
registers either by opening them as word locations and altering them,
or by using special ODT commands that affect relocation registers.
To open a relocation register ~~ an octal word; use the register name
$nR as the address expression a in the a/ command (or any of the other
commands described in Chapter 4 that open words). You can enter a new
value for the register after examining the existing contents.
The ODT command a;nR sets register $nR to the location specified
address expression a. If you omit n, register $OR is assumed.

5.2.1.2 Clearing Relocation Registers - To
remove
a
relocation
register from consideration in calculating addresses, enter the nR
command, where n is the number of the relocation register.
This
command sets the register to 177777 (octal), so that it is no longer
useful in constructing address expressions.
If you omit n, all
relocation registers are set to 177777(octal).

5-6

USING REGISTERS
5.2.2

The Reentry Vector Register

If you have fixed a task in memory (using the FIX command, described
in the RSX-llM/M-PLUS MCR Operations Manual, the IAS MCR Users Guide,
and the IAS PDS User'S--Guide), you can use the --reentry vector
register,
$X,
to maintain register values set during your debugging
session and to keep track of your access to the task.
The reentry vector register contains the value -1 when your task is
built.
When you execute the task for the first time, the register
value is incremented to O.
The O value causes CDT to omit the task
name from the invocation message line (described in Section 1.3) the
next time you enter the task.
This omission indicates that the task
is fixed in memory.
If you intend to reenter the task for further debugging, you should
set $X to 1 or another positive nonzero value. As long as the value
of $X is positive and nonzero, the fixed task is reentered at the
value stored in $7
(the program counter), and the values stored in
ODT's registers are maintained.
You can continue to debug the task
using the breakpoints, constants, and other values established in an
earlier debugging session.
If $X is not positive, all registers are
initialized when you reenter the task.
You can use the reentry vector register as a counter to record how
many times you have entered a
fixed task.
To do this, set the
register to 1 the first time you enter your task and increment it each
time you access the task again.

5-7

CHAPTER 6
MEMORY OPERATIONS

ODT allows you to perform three
memory in your task:

kinds

operations

blocks

•

Search memory for bit patterns or references to locations

•

Fill memory with a value

•

List blocks of memory on an output device

Section 6.1 describes how you establish the registers used in memory
operations.
The subsequent sections of this chapter describe how you
use ODT commands to perform these operations.

6.1

REGISTERS USED IN MEMORY OPERATIONS

ODT memory operation commands function between limits in memory that
you must specify. Search and fill commands require an argument to be
searched for or deposited. Search operations also require a search
mask.
ODT maintains registers to contain all of these values. You can set
these registers as word or byte locations (as described in Chapters 4
and 5) before issuing memory operation commands. You can also specify
a search argument and a search mask as the k and m arguments in the
commands themselves.
If you do not specify an argument in one of
these commands, ODT uses the current contents of the appropriate
register;
if you specify an argument, that argument replaces the
contents of the register.

6.1.1

Search Limit Registers

There are two search limit registers: $H, containing the high memory
limit for a search, fill, or list operation; and $L, containing the
low memory limit. You deposit a memory location in one of these
registers by opening it as a word location and changing its value to
the address of the location. You can specify the location in either
absolute or relative form, as follows:
$L/OOOOOO 1000 (BIT)

=.; 001000 2,4060 @
_$H/OOOOOO 3,100

6-1

MEMORY OPERATIONS
If the value in $L is greater than the value in $H, ODT will not
perform
the
memory operation requested using these registers.
Instead, ODT displays its prompt.

6.1.2

Search Mask Register

ODT initializes the search mask register $M to 177777(octal), so that
all bits are set to 1. You set the value of the register by opening
it as a word location and changing its value. Only bit positions set
to 1 in the search mask are compared in the search operation. The
value compared is that set for the corresponding bit position in the
search argument register $A.
You can also set register $M by specifying a value m,
followed by
semicolon, in any of the search commands described in Section 6.2.

6.1.3

Search Argument Register

The search argument register $A contains the value searched for
in a
memory search operation or filled with in a memory fill operation.
You can set this value by opening register $A as a word or byte
location and changing its contents, or by specifying the argument k in
one of the search commands described in Sections 6.2 and 6.3 •
As noted in Section 6.1.2, only bit positions Set
mask are compared in any memory search operation.

6.1.4

.._

_ , :-

L.V

..I.

.LU

---~--,_

:::it:::a.L 1.,;u

Device Control LUN Registers

The device control LUN registers $OD and $1D contain the logical unit
numbers of
(respectively)
the user terminal (TI:) and the console
device (CL:). You specify one of these registers as the value n in
the n:a;kL command
(described in Section 6.4.1) to indicate what
device should be used for a listing.
The Task Builder assigns default values for these registers:
000007
(octal) for $OD and 000010 (octal) for $1D. To reset these registers,
you can link your task using the TKB option UNITS=keyword as described
in the RSX-llM/M~PLUS Task Builder Manual or the IAS Task Builder
Reference Manual.
You may find it more convenient simply to assign a new value for CL:
before beginning your debugging session.
Use the MCR command ASN or
the DCL command ASSIGN, in one of the following formats:
ASN devicename=CL:

(MCR command)

and
ASSIGN CL:

devicename

(DCL command)

For more information on these commands,
interpreter manual for your system.

