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July 1984

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Document:	AA-M393B-TC MicroPower Pascal 1.3 Debugger Users Guide 198307
Order Number:	AA-M393A-TC
Revision:	0
Pages:	145
Original Filename:	AA-M393B-TC_MicroPower_Pascal_1.3_Debugger_Users_Guide_198307.pdf

OCR Text

Micro Power/Pascal
Debugger User's Guide
TM

AA-M393B-TC

Micro Power/Pascal
Debugger User's Guide
TM

AA-M3938-TC

July 1983

This manual describes how to use the MicroPower/Pascal symbolic debugger, PASDBG. The manual describes the hardware and software
required for a PASDBG application, explains the commands used in
PASDBG, and presents examples.
This manual supersedes the Micro Power/ Pascal Debugger User's
Guide, AA-M393A-TC.
This manual contains Update Notice 1, AD-M393B-T1 .
Operating System:

Software:

RT-11 Version 5.0
RSX-11 M Version 4.1
RSX-11 M-PLUS Version 2.1
VAX/VMS Version 3.4

MicroPower/Pascal Version 1.5

To order additional documents from within DIGITAL, contact the Software Distribution
Center, Northboro, Massachusetts 01532.
To order additional documents from outside DIGITAL, refer to the instructions at the back
of this document.

digital equipment corporation . maynard, massachusetts

First Printing, February 1982
Updated, June 1982
Updated, October 1982
Updated, February 1983
Revised, July 1983
Updated, February 1984

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 or its affiliated companies.

All Rights Reserved.
Printed in U.S.A.
A postage-paid READER'S COMMENTS form is included on the last page of this
document. Your comments will assist us in preparing future documentation.
The following are trademarks of Digital Equipment Corporation:

mnmnomo™
DEC
DECmate
DECsystem-10
DECSYSTEM-20
DEC US
DECwriter
DIBOL
FALCON

MASSBUS
MICRO-PDP-11
MicroPower/Pascal
PDP
PIOS

Professional
Rainbow
RSTS

M27300

RSX
UNIBUS
VAX
VMS
VT
Work Processor

UPDATE NOTICE 1

Micro Power/Pascal
Debugger User's Guide
TM

AD-M393B-T1

February 1984
NEW AND CHANGED INFORMATION
This update contains changes and additions to the MicroPower/Pasca/
Debugger User's Guide, AA-M393B-TC.

digital equipment corporation . maynard, massachusetts

INSTRUCTIONS
The enclosed pages are replacements for or additions to current pages of the
MicroPower/Pasca/ Debugger User's Guide. On replacement pages, changes and additions are
indicated by vertical bars (I ); deletions are indicated by bullets(•).
Keep this notice in your manual to maintain an up-to-date record of changes.
© Digital Equipment Corporation 1984.
All Rights Reserved.
Printed in U.S.A.

Old page

New page

Title/Copyright
iii/iv to vii/viii
1-1/1-2 to 1-19/blank
2-:-1/2-2
2-9/2-10

Title/Copyright
iii/iv to vii/viii
1-1/1-2 to 1-21/blank
2-1/2-2
2-9/2-10
2-10.1 /blank
2-17/2-18
2-19/blank
3-1/3-2
3-3/3-4
3-9/3-1 o to 3-15/3-16
3-16.1 /blank
3-17/3-18
3-19/3-20
3-20.1 /blank
3-2713-28 to 3--33/3--34
3-41/3-42
3-43/3-44
3-49/3-50
3-69/3--70
3-70.1 /blank
A-1/A-2
lndex-1 /lndex-2
lndex-3/lndex-4
Reader's Comments/Mailer

2-17/2-18
2-19/blank
3--1/3-2
3-3/3-4
3--9/3-1 o to 3-15/3-16
3-17/3--18
3-19/3--20
3-2713-28 to 3-33/3-34
3-41/3-42
3-43/3-44
3-49/3-50
3-69/3--70
A-1/A-2
lndex-1 /lndex-2
lndex-3/lndex-4
Reader's Comments/Mailer

CONTENTS

Page
PREFACE
CHAPTER

vii
1

GETTING STARTED

1-1

1.1

1-1
1-1
1-2
1-2
1-2
1-2
1-2
1-3
1-4
1-6
1-6

1.2.3.3
1.2.3.4
1.2.3.5
1. 3
1. 4
1. 5

DEBUGGER FEATURES
Host/Target Communication
Commands
Symbolic Debugging
Process Control variables and Structures
Execution Error Restart
THE DEBUGGER ENVIRONMENT
Required Hardware
Required Software
Host/Target Communication Problems
No Target Communication
No Communication with FALCON or FALCON-PLUS
Target
Nonstandard Vector and CSR on RT-11 Host
Target System Halts on Load Command
TD Logical Device Access on RSX or VMS Host
BUILD PROCEDURE FOR DEBUGGING
BEGINNING A DEBUGGING SESSION
SAMPLE DEBUGGING SESSION