6-2

see

the

command

line

MEMORY OPERATIONS
6.2

SEARCHING MEMORY

There are three memory search commands: W, N, and E. Each of these
commands has several forms, depending on the number of registers that
already contain values that you want to use in the search operation.
The following sections describe these command forms.

6.2.1

Searching for a Word or Byte

The W command searches for occurrences of the search argument
(comparing bit positions specified in the search mask) within the
range set by the contents of the search limit registerse
The full form of the command is m;kW, where m specifies the search
mask and k specifies the search argument. However, you can omit
either or both of these arguments if the corresponding registers
contain the values that you want to use. If you omit m, you should
also omit the semicolon argument separator.
ODT performs an exclusive OR (XOR) operation on the contents of each
location and the search argument; it then ANDs the result of this
comparison with the search mask. A result of zero indicates a match.
When a match occurs, ODT prints the address and contents of the
location and repeats the search operation until the high memory limit
is reached.

6.2.2

Searching for Inequality of a Word or Byte

The N command is the opposite of the W command:
It examines the
search range for words or bytes that do not exactly match the search
argument in the positions determined by the search mask.
The full form of the command is m;kN, where m specifies a search mask
and k specifies a search argument. As with the W command, you can
omit either argument or both.
The search algorithm proceeds like that for the W command, except that
a location's address and contents are only displayed by ODT when the
AND operation has resulted in a nonzero value.

6.2.3

Searching for a Reference

The E command searches for memory locations containing instructions
whose execution results in a reference to the task address specified
as the search argument. Because the search argument represents an
address, it can only be a word, not a bytee
The full form of the command is m;kE, where m represents the search
mask and k the search argument. You can om1~ either or both of these
arguments if you want to use the values already contained in registers
$M and $A. For effective use of the E command, the search mask should
be set to 177777(octal), so that all bit positions are compared.

6-3

MEMORY OPERATIONS
ODT compares each location within the search limits and displays the
address and contents of locations that contain any of the following:

6.3

•

The search argument as an absolute address

•

A relative address offset reference to
specified as the search argument

the

absolute

address

•

A relative address branch reference to
specified as the search argument

the

absolute

address

FILLING MEMORY

The F command fills the block of memory defined by the high and low
memory limit registers with the value in the search argument register.
You can set this register using the command $A/ (as described in
Section 6.1.3), or specify the argument k with the F command, in the
form kF.
If the last location opened was a word, the memory range is filled
with words;
if the last location was a byte, the memory range is
filled with bytes. The low-order byte in register $A is used.
In the following example, word locations 1000 through 1776 are set to
zero and byte locations 2000 through 2777 are filled with ASCII spaces
(40 octal):
_lOOO;lR
_2000;2R
3000;3R
=$L/000000 1,0 IBfll
_$H/000000 2,-2 IBfll
OF
=$L/001000

I'\

L.1V

_$H/001776 3,-1
_$A\000 40 ~
_F

6.4

IBfll

LISTING MEMORY

The L command lists on an output device the block of memory defined by
the high and low memory limit registers. The following sections
describe how you request a listing and what the listing looks like.

6.4.1

Command Format

The L command has the following format:
n;a;kL
n

The device control LUN register number for the listing operation.
A value of 0 indicates the user terminal (TI:); any other value
is interpreted as 1 and indicates the console listing device
(CL:). The default is 1.

6-4

MEMORY OPERATIONS

a
The low memory limit for the listing operation.
If you omit a,
the value of register $L is used.
If you specify a, that value
is placed in SL.
k

The high memory limit for the listing operation.
If you omit k,
the value of register $H is used.
If you specify k, that value
is placed in $H.
You must include the semicolon argument separator (;) between a and k
if you specify the argument a.
You must include two semicolons if you
specify the argument n.

6.4.2

Listing Format

A memory listing is formatted in groups of eight units.
Each line
begins with a
location,
in relative form if possible (see Section
2.2.l), followed by eight words or eight bytes in the current output
mode.
A memory listing is displayed in whatever mode was used to open
the last opened location.
Thus you can list blocks of memory in word
mode octal, byte mode octal, word mode ASCII, byte mode ASCII, or word
mode Radix-50, as described in Section 4.10.
The following example shows the output displayed on the output device
in response to various listing commands.
Note that the question mark
displayed in response to the ' command is not in this case ODT's error
indicator;
it is merely the ASCII character stored in the next byte.
Example 6-1

ODT Listing Format

1344; 1400L
001344 /047503 046125 020104 020111 040510 042526 054440 052517
001364 /020122 040516 042515 050040 042514 051501 037505
1344" CO L
001344 "CO UL D I
HA VE y OU
001364 "R NA ME p LE AS E?
1344\ 103 L
l344 \103 117 125 114 104 040 111 040
1354 \110 101 126 105 040 131 117 125
1364 \122 040 116 101 115 105 040 120
1374 \114 105 101 123 105
1344' C L
001344 'C 0 u L D I
001354 'H A V E y 0 u
p
001364 'R N A M E
001374 'L E A S E
I ?
1300;R
SH/001400 0.101
1344' C L
0,000044 'C 0 U L D I
0,000054 'H A V E y 0 u
0,000064 'R N A M E p
0,000074 IL E A S E ?

6-5

CHAPTER 7
PERFORMING CALCULATIONS

ODT performs a variety of arithmetic
calculations
useful
in
determining offsets, Radix-50 equivalents, and other values. The
following sections describe commands that perform
calculations.
Section 7.1 explains how to calculate relocatable addresses. Section
7.2 explains how to calculate offsets. Section 7.3 describes how to
evaluate expressions.

7.1

CALCULATING RELOCATABLE ADDRESSES

If you know the absolute (relocated) address of a location and want to
determine what its relative address is, or what relocation register
contains the closest base address, use one of the forms of the a;nK
command.
If you specify both a, the absolute address, and n, a relocation
register,
in the a;nK command, ODT will calculate and display the
relative address, as follows:
_4000;2K =2,001460
Note that the equal sign is part of ODT's response, not
command that you enter.

part

the

If you omit n, ODT uses the relocation register whose contents
closest to (but less than) the absolute address specified.

are

If you omit a, ODT assumes the address of the last location opened.
You should omit the semicolon argument separator if you omit a.
To determine the absolute address of an open location or of the
last-opened
location, enter a dot
(current location indicator)
followed by an equal sign
(expression evaluation operator) , as
described in Section 7.3.2.

7=2

CALCULATING OFFSETS

The O (for "offset") command calculates and displays the PC-relative
offset and the branch displacement from one location to another.
There are two forms of this command. The ao command calculates the
offset from the currently open location to the location represented by
address expression a. This form of the command can only be used when
a location is open;
you type it on the same line as the displayed
contents of the open location.

7-1

PERFORMING CALCULATIONS
The a;kO command calculates the offset from the location represented
by address expression a to the location represented by address
expression k.
(In this case, k can have any of the address expression
forms described in Section 2.2.) This command can be entered either on
the same line as an open location or on a separate line,
in response
to the ODT prompt.
The O command (in either form) calculates either positive or negative
offsets. Negative offsets are displayed in two's complement form.
ODT displays the PC-relative offset and the branch displacement as
6-digit octal numbers.
The PC-relative offset is preceded by an
underscore and followed by a space;
the branch displacement is
preceded by a right arrow (>), as shown in the following example:
_1034/103421 10460

000010 >000004

A location that is open when you use the ao or a;kO commands remains
open after the offset and branch displacement are displayed. You can
perform another calculation, change the contents of the location, or
enter any ODT command that affects an open location.

7.3

EVALUATING EXPRESSIONS

You can evaluate expressions during your debugging session using the
techniques described in the following sections.
To evaluate an
expression while a location is open, enter the evaluation command on
the same line as the displayed contents of the location. ODT places
the results of its evaluation into the $Q register.
To replace the
contents of the open location, you enter Q or the value of the
expression.
You can also evaluate expressions when no location is
open by typing the evaluation command in response to the ODT prompt.

7.3.1

Equal Sign Operator

To evaluate an expression, enter the expression followed by the equal
sign
(=}.
The expression is converted to a 6-digit octal value,
placed in the $Q register, and displayed.
ODT truncates the octal
value of 16 bits when necessary.
Negative values are calculated, stored, and displayed in two's
complement form.
You can specify a negative value either in two's
complement form or with the minus sign.
You can perform
evaluated.
To
the values.
To
not recognize
expressions are

addition and subtraction within an expression to be
add values, include a plus sign {+) or a space between
subtract values, include a minus sign (-).
ODT does
parentheses or assign precedence to any operator;
evaluated left to right.

An address expression, in relative or absolute form,
part of an expression to be evaluated.

can

all

You can include in the expression the constant register indicator, the
quantity register indicator, or the current location indicator, as
described in the following sections.

7-2

PERFORMING CALCULATIONS
If you enter the equal sign without an expression to be evaluated, ODT
evaluates the null expression as zero and enters zeros in the $Q
register.
The following examples show the evaluation of expressions using
equal sign.
Relocation register $OR contains the value 370.
constant register contains the value 40.

the
The

0,0=000370
0,16=406
O,C=000430
0,16+16+2=0000426
16-370=177426
177777+16+16=000033
-1+16+16=000033
c 177777=000037
232323=032323

7.3.2

Current Location Indicator

The dot indicator (.) represents the address of the currently open
location. You use this symbol to include the address of the currently
open location as part or all of an expression to be evaluated.
The following example shows how
used:

the

current

location

indicator

320;1R
1,10/000000 .+10=000340

7.3.3

Constant Register Indicator

The C indicator specifies the 16-bit value contained in the constant
register, $C.
You can set this register to any value and use the
indicator in place of any a or k argument in an ODT command (as shown
in Section 2.2). You change the value of C by opening the $C register
as a word location and changing its contents.

7.3.4

Quantity Register Indicator

ODT stores the last value that it displayed in the quantity register,
$Q.
When you open a location, ODT stores that location's contents in
the $Q register.
If the location is a byte, the $Q register contains
that byte in its low-order byte and zeros in its high-order byte.
You can refer to this 16-bit value by using the quantity register
indicator Q. The quantity register indicator is especially useful for
changing the contents of open locations and for setting registers, as
shown in the following examples:
1342/173214 Q+lO
=/173224 IBru

$3/013624 Q;SR IBru
-5,20/013644

7-3

PERFORMING CALCULATIONS
7.3.S

Radix-SO Evaluation

To enter Radix-SO characters, you must know the numeric value of each
Radix-SO word.
A Radix-SO word, as explained in Section 4.10.2,
contains three Radix-SO characters. To determine the value of the
Radix-SO word, you enter the numeric equivalents of the Radix-SO
characters in that word, separated by asterisks, as an expression to
be evaluated.
Follow the expression with an equal sign, as shown in
Section 7.3.1.
ODT calculates a 6-digit octal value, places that
value in the $Q register, and displays it immediately after the equal
sign, as follows:
33*24*12=12S7S2
Note that you cannot evaluate Radix-SO characters in conjunction with
any
other evaluation operation
(addition, subtraction, location
calculation). You cannot use any other symbol
(C, Q,
.)
in the
expression to be evaluated.
If you specify the equivalents of only two Radix-SO characters,
fills the high byte of the word with zeros as necessary.