1-7
1-7
1-7
1-7
1-8
1-12
1-16

DEBUGGING TECHNIQUES

2-1

2.1
2 .1.1
2 .1. 2
2.1.2.1
2.1.2.2
2 .1. 3
2.1.3.1
2.1.3.2
2.1.3.3
2.1.3.4
2 .1. 4
2.1.4.1
2.1.4.2
2 .1. 5
2.2
2.2.1
2.2.2
2.2.3
2.2.4
2.3
2.3.l
2.3.2
2.3.3

GENERAL DEBUGGING
Loading the Application Program
Controlling Symbol and Address Resolution
PROGRAM, SCOPE, and SET PHYSICAL
PROCESS
Controlling Program Execution
Starting and Stopping Execution
BREAK, TRACE, and WATCH
Invocation Chain Display
Reinitializing and Restarting
Examining and Modifying Data
Variable Modification and Display
Structure Display
General Debugging Aids
REAL-TIME DEBUGGING
Typed Data Structure Display
State Queue Display
Exception-Handling Display
Real-Time Debugging Aids
DEBUGGING HINTS
Real-Time Errors
Critical Sections
Race Conditions

2-1
2-1
2-2
2-2
2-5
2-5
2-6

l . l. l

1.1. 2
1. 1. 3
1.1. 4
1.1. 5
1. 2
1. 2.1
1. 2. 2
1. 2. 3
1.2.3~1

1.2.3.2

CHAPTER

Version 1.5, February 1984

iii

2-7
2-8
2-8
2-8
2-8
2-9
2-9
2-10
2-10.1
2-12
2-13
2-13
2-14
2-14
2-14
2-16

2.3.4
2.3.5
2.3.6
2.3.7
2.3.8

STEP and WATCH Commands
SET WATCH with Local variables
Micro-ODT (uODT) Mode
Fatal Exceptions
Debugging FALCON or FALCON-PLUS
Applications
Debugging KXTll-C Arbiter/Slave Protocol
Transactions

2.3.9
CHAPTER

2-16
2-17
2-17
2-18
2-19
2-19

COMMAND REFERENCE

3-1

3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
3 .10
3.a
3 .11
3.12
3.13
3.14
3.15
3.16
3.17
3.18
3.19
3.20
3.21
3.22
3.23
3.24
3.25
3.26
3.27
3.28
3.29
3.30
3.31
3.32
3.33
3.34
3.35
3.36
3.37
3.38
3.39
3.40
3. 41
3.42
3.43
3.44
3.45
3.46
3.47
3.48
3.49
3. 50
3.b
3.51

CANCEL BREAK
CANCEL PROCESS
CANCEL SCOPE
CANCEL STEP
CANCEL TRACE
CANCEL WATCH
CLOSE
CTRL/C
CTRL/O
CTRL/Y
DEPOS.iT
EXAMINE
EXIT
GO
HALT
HELP
!NIT
LOAD
LOG
SET BREAK
SET ODT
SET PHYSICAL
SET PROCESS
SET PROGRAM
SET SCOPE
SET STEP
SET TRACE
SET WATCH
SHOW BREAK
SHOW CALLS
SHOW EXCEPT ION
SHOW EXCEPTION GROUPS
SHOW FREE PACKETS
SHOW FREE STRUCTURES
SHOW INACTIVE QUEUE
SHOW NAMES
SHOW PACKET QUEUE
SHOW PCB
SHOW PROCESS
SHOW READY/ACTIVE QUEUE
SHOW READY/SUSPENDED QUEUE
SHOW RING BUFFER
SHOW RUN QUEUE
SHOW SCOPE
SHOW SEMAPHORE
SHOW STEP
SHOW STRUCTURE
SHOW TARGET
SHOW TRACE
SHOW WATCH
SPAWN
STEP

3-2
3-4
3-6
3-7
3-8
3-9
3-11
3-13
3-14
3-15
3-16
3-16.1
3-19
3-22
3-23
3-24
3-25
3-26
3-28

Version 1.5, February 1984

3-3~

3-31
3-33
3-34
3-35
3-37
3-38
3-40
3-41
3-43
3-45
3-46
3-47
3-48
3-49
3-50
3-51
3-52
3-53
3-54
3-56
3-58
3-59
3-60
3-61
3-62
3-63
3-64
3-65
3-67
3-68
3-69
3-70
3-70.1

APPENDIX
A.l
A. l. 1

A .1. 2
A.2
A.2.1
A.2.2

TARGET INTERFACE SPECIFICATIONS

A-1

PROTOCOLS
Inquiry/Response Protocol
Asynchronous Message Protocol
MESSAGES
Inquiry/Response Messages
Asynchronous Messages

A-1
A-1
A-2
A-2
A-2
A-6

INDEX

Index-1

FIGURES
FIGURE

1-1
2-1
2-2

PASDBG Hardware Configuration
Program Example Using Flags for Process
Control
Program Example Using Semaphores for
Process Control