ODT

The Radix-SO character set includes all alphabetic and numeric
characters (A-Z, 0-9) plus three special characters: dollar sign {$),
dot {.), and space { ) • Table 7-1 contains the numeric equivalents of
all Radix-SO characters.
Tabl~ 7-1
Numeric Equivalents of Radix-SO Characters

Radix-SO
Character

Numeric
Equivalent

Radix-SO
Character

Numeric
Equivalent

Space

0
1
2

24
2S
26

A
B

c
D
E
F

H
I
J

K
L

M
N
0
p
Q

x
y
z

6
7
10
11
12
11
14
15
16
17
20
21
22
23

Unused
0
l

2
3
4
5
6
7
8
9

The following example shows how the asterisk is used in
with the Radix-SO operator (described in Section 4.10.2):
1054/0031Sl %AAA 1*3*5=003275 327S (BITl
%ACE

7-4

30
31
32
33
34
35
36
17
40
41
42
43
44
4S
46
47
conjunction

CHAPTER 8
ADDITIONAL DEBUGGING AIDS

The Task Builder on your system allows you to specify the debugger of
your choice to help you in program development. You should build only
one debugger into your task at a time;
if you want to switch from one
debugger to another, you must rebuild your task.
Section 8.1 shows how you specify other debuggers to the Task Builder
for the three environments described in Chapter 1. Section 8.2
describes the Trace program, a debugging aid available on your system.

8.1

ACCESSING OTHER DEBUGGING AIDS

The following sections show how to specify a debugger other than ODT
to be linked with your object module(s). The example in each section

shows a command line for linking the Trace debugging aid, described in
Section 8.2.
You can specify the file name of any debugger in place
of [l,l]TRACE.OBJ.

8.1.1

MCR Command Line

To link a debugger with your task using MCR, specify the name of the
debugger object module as input to the Task Builder.
Follow the
debugger object module name with the /DA switch, as in the following
example:
TKB>MYTASK=MYFILE,[l,l]TRACE/DA
The /DA swit~h identifies the file specified as a debugger. Since the
Task Builder assumes that the file type of input files is OBJ, you
need not specify the file type of the debugger object module.

8.1.2

DCL Command Line

To link a debugger into your task us1ng DCL, specify the name of the
debugger object module as an argument to the /DEBUG qualifier with the
LINK command, as in the following example:
>LINK/DEBUG:[l,l]TRACE/TASK:MYTASK MYFILE
Since DCL assumes that the file type of input files for the linker is
OBJ, you need not specify the file type of the debugger object module.

8-1

ADDITIONAL DEBUGGING AIDS
8.1.3

!AS PDS Command Line

To link a debugger with your task using IAS PDS, specify the name of
the debugger object module as an argument to the /DEBUG switch, as in
the following example:
PDS>LINK/DEBUG: [l,l]TRACE MYFILE

8.2

THE TRACE DEBUGGING PROGRAM

The Trace program is a debugging aid that can be used instead of or
along with ODT to provide information about the execution of a user
task. Trace is most appropriate for use with relatively simple tasks
or with sections of tasks.
Trace is an object module that you specify to the Task Builder when
you build your task, as described in Section 8.1.
It is located in
UFD [1,1] on the system disk, with the name TRACE.OBJ.
Trace is not an interactive program like ODT. When you run your task,
Trace is executed once and prints its listing on pseudo-device CL.
To
run Trace again, you must run your task again.

8.2.1

The Trace Listinq

A Trace listing contains two lines of information for each instruction
executed in the user's task. The first line is made up of five octal
words, representing the contents of the following registers:
1.

Current relative program counter (PC)

Current PC

Next PC

Processor Status Word

Directive Status Word

The relative PC is determined by subtracting a user-specified bias
value from the actual PC. Section 8.2.2 describes how you specify
this bias value.
The second line of the Trace listing contains
representing the contents of the following:
1-6.

RO through RS

Stack pointer

The top word of the stack

eight

octal

Example 8-1 is a sample Trace listing for part of a user task.

8-2

words

ADDITIONAL DEBUGGING AIDS
Example 8-1

Sample Trace Output

001714 003174 003176 170020 000001
002637 000120 000000 140200 000000

000000

001256

003074

001716 003176 003202 170024 000001
002637 000120 000000 140200 000000

000000

001256

003074

001722 003202 003074 170024 000001
002637 000120 000000 140200 000000

000000

001260

001614 003074 003100 170020 000001
002612 000120 000000 140200 000000

000000

001260

8.2.2

Bias Values and Ranges

You can use the GBLPAT Task Builder option to specify:
•

The bias value to be used in determining the relative PC

•

The range(s) of task locations to be traced

8.2.2.1 Specifying a Bias Value - To specify a
bias
value
for
relative PC calculation, enter an option line in the following format
in response to the Task Builder prompt:
GBLPAT=segname:.BIAS:value
segname
The name of the task's root segment.
value
The octal value to be subtracted from the actual PC to establish
relative PC.
(If a value is not specified, the initial stack
pointer is used.)