1-3
2-14
2-15

TABLES
TABLE

1-1

Debugger Commands

version 1.5, February 1984

1-13

PREFACE

This manual describes the features and use of the MicroPower/Pascal
symbolic debugger, PASDBG.
The manual is based on the assumption that
you are familiar with either Pascal or MACR0-11.
In addition,
it is
assumed that you have read the MicroPower/Pascal installation guioe
for your host system, Chapter 3 of the MicroPower/Pascal system user's
guide for your host system, and Chapter 2 of the MicroPower/Pascal
Runtime Services Manual.
The installation guide describes host and
target hardware configuration requirements for debugging; Chapter 3
of the system user's guide describes the application build procedure;
and Chapter 2 of the MicroPower/Pascal Runtime Services Manual
describes data structures that are referenced in this manual.
Chapter Summary

Chapter 1 provides a short description of debugger features and
discusses the hardware and software requirements of the debugger. The
chapter also outlines the build procedure for debugging, describes the
format for debugger commands, and explains how to begin and end a
debugging session. The chapter ends with a sample debugging session.
Chapter 2 describes the debugger commands and explains how to use the
debugger to load your application program, reference symbol names and
addresses, control program execution, examine and modify data, and
examine real-time process control structures.
The chapter also
provides hints for dealing with problems and special situations that
can occur while you are debugging.
Chapter 3 provides information about debugger
command
format,
qualifiers, and parameters for quick reference.
Sections are ordered
alphabetically by command name.
The Appendix describes the protocols that govern communication between
the debugger in the host system and the Debugger Service Module (DSM)
in the target system. These protocols are transparent to the user.
Associated Documents

The following software documentation is required
for
complete
reference purposes.
Refer to the documentation list for your host
operating system.
•

RT-11 Host:

MicroPower/Pascal-RT documentation set. A complete list
of documents is contained in the MicroPower/Pascal-RT
Documentati~n Directory (Order No.
AA-W966B-TC).

Version 1.5, February 1984

vii

•

RT-11 VS host operating system documentation set.
A
subset of the RT-11 VS documentation set is contained in
the MicroPower/Pascal-RT documentation set. No additional
RT-11 documentation is required for MicroPower/Pascal-RT
application software development.

RSX-llM/M-PLUS Host:

•

MicroPower/Pascal-RSX documentation set. A complete list
of documents is contained in the MicroPower/Pascal-RSX
Installation Guide (Order No. AA-AK10A-TC).

RSX-llM/M-PLUS h~st operating
Re~er
to the documentation
operating system.

system documentation set.
set supplied with your host

VAX/VMS Host:
1.

MicroPower/Pascal-VMS documentation set. A complete list
of documents is contained in the MicroPower/Pascal-VMS
Installation Guide (Order No. AA-AI16A-TE).

VAX/VMS host operating system documentation set. Refer to
the documentation set supplied with your host operating
system.

Document Conventions
This document uses the following conventions:
Convention

Meaning

[

Square brackets indicate
item is optional.

]

{ }

that

the

enclosed

Braces enclose lists from which
is to be chosen.

one

element

A horizontal ellipsis indicates
preceding item(s) can be repeated.

that

the

A vertical ellipsis indicates that not all
the statements in an example or figure are
shown.
PASDBG>load test

In examples, user input is shown in
type.

boldface

CTRL/x

The symbol CTRL/x means that you should type
a key (represented by x) while holding down
the key labeled CTRL.

<RET>

The symbol <RET> means that you should
the RETURN key.

press

Numbers are in decimal radix unless otherwise specified.
Symbol conventions for the operator symbols used in debugger
are listed at the beginning of Chapter 3.

Version 1.5, February 1984

viii

commands

CHAPTER 1

GETTING STARTED

This chapter introduces the MicroPower/Pascal interactive debugger,
PASDBG, and provides the information you need to run it.
Section 1.1
lists the debugger features.
Section 1.2 describes the hardware and
software required to run PASDBG.
Section 1.3 outlines the build
procedure for debugging.
Section 1.4 explains how to invoke and issue
commands to the debugger.
Section 1.5 shows a sample debugging
session.

1.1

DEBUGGER FEATURES

The PASDBG symbolic debugger provides the following features:

1.1.1

•

A communication link between the host computer and the target
system,
allowing you to down-line load and control an
application program from a terminal on the host computer

•

Commands and qualifiers that allow you to control and
an executing program

•

Access to the symbol table generated by the Pascal compiler,
providing symbolic (Pascal language) referencing and variable
access

•

Access to process control variables and structures

•

A mechanism for user control after an execution error

examine

Host/Target Communication

PASDBG resides as a running program on the development, or host,
system.
You issue commands to PASDBG from a terminal on the host
system. Your application program restdes on the application, or
target, system and contains a module called the debugger service
module (DSM). You add the DSM to your application program by using
the DEBUG = YES option in your configuration file.
A serial line
connects the host and target systems, providing a communication path
between PASDBG and the DSM.
This serial line is used to down-line
load the application for debugging and to control the application.
(Refer to Section 1.2 and the LOAD command in Chapter 3 for details on
down-line loading with PASDBG.) No terminal is required on the target
system.

Version 1.5, February 1984

1-1

GETTING STARTED
1.1.2

Commands

The debugger commands allow you to control execution of
your
MicroPower/Pascal program and to examine and modify your program and
data.
Section 1.4 lists the debugger commands, and Chapters 2 and 3
describe the commands in detail.

1.1.3

Symbolic Debugging

The Pascal compiler produces a table of symbols that PASDBG can
reference during a debugging session. You generate these symbols by
using the /D switch for those programs or modules that you wish to
debug.
The symbol table provides information on all variables,
structured variables, pointer variables, user-defined types, labels,
procedures, functions, main programs, and modules.
If the Pascal
program uses descriptor variables, the symbol table also contains
information about semaphores and ring buffers.

1.1.4

Process Control Variables and Structures

PASDBG permits access to process control variables and structures.
For example, you can examine semaphore states, process state queues,
and blocked and active processes. Chapter 2 discusses process control
variables in more detail.

1.1.5

Execution Error Restart

PASDBG allows you to examine or restart a program after the occurrence
of a runtime error.
If necessary, PASDBG can down-line load a new
copy of the application program. PASDBG can also restart execution
from the point where the program failed.
If the target system
crashes, PASDBG allows you to run the target Micro-CDT from the host
terminal.
Refer to Section 2.3.6 and the SET ODT command in Chapter 3
for more details on ODT mode.

1.2

THE DEBUGGER ENVIRONMENT

This section describes the hardware and software you need to run
PASDBG.
This section also tells you how to correct host/target
communication problems that you may encounter when you invoke the
debugger or down-line load your application program.
NOTE
The hardware
descriptions
in
this
section
are
categorical
and
not
host-specific.
For
detailed,
host-specific descriptions of the host
and target hardware requirements for
debugging,
see the MicroPower/Pascal
installation guide for your host system.

Version 1.5, February 1984

1-2

GETTING STARTED

1.2.1

Required Hardware

The system configuration for
following hardware:

debugging

must

contain

least

the

management

and

line

one for the terminal

and

Host System
•

PDP-11 or VAX-11 processor with
clock

memory

•

Two asynchronous serial-line ports:
the other for the target system

•

A file-structured storage device

•

64K words of memory for RT-11, 124K words for RSX-llM, 256K
words for RSX-llM-PLUS, or, for VAX/VMS, sufficient memory as
described in the MicroPower/Pascal-VMS Vl.5 Software Product
Description

Target System
•

PDP-11 processor

•

Sufficient memory to contain the application program, 4K bytes
of RAM minimum

•

One serial-line port for the host system

•

Other peripheral
program

devices

required

the

application

Figure 1-1 illustrates the configuration required for down-line
loading and debugging a target system from an RT-11 host system. For
RSX-llM/M-PLUS and VAX/VMS host systems, the configuration
for
debugging each target system connected to the host is conceptually
similar to that shown below. The hardware differences are described
in the MicroPower/Pascal installation guides for the respective host
systems.

Console
terminal
HOST SYSTEM
Any PDP-11 with:
memory management
128KB memory
line clock

serial lines
TARGET SYSTEM

Any PDP-11 of the
LSl-11 family

csr= 177560
vector= 60

Figure 1-1

PASDBG Hardware Configuration

version 1.5, February 1984

1-3

ML-101-81

GETTING STARTED

PASDBG uses a serial line to communicate between the host and target
systems.
PASDBG down~line loads your application program -- refer to
the LOAD command in Chapter 3 -- and controls the application through
this serial line. You must configure your host and target hardware in
the following way so that PASDBG can use the serial-line link:
1.

Connect the host/target serial line to
console line.

the

target

system's

Set the control status register of the target
serial-line port to 177560 and its vector to 60.

system's

Set the target system's console line to halt the processor on
a BREAK command.
NOTE

1.2.2

Do not attempt to use
debug
programs
that
read-only memory (ROM) •

PASDBG
reside

Do not use the console serial
for the application program.

to
in
line

Required Software

You need the following programs, files, and libraries to run PASDBG.
Host System

•

RT-11, RSX-llM/M-PLUS, or VMS operating system

•

The .MIM file created during the application
(application program master copy)

build

procedure

•

The .DBG file created during the application
(required for symbolic debugging)

build

procedure

•

PASDBG.SAV (RT-11), MPPPDB.TSK (RSX-llM/M-PLUS), or PASDBG.EXE
(VMS)

PASDBG.HLP

•

TDBOTU.BOT or TDBOTM.BOT

•

TDX.SYS (RT-11 host

•

MPPBRK.TSK (RSX-llM/M-PLUS host only;
default on MP: [l,54])

only~

must reside on SY:)
resides by installation

The .DBG file created during the application build procedure contains
information that PASDBG uses for access to symbols and kernel
information. You specify use of the .DBG file with the LOAD command
(refer to Chapter 3). The .DBG file is not required for running the
debugger, but it is needed for access to symbols in the user program
and to kernel symbols. Symbol- or kernel-specific commands, such as
EXAMINE FOO and SHOW RUN QUEUE, do not work without the .OBG file.