8.2.2.2 Specifying Ranges to be Traced - To specify up to four ranges
of locations for which execution should be traced, enter an option
line in the following format in response to the Task Builder prompt:
GBLPAT=segname:.RANGE:lowl:highl [ •••
segname
The name of the task's root segment.

8-3

:lown:highn]

ADDITIONAL DEBUGGING AIDS
lowl ••• lown
The low addresses, relative to the bias value, of
traced.

ranges

The high addresses, relative to the bias value, of ranges
traced.

highl ••• highn

There can be up to four ranges.
high address of each range.

You must specify both the low and the

8-4

APPENDIX A
ERROR DETECTION

ODT responds to errors in user input and to certain hardware-detected
errors that occur during task execution. This appendix describes
these errors, ODT's response to them, and suggested user action.

A.l

INPUT ERRORS

ODT uses the question mark (?) as an indicator that it has detected an
error in user input.
Arter displaying the question mark, ODT
generates a line feed and carriage return and prompts for another
command.
ODT responds with the question mark to
errors:

any

the

following

•

Reference to an address without an operator

•

Reference to an address outside the task's partition

•

Reference to a nonexistent register -- for example, $20

•

Reference to supervisor space by a nonprivileged user

•

Input of an illegal character

input

for example, 8 or 9

If you have typed an incorrect
input
string -- for
example,
contradictory arguments for the W command -- you may find that the
simplest course of action is to cancel the input string by typing an
illegal character. You cannot, however, erase a string once you have
entered the command -- the character W, in this case.
ODT does not tell you what error has caused it to display the question
mark.
However, an error sometimes causes ODT to return one of the
error codes listed in Section A.2, plus information on the location at
which the error occurred.
In some cases (for example, if you attempt a memory operation when $L
is greater than $H), ODT repeats its prompt but does not display a
question mark.

A-1

ERROR DETECTION
A.2

TASK IMAGE ERROR CODES

As described in Table 5-2, ODT has eight SST vector registers used to
contain pointers to error-handling routines. If ODT detects an error
condition, it activates the appropriate routine and displays an error
message.
This message has the form cc:k, where cc is a 2-character
error code and k is the location at which the error occurred.
ODT
displays the location as a relative address if there is a relocation
register containing a base address less than the absolute address of
the location.
The following examples are error messages from a debugging session:
MP:007414
OD:l,003507
The remainder of this chapter is an alphabetic list of ODT error
codes, their meanings, and suggested user action in response to these
codes.
BE
Explanation:
Breakpoint instruction executed at
unexpected
location.
The address of the breakpoint instruction does not
match the contents of any register, $OB through $7B.
User Action: Examine your code to determine why the unexpected
breakpoint occurred; then continue with the P command.

EM
Explanation: Invalid EMT instruction executed. Only EMT 377 and
EMT 376 (for a pr1v1~egea ~aSKJ are a~~owea oy the Executive for
execution of Executive Directives. Normally, vector address 30
is used for this trap sequence.
User Action~ If you want to use an EMT trap handler that you
have written, set SST vector register 5 ($5V) to the appropriate
vector address.
FP
Explanation:
Floating-point instruction error.
One of the
following has occurred: division by zero; illegal Floating Op
Code; flotation overflow or underflow; conversion failure.
User Action: Check your code for sequences that may have
one of these conditions.

caused

Explanation: Reserved or illegal instruction executed. The task
tried to execute a nonexistent instruction, or an EIS or FPP
instruction in a system with no EIS or FPP hardware.
User Action: Check your code for typographical errors or the use
of a nonexistent instruction.

A-2

ERROR DETECTION
IO
Explanation:
IOT instruction executed.
20 is used for this trap sequence.

Normally, vector address

User Action:
To change the handling of I/O traps, set SST vector
register 3 ($3V) to the appropriate vector address.
MP
Explanation:
Memory protection violation or illegal memory
reference.
The task tried to access a location outside of the
ranges mapped, or a location which it did not have the privilege
to access.
User Action:
Check your code for
typographical
errors that could lead to this condition.

programming

Explanation:
Odd address reference on word instruction.
The PC
contained an odd address when trying to access a word in memory.
Also, on some processors, execution of an illegal instruction.
Users Action:
Check your code for the use of a word instruction
when a byte instruction was intended (MOV instead of MOVB, for
example) or a typographical error in the address specification.
TE
Explanation:
T-bit exception.
The T-bit was set by some other
mechanism than a breakpoint or an S or P command.
This can occur
if bit 4 is set in a word that is interpreted as the PSW due to
its position on the stack.
User Action:

Check that the stack contains appropriate values.

TR
Explanation:
TRAP instruction executed.
address 34 is used for this trap sequence.

Normally,

vector

User Action:
To change the handling of TRAP instructions,
set
SST vector register 6 ($6V) to the appropriate vector address.