Version 1.5, February 1984

1-4

GETTING STARTED

TDBOTU.BOT and TDBOTM.BOT are used as bootstraps for the PASDGB LOAD
command.
When the LOAD command is used, it examines the .MIM file to
determine whether the file is mapped.
If the .MIM file is mapped,
PASDBG will use TDBOTM.BOT as the bootstrap.
If the .MIM file is not
mapped, PASDBG will use TDBOTU.BOT as the bootstrap.
The PASDBG .SAV/.TSK/.EXE and
.HLP files and the appropriate TD
bootstrap must reside on a particular installation-defined logical
device for each type of host system.
The installation default for
each host is as follows:
Host

Logical Device

RT-11

LB:

RSX-llM/M-PLUS

MP: [1,54] for MPPPDB.TSK
MPl: [1,1] for PASDBG.HLP and TD bootstrap

VAX/VMS

MICROPOWER$L IB:

or SY:

TDX.SYS is the load module for the standard RT-11 serial-line (TD)
handler.
The TD handler controls the serial line connecting the host
and target systems and is used by PASDBG-RT to communicate between
host and target.
PASDBG-RT requires that the TD handler be loaded;
if it is not, PASDBG-RT loads it automatically.
NOTE
PASDBG-RSX uses the standard
RSX-11
terminal driver to handle the serial
line through which it communicates with
the
target
system.
Similarly,
PASDBG-VMS
uses
the
standard
VMS
terminal
driver
to
handle
its
host/target serial line. Software setup
requirements for the serial line are
determined by the host operating system
and differ somewhat between PASDBG-RSX
and PASDBG-VMS.
In both cases, however,
you must assign the logical device name
TD:
to the line connected to your
target system before invoking PASDBG,
and the line must be set to a speed
matching that of the target's console
terminal port. See Chapter 10 of the
MicroPower/Pascal-RSX/VMS System User's
Guide for details on host/target line
setup for RSX and VMS hosts.
MPPBRK.TSK is a slave task that PASDBG-RSX uses to perform privileged
commands to the device TD.
The debugger requires that MPPBRK.TSK be
installed with the name ... BRK on the host system. When invoked, the
debugger checks for
••. BRK and issues an error message if it is not
installed. The ..• BRK task is used for such operations as setting TD
line characteristics and sending BREAK signals down the TD line to
halt the target for loading or for SET ODT commands.
Only the
debugger may invoke ••• BRK.

Version 1.5, February 1984

1-5

GETTING STARTED
Application System
•

The .MIM file created during the application
(the application program)

build

procedure

•

The debugger service module (DSM)
program

the

application

as part of

The PASDBG debugger has two parts:
the debugger service module
(DSM)
and the PASDBG program.
The PASDBG program resides on the host system
and runs under the host operating system.
The DSM resides on the
application system as part of the application program.
To use the debugger, you run the PASDBG program and give it commands.
PASDBG interprets each command you give it and issues a command to the
DSM over the serial-line link between the processors.
The DSM,
in
turn, answers PASDBG over the same line.
PASDBG maintains most of the
information required for debugging the program, thus minimizing the
space required for the DSM on the application system.

1.2.3

Host/Target Communication Problems

This section tells you how to correct host/target communication
problems you may encounter when you invoke the debugger or down-line
load your application program.

1.2.3.1 No Target Communication - Under certain conditions,
PASDBG
may not be able to establish communication between the host system and
the target system.
(Communication is defined as the target system's
responding to a simulated Break sent by the host system by halting and
executing console ODT microcode.)
If
communication
cannot
be
established, PASDBG displays the following error message:
?PASDBG-E-NOCOMM,
cables)

target

communication

(check

power

and

target

systems

If this error message is displayed, make sure that:
•

The target system is powered up

•

The serial
connected

host

and

•

The serial line baud rates are equal
target systems

host

and

•

The communications line is attached to the console serial
port of the target system

I/O

•

The target system hardware is configured to respond
by entering ODT

•

(RT-11 host only:) The TD handler is set for the correct
and interrupt vector values -- see Section 1.2.3.3

•

(RSX-llM/M-PLUS or VAX/VMS host only:)
The system-dependent
parameters of the host/target link are set up as described in
Chapter HJ of the MicroPower/Pascal-RSX/VMS System User's
Guide

line

Version 1.5, February 1984

between

the

1-6

both

the

Break
CSR

GETTING STARTED
1.2.3.2 No Communication with FALCON or FALCON-PLUS Target - If your
target system is an SBC-11/21 and is running at processor priority 7,
you must turn the target off and on again to establish communication.
PASDBG cannot halt an SBC-11/21 if the processor priority is 7.
If your target system is an SBC-11/21 and if the value specified for
the configuration file KXTll macro baud rate parameter is not the same
as the line rate, the target system will load correctly but will fail
with the "No target communication" message once the application
program initializes. You can correct this problem by changing the
KXTll macro slul parameter to the correct (line) baud rate.

1.2.3.3 Nonstandard Vector and CSR on RT-11 Host - If your target
system is attached to an RT-11 host system by a serial-line interface
whose interrupt vector and CSR are not configured to 300 and 176500,
respectively, use the RT-11 commands SET TD VECTOR and SET TD CSR on
the host system to set the correct vector and CSR values.
You must
first UNLOAD and REMOVE the TD handler before typing the SET commands;
then INSTALL and LOAD the TD handler before running PASDBG.

1.2.3.4 Target System Halts on Load Command - If the PASDBG bootstrap
fails to execute properly after a LOAD command has been issued, the
target system halts, and the following error message sequence is
displayed:
?PASDBG-E-TARHALT, Target halted - PASDBG in uODT mode
?PASDBG-I-NODSM, No DSM, target not yet loaded
@

The probable cause o·f this error is that the system configuration file
used when building the kernel did not accurately describe the target
memory configuration. For example, the MEMORY macro(s) specified more
RAM than is available on the target or did not correctly specify the
base addresses of noncontiguous memory segments. You must modify the
configuration file and rebuild the application image or reconfigure
the target hardware to match the description in the configuration
file.

1.2.3.S TD Logical Device Access on RSX or VMS Host - If you invoke
PASDBG on an RSXll-M/M-PLUS or VAX/VMS host system and PASDBG cannot
access the logical device TD, the following error message
is
displayed:
?PASDBG-E-NOTD, Unable to access communication line, TD
The probable cause of this error is either that you did not assign the
logical device name TD: to the line connected to your target system
or that the line assigned as TD:
is allocated to or in use by another
user.
On a VAX/VMS host system, the error also occurs if you do not
have read/write access to the line assigned as TD:.

Version 1.5, February 1984

1-7

GETTING STARTED
1.3

BUILD PROCEDURE FOR DEBUGGING

This section outlines the build procedure you must follow in order to
debug an application program with PASDBG.
It is assumed that you have
read Chapter 3 of the MicroPower/Pascal System User's Guide for your
host system.
That chapter gives more complete information on the
application build cycle and the full range of build options.
In general, building an
following special steps:
1.

application

for

debugging

requires

the

Build a kernel with the debugger service module (DSM)
specify
debug=YES
in your
included.
To
do
that,
configuration file:
SYSTEM optimize=NO, debug=YES
or
SYSTEM optimize=YES, debug=YES

If you are using the DIGITAL-supplied command procedure
MPBUILD
(RSX or VMS)
or MPBLD
(RT-11)
to build your
application, build debugger support into your application.
You do this by answering "yes" to the debug support question
in the MPBUILD/MPBLD dialog:
Debug support required [yes] ? yes<RET>
If you use MPBUILD/MPBLD, no other special steps
are
necessary, except step 4 if your application requires the XL
handler.
Ignore steps 3 and 5 through 9 in this list.
The
MPBUILD/MPBLD command procedure is described in Appendix B of
the MicroPower/Pascal system user's guide for your host
system.

Build the kernel symbols into the application. To do that,
use the debug switch· on the kernel module while running MERGE
and RELOC and specify a DBG file for the kernel in MIB.
RT-11 Host Example
.R MACRO<RET>
*KRNM=KRNM,LB:COMM.SML/M<RET>
.RUN LB:MERGE<RET>
*KRNM.MOB/D=KRNM,LB:PAXM<RET>
*<CTRL/C>
.RUN LB:RELOC<RET>
*KRNM,KRNM,KRNM/D=KRNM.MOB<RET>
*<CTRL/C>
.RUN LB:MIB<RET>
*KRNM,KRNM.MIB,KRNM=KRNM,,KRNM/K/S<RET>
*<CTRL/C>

Version 1.5, February 1984

1-8

GETTING STARTED
RSX-llM/M-PLOS Host Example
>MAC<RET>
MAC>KRNM=MP:[2,ll]COMM.MLB/ML,dev:[uic]KRNM<RET>
>MRG<RET>
MRG>KRNM.MOB=KRNM,MP:[2,ll]PAXM/LB/DE<RET>
>REL<RET>
REL>KRNM,KRNM,KRNM/DE=KRNM.MOB<RET>
>MIB<RET>
MIB>KRNM,KRNM.MIB,KRNM=KRNM,,KRNM/KI/SM<RET>
VAX/VMS Host Example
$MCR MAC<RET>
MAC>KRNM=MICROPOWER$LIB:COMM.MLB/ML,dev:[dir]KRNM<RET>
$MPMERGE<RET>
MRG>KRNM.MOB=KRNM,MICROPOWER$LIB:PAXM/LB/DE<RET>
$MPRELOC<RET>
REL>KRNM,KRNM,KRNM/DE=KRNM.MOB<RET>
$MPMIB<RET>
MIB>KRNM,KRNM.MIB,KRNM=KRNM,,KRNM/Kl/SM<RET>
4.