A-3

APPENDIX B
PROCESSOR STATUS WORD

The Processor Status Word (PS), stored at hardware location 777776,
contains information on the current status of the processor. The
information contained in this location includes:
•

The current and previous operational modes
(mapped system only)

the

processor

•

The current processor priority

•

An indicator which, when set, causes a trap upon completion of
the current instruction

•

Condition codes describing the results of the last instruction
executed

The format of the Processor Status Word is shown in Figure B-1.

14 13

---

PRIORITY

CARRY
...___ OVERFLOW
.....___ _ _ _ ZERO
.....___ _ _ _ _ _ NEGATIVE
....____ _ _ _ _ _ _ _ TRACE TRAP
~---------------------GEN REG SET
' - - - - - - - - - - - - - - - - - - - - - - - - - PREVIOUS MODE
. . . . _ _ _ - - - - - - - - - - - - - - - - - - - - - - - - - - - - C U R R E N T MODE

ZK-491-81

Figure B-1

Format of the Processor Status Word

Bits 15 and 14 indicate the current processor mode:
user mode
(11),
supervisor mode
(01), or kernel mode (00). Bits 13 and 12 indicate
the previous mode, that is, the mode the machine was in
(user,
supervisor~ or kernel) prior to the last interrupt or trap=
Bits 7 through 5 show the current priority of the central processor.
The central processor operates at any one of eight levels of priority
(0 through 7). When the central processor is operating at level 7
(the highest priority), an external device cannot interrupt it with a
request for service. The central processor must be operating at a
lower priority than the external device's request in order for the
interrupt to take effect.

B-1

PROCESSOR STATUS WORD

The trap bit (bit 4) can be set or cleared under program control.
When set, a processor trap will occur through location 14 upon
completion of the current user instruction, and a new Processor Status
Word will be loaded.
The trap
(T)
bit is especially useful in
debugging programs, since it provides an efficient means for stepping
through the task one instruction at a time.
CDT uses the T-bit to
execute instructions when you are stepping through your program with
the S command, described in Section 3.5.
The condition codes N, z, V, and C (bits 3 through O,
respectively)
indicate the result of the last central processor operation. These
bits are set as follows:
N=l,
Z=l,
V=l,
C=l,

if the result was negative.
if the result was zero.
if the operation resulted in an arithmetic overflow.
if the operation resulted in a carry from the
significant bit.

B-2

most

INDEX

A register, 2-6, 5-3
a symbol, 2-1 to 2-2
Abort,
task execution, 1-5
ABORT command, 1-5
Absolute,
address, 2-2
location, 2-5, 4-4
Address expression,
See Expression
Altering,
contents of location, 4-1
Argument,
register, 2-6, 5-3
separator, 2-5
Arithmetic operator,
See Operator
ASCII,
displaying, 4-6
operator, 2-7
~.sterisk (*), 2-5
At sign command (@), 2-5, 4-4

B command, 2-8, 3-1 to 3-2
B register, 2-6, 5-4
Backslash operator (\), 2-7,
4-2 to 4-3
Bias value, 2-3, 5-6
Trace program, 8-2
Branch,
location, 2-6, 4-5
offset, 7-2
Breakpoint, 3-1 to 3-3, 5-1
address register, 2-6, 3-2,
5-4
clear, 3-2
set, 3-1
instruction, 2-7, 5-4
proceed count, 2-7, 3-3, 5-4
removing, 2-8, 3-2
set, 3-1
Byte location,
displaying, 4-2 to 4-6
opening, 4-2 to 4-6
Byte mode,
operator,
ASCII, 2-7, 4-6
octal, 2-7, 4-2 to 4-3

C register, 2-6, 5-3, 7-3
indicator, 2-3, 2-8, 7-3

Index-1

Calculated location,
return from, 2-6, 4-6
Calculation1 7-1
offset, 7-1
relocatable,
address, 7-1
Changing,
See also Displaying
contents of location, 4-1
display mode; 4-3
Character, 2-3 to 2-4
illegal, 2-8
Circumflex command (A), 2-5,
4-4
Clear relocation register,
2-10
Closing,
location, 4-2
definition, 4-1
open location, 2-5, 4-2
Comma

(,),

2-4

Command,
ODT, 2-4
at sign (@), 2-5, 4-4
B, 2-8, 3-1 to 3-2
cancel, 2-8
c i r cum f 1 ex (
2- 5 , 4- 4
D, 2-8
E, 2-8, 6-3
equal sign {=}, 2-8, 7-2
F, 2-9, 6-4
G, 2-9, 3-2
I, 2-9
K, 2-9, 7-1
L, 2-9, 6-4
line feed, 2-5, 4-4
N, 2-10, 6-3
0, 2-10, 7-1
P, 2-10, 3-2 to 3-3
R, 2-10
relative branch location
(>), 2-6
return from calculated
location(<), 2-6
return key, 2-5, 4-2
s, 2-10, 3-3
U, 2-11
underscore ( ), 2-5, 4-5
v' 2-11
w, 2-11, 6-3
x, 1-4, 2-11
z' 2-11
Constant register, 2-6, 5-3,
7-3
indicator, 7-3
A

)

INDEX

Contents of location,
See Location
CONTINUE/DEBUG command,
IAS, 1-6
Continuing,
program execution, 3-2
CTRL/C,
ODT, 1-5
CTRL/U,
ODT, 2-8
Current location,
indicator ( .) , 2-3, 2-5, 7-3
Cursor,
ODT, 4-1