If your application requires the XL handler, use the prefix
file XLPFXD.MAC instead of XLPFX.MAC to add the handler to
your application. This ensures that the application will not
use interrupt vector 60 and CSR 177560, which are reserved
for
the
host/target
serial
line.
(For
SBC-11/21
applications, use the prefix file XLPFXF.MAC; for KXTll-C
applications, use XLPFXK.MAC.)
RT-11 Host Example
.R MACRO<RET>
*XLPFXD=XLPFXD.MAC,LB:COMM.SML/M<RET>
RSX-llM/M-PLUS Host Example
>MAC<RET>
MAC>XLPFXD•MP:[2,ll]COMM.MLB/ML,dev:[uic]XLPFXD.MAC<RET>
VAX/VMS Host Example
$MCR MAC<RET>
MAC>XLPFXD=MICROPOWER$LIB:COMM/ML,dev:(dir]XLPFXD<RET>
If you are using the MPBUILD/MPBLD command procedure to build
an application that requires the XL handler, specify the
XLPFXD prefix file (XLPFXF for SBC-11/21, XLPFXK for KXTll-C)
in
response
to
the
handler prefix question in the
MPBUILD/MPBLD dialog:
Handler prefix file spec ? XLPFXD.MAC<RET>
Is this a Pascal-Implemented handler [no]

version 1.5, February 1984

1-9

? <RET>

GETTING STARTED
5.

Generate the symbols for the Pascal modules you wish to
debug. To do so, use the debug switch switch in the compiler
command line.
RT-11 Host Example
.R PASCAL<RET>
*ACE=ACE/D<RET>
RSX-llM/M-PLUS Host Example
>MPP<RET>
MPP>ACE=ACE/DE<RET>
VAX/VMS Host Example
$MPPASCAL<RET>
MPP>ACE=ACE/DE<RET>
For a MACR0-11 static process or routine that you wish to
debug, you generate the ISD records for the module's global
symbols not at assembly time but at merge time, via the MERGE
debug option (see step 6). Do not use the assembler debug
option (E:DBG), as it generates debug information in a format
incompatible with PASDBG.
RT-11 Host Example
.R MACRO<RET>
*ACE=ACE,LB:COMM.SML/M<RET>
RSX-llM/M-PLUS Host Example
>MAC<RET>
MAC>ACE=MP:[2,19]COMM.MLB/ML,dev:[uic]ACE<RET>
VAX/VMS Host Example
$MCR MAC<RET>
MAC>ACE=MICROPOWER$LIB:COMM.MLB/ML,dev:[dir]ACE<RET>

Include the debug symbols for the modules you wish to debug
in the MOB file.
To do that, use the debug switch in the
MERGE command line.
If you are merging a MACR0-11 static
process, you can omit the Pascal object-time library (LIBxxx)
from the command line.
RT-11 Host Example
.RUN LB:MERGE<RET>
*ACE=ACE/D,KRNM.STB,LB:LIBNHD<RET>
*<CTRL/C>
RSX-llM/M-PLUS Host Example
>MRG<RET>
MRG>ACE=ACE/DE,KRNM.STB,MP:[2,ll]LIBNHD/LB<RET>
VAX/VMS Host Example
$MPMERGE<RET>
MRG>ACE=ACE/DE,KRNM.STB,MICROPOWER$LIB:LIBNHD/LB<RET>

Version 1.5, February 1984

1-10

GETTING STARTED
7.

Relocate the debug symbols along with the code.
use the debug switch in the RELOC command line.

To do

that,

RT-11 Host Example
.RUN LB:RELOC<RET>
*ACE,ACE,ACE=ACE/D<RET>
*<CTRL/C>
RSX-llM/M-PLUS Host Example
>REL<RET>
REL>ACE,ACE,ACE=ACE/DE<RET>
VAX/VMS Host Example
$MPRELOC<RET>
REL>ACE,ACE,ACE=ACE/DE<RET>
If you are relocating a MACR0-11 static process and if you
did not name your program at source level via a .TITLE
statement, you must explicitly name the program.
(Use the
name switch.)
The name you specify must match the static
process name you specified at source level in the DFSPC$
(Define Static Process) macro call for the process.
RT-11 Host Example
.RUN LB:RELOC<RET>
*ACE,ACE,ACE=ACE/D/N<RET>
Program Name? ACE<RET>
*<CTRL/C>
RSX-llM/M-PLUS Host Example
>REL<RET>
REL>ACE,ACE,ACE=ACE/DE/NM:ACE<RET>
VAX/VMS Host Example
$MPRELOC<RET>
REL>ACE,ACE,ACE=ACE/DE/NM:ACE<RET>
NOTE
use the name switch only if you did not
name your program at source level. To
name your program at source level, you
must include a .TITLE statement at the
beginning of the
first
application
module that is to be linked by MERGE.
The name you specify in your initial
.TITLE statement must match the static
process name you specified in the DFSPC$
macro call for the process.
8.