D command, 2-8
D register, 2-7, 5-4, 6-2
Data space, 7-2
command, 2-8
access~ 2-8
enable, 1-3
DCL,
linking,
debugger, 8-1
ODT, 1-3
ODTID, 1-4

supervisor libraries; 1-4
DEBUG command,
RSX-llM-PLUS, 1-5
Debugger,
specifying to Task Builder,
8-1
Debugging,
privileged task, 1-4
session,
abort, 1-5
begin, 1-4, 3-1
end, 1-4
interrupting of, 1-5, 3-2
resuming, 1-5 to 1-6
supervisor mode, 1-4
Device control,
LUN register, 2-7, 5-4, 6-2
Directive status_ word,
register, 2-6, 5-3
Display,
mode, 4-1, 4-3, 4-6, 6-5
Di splaying,
byte location, 4-2 to 4-6
location, 4-1
word location, 4-2 to 4-6
Do t ( . ) , 2 - 5 , 7 - 3

E command, 2-8, 6-3
E register, 2-7, 5-4

Index-2

Equal sign (=}, 2-8, 7-2
Error,
detection, A-1
input, A-1
task image, A-2
Evaluating expression,
See Expression
Examine location,
See Displaying
Exit,
ODT, 1-4
Exit command,
ODT, 2-11
Expression, 2-3
evaluating, 2-3, 7-2
format, 2-2
Radix-50, 7-4

F command, 2-9, 6-4
F register, 2-6, 5-3
Fill command, 2-9, 6-4
Fill memory, 6-4
Fixed task,
ODT, 5-7
Format,
memory listing, 6-5
register: ?-6: 5-3
Trace listing, 8-2

G command, 2-9, 3-2
G register, 2-7, 5-4
GBLPAT,
See TKB
General register, 5-2
Go command, 2-9, 3-2

H register, 2-6, 5-3

I command, 2-9
I register, 2-7, 5-4
IAS,
linking,
debugger, 8-2
ODT, 1-3
Indicator,
See Register indicator
Instruction space, 3-2, 7-2
command,
access, 2-9
enable, 1-3
Internal register, 5-2

INDEX

Invoking,
ODT, 1-4, 5-1

N command, 2-10, 6-3
n symbol, 2-1 to 2-2
Negative offset, 7-2
Next sequential location, 4-4

K command, 2-9, 7-1
k symbol, 2-1, 2-3

L command, 2-9, 6-4
L register, 2-6, 5-3
Limit register, 2-6, 5-3
Line feed command, 2-5, 4-4
LINK command,
DCL, 1-3 to 1-4, 8-1
Linking,
ODT, 1-2
DCL, 1-3
MCR, 1-2
PDS, 1-3
RSX-llM-PLUS feature, 1-3
List command, 2-9, 6-4
Li sting,
device,
specifying, 6-2, 6-5
format,
memory, 6-5
Trace program, 8-2
Location,
altering, 4-1
closing, 4-2
displaying, 4-1 to 4-3
Location indicator,
See Register indicator

M register, 2-6, 5-3
m symbol, 2-1
Mask register, 2-6, 5-3
MCR,
linking,
debugger, 8-1
ODT I 1-2
ODTID I 1-3
supervisor libraries, 1-4
Mi:=>mr.rv
_
.l ,

.&.&-&1.1.-

fill command, 2-9, 6-4
limit register, 2-6, 5-3,
6-1
list command, 2-9, 6-4
listing format, 6-5
search, 6-3
search command, 2-8, 2-10 to
2-11
Message,
invocation, 1-4
Minus sign (-), 2-3 to 2-4

Index-3

0 command, 2-10, 7-1
Octal operator, 2-7, 4-2 to
4-3
ODT,
overview, 1-1
ODTID module, 1-3
Offset, 2-3, 7-1
branch, 7-2
calculation, 2-10, 7-1
negative, 7-2
PC-relative, 7-2
Opening,
absolute location, 2-5, 4-4
byte location, 4-2 to 4-6
location,
definition, 4-1
PC-relative location, 2-5,
4-5
preceding location, 2-5, 4-4
relative branch location,
2-6, 4-5
sequential location, 2-5,
4-4
word location, 4-2 to 4-6
Operating system,
return to, 2-11
Operator, 2-3 to 2-4, 2-7, 4-2
ASCII (/) I 2-7
backslash {\), 2-7, 4-2 to
4-3
byte mode,
ASCII, 2-7
octal, 2-7, 4-2 to 4-3
comma ( , ) , 2-4
equal sign {=), 2-8, 7-2
minus sign (-), 2-3 to 2-4
plus sign (+), 2-3 to 2-4
Rad ix - 5 0 ( %) , 2- 7
slash (/), 4-2 to 4-3
word mode,
ASCII; 2-7
octal, 2-7, 4-2 to 4-3
" {operator), 2-7, 4-6
% (operator) , 2-7, 4-7
{operator), 2-7, 4-6

P command, 2-10, 3-2 to 3-3
PC-relative,
location, 2-5, 4-5
offset, 2-10, 7-2

INDEX

PDS,
linking,
debugger, 8-2
ODT, 1-3
Plus sign {+) , 2-3 to 2-4
Preceding location,
opening, 4-4
Proceed,
command, 2-10, 3-2 to 3-3
count, 2-7, 3-3
Processor status word, B-1
register, 2-6, 5-3
Program execution,
continuing, 3-2
resuming, 3-2
Prompt,
ODT, 1-4

Q register, 2-6, 4-1, 5-3,
7-2 to 7-3
indicator, 2-3, 2-10, 7-3
Quantity register, 2-6, 5-3,
7-3
indicator, 2-10, 7-3
Question mark {?), A-1

R command, 2-10
R register, 2-7, 5-5 to 5-6
Radix-50,
character set, 7-4
displaying, 4-6 to 4-7
evaluation, 7-4
operator {%), 2-7, 4-6 to
4-7
separator (*), 2-5, 7-4
Range,
Trace program, 8-2
Reentry,
vector register, 5-3
Reference,
search, 2-8, 6-3
Register, 2-6, 5-1
A, 2-6, 5-3, 6-2
argument, 6-2
B, 2-6, 5-4
breakpoint,
address, 2-6, 3-1 to 3-2,
5-4
instruction, 5-4
proceed count, 3-3, 5-4
c, 2-6, 5-3
constant, 2-6
D, 2-7, 5-4, 6-2
device LUN, 2-7, 5-4, 6-2

Index-4

Register (Cont.)
directive status word, 2-6,
5-3
E, 2-7, 5-4
F, 2-6, 5-3
format, 2-6
G, 2-7, 5-4
general, 5-2
H, 2-6, 5-3, 6-1
high memory limit, 2-6, 6-1
I, 2-7, 5-4
indicator, 2-8
instruction, 2-7
internal, 5-2
L, 2-6, 5-3, 6-1
low memory limit, 2-6, 6-1
M, 2-6, 5-3, 6-2
memory limit, 5-3
memory operation, 6-1
proceed count, 2-7
processor status, 2-6, 5-3
Q, 2-6, 4-1, 5-3, 7-2
quantity, 2-6, 5-3
R, 2-7, 5-5 to 5-6
reentry vector, 2-6, 5-3,
5-7
relocation, 2-7, 5-5 to 5-6
s, 2-6, 5-3
search arqument, 2-6, 6-2
search limit, 5-3
search mask, 2-6, 6-2
SST stack content, 2-7, 5-4
SST vector, 2-7, 5-5
v, 2-7, 5-5
w, 2-6, 5-3
x, 2-6, 5-3, 5-7
Register indicator, 2-3, 7-3
C register, 2-3
current location ( .) , 2-3,
2-5
Q register, 2-3
Register set, 5-4
Relative,
address, 2-2
branch location, 2-6, 4-5
Relocatable,
address, 2-2, 5-6
calculating, 2-9, 7-1
Relocation,
register, 2-2, 2-7, 5-5 to
5-6
clear, 2-10, 5-6
set, 2-10, 5-6
Reopen last location, 4-3
Resuming,
program execution, 3-2
task execution, 1-5, 3-2
Return key command, 2-5, 4-2

INDEX

S command, 2-10, 3-3
S register, 2-6, 5-3
Search,
argument register, 2-6, 5-3,
6-2
command, 6-3
limit register, 2-6, 5-3,
6-1
mask register, 2-6, 5-3, 6-2
memory, 2-8, 2-10, 6-3
word or byte, 2-11, 6-3
Search command, 2-11
Semicolon (;) , 2-5
Separator,
dot(.), 2-5
Radix-50 (*), 2-5
semicolon (;) , 2-5
Slash operator (/), 2-7,
4-2 to 4-3
SST stack content,
register, 2-7, 5-4
SST vector,
handling, 2-11
register, 2-7, 5-5
Step command, 2-10, 3-3
Supervisor libraries, 1-4
Supervisor mode, 1-4, 3-2
command, 2-11
debugging, 1-4
install,
READ/WRITE, 1-4
set, 2-11
$ symbol, 2-6, 5-1
? symbol, A-1

Task,
privileged,
debugging, 1-4
Task Builder,
See TKB
Task execution,
abort, 1-5
begin, 2-9, 3-2
continuing, 2-10, 3-2
resuming, 1-5 to 1-6, 3-2
RSX-llM-PLUS feature, 2-9
Task name, 5-1
TE trap, 1-5 to 1-6
TKB,
GBLPAT option, 8-2
linking,

TKB {Cont.)
ODT, 1-2
ODTID, 1-3
supervisor libraries, 1-4
specifying,
debugger, 8-1
UNITS option, 6-2
Trace program, 8-2
listing,
format, 8-2
Trap, 1-5 to 1-6, 2-11, 5-5,
A-2
handling, 2-11, 5-5

U command, 2-11
Underscore command (_), 2-5,
4-5
UNITS Task Builder option, 6-2
User mode, 1-4, 3-2
command, 2-11
set, 2-11

V command, 2-11
V register, 2-7, 5-5
Variable, 2-1
Vector register, 5-7
reentry, 2-6

W command, 2-11, 6-3
W register, 2-6, 5-3
Word location,
displaying, 4-2 to 4-6
opening, 4-2 to 4-6
Word mode,
operator,
ASCII, 2-7, 4-6
octal, 2-7, 4-2 to 4-3
Radix-50, 2-7

X command, 1-4, 2-11
X register, 2-6, 5-3, 5-7
x symbol, 2-1

Z command, 2-11

Index-5

IAS/RSX-11
ODT Reference Manual
AA-M507A-TC
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