Copy or rename the kernel DBG file generated in step 3 into a
file with the same name as the final MIM file you wish to
produce but with the DBG extension.
For the example build in this section,
would be copied or renamed to ACE.DBG.

Version 1.5, February 1984

1-11

the

file

KRNM.DBG

GETTING STARTED
9.

Produce a DBG file with your MIM file.
DBG file in the MIB command line.

To do that, specify a

RT-11 Host Example
.RUN LB:MIB<RET>
*ACE,ACE.MIB,ACE.DBG=ACE,KRNM,ACE/S<RET>
*<CTRL/C>
RSX-llM/M-PLUS Host Example
>MIB<RET>
MIB>ACE,ACE.MIB,ACE.DBG=ACE,KRNM,ACE/SM<RET>
VAX/VMS Host Example
$MPMIB<RET>
MIB>ACE,ACE.MIB,ACE.DBG=ACE,KRNM,ACE/SM<RET>

1.4

BEGINNING A DEBUGGI~G SESSION

This section explains how to invoke the PASDBG symbolic debugger and
how to issue debugger commands.
The section ends with a list of
debugger commands.
On an RT-11 host system that has hard-disk storage, PASDBG resides by
default on the RT-11 logical disk LB:. You invoke PASDBG with the
command:
.RUN LB:PASDBG<RET>
On a floppy-diskette-only RT-11 host system, PASDBG resides
You invoke PASDBG with either of the following commands:

SY:.

.RUN SY:PASDBG<RET>
.R PASDBG<RET>
On an RSX-llM/M-PLUS host system, PASDBG resides by default in logical
device/directory MP: [2,10]. You invoke PASDBG with the command:
>PDB<RET>
On a VAX/VMS host system, PASDBG resides by default in logical
device/directory MICROPOWER$LIB:. You invoke PASDBG with the command:
$PASDBG<RET>
NOTE
On an RSX-llM/M-PLUS or VAX/VMS host
system, you must assign the host/target
communication line and correctly set its
characteristics before invoking PASDBG.
See
Chapter
10
of
the
MicroPower/Pascal-RSX/VMS sistem User's
Guide for instructions on doing so.
On
a--vAX/VMS host system, you must also
execute the MPSETUP command file, as
directed
in
Chapter
1
of
the
MicroPower/Pascal-RSX/VMS System User's
Guide.
Version 1.5, February 1984

1-12

GETTING STARTED
PASDBG responds with a debugger version number, a message
the state of the target system, and the following prompt:

reporting

PASDBG>
The prompt signifies that PASDBG is waiting for a user
format for debugger commands is as follows:

command.

The

PASDBG>command [!comment]<RET>
In the command .line above, "PASDBG>" is the debugger command-mode
prompt, "command" is a debugger command, and "comment" is an optional
comment that is echoed but ignored by PASDBG.
The first command issued in a debugging session is usually a LOAD
command, a LOG command, a HELP command, or an @ command.
LOAD
down-line loads the application program and/or loads application
symbols, LOG opens a log file,
HELP requests information about
debugger commands, and @ invokes an indirect command file.
To end a debugging session, issue the EXIT command as follows:
PASDBG>exit<RET>
Table 1-1 lists the debugger commands with their associated keywords.
Table 1-1
Debugger Commands
Command

Description

Invoke indirect command file

CANCEL BREAK
/ALL

Cancel breakpoint(s)

CANCEL PROCESS

Cancel process and mapping

CANCEL SCOPE

Cancel lexical scope

CANCEL STEP

Cancel SET STEP parameters

CANCEL TRACE
/ALL

Cancel tracepoint(s)

CANCEL WATCH
/ALL

Cancel watchpoint(s)

Close log file

CTRL/C

Exit

CTRL/O

Suppress terminal output

CTRL/Y

Exit (VAX/VMS host only)
(Continued on next page)

Version 1.5, February 1984

1-13

GETTING STARTED

Table 1-1
(Cont)
Debugger Commands
Command

Description

DEPOSIT
/BYTE

Deposit data

EXAMINE
/ASCII
/BINARY
/BYTE
/DECIMAL
/HEXADECIMAL
/INSTRUCTION
/OCTAL
/RAD50
/REAL
/WORD

Examine memory location(s)

EXIT

Exit debugger

Start/continue execution
/EXIT

HALT

Stop target

HELP

Display help text

INIT
/RESTART

Initialize application

LOAD
/EXIT
/SYMBOL
/TARGET

Load application and/or symbols

LOG

Open log file

SET BREAK
/AFTER
/PROCESS

Set breakpoint

SET ODT

Enter target ODT

SET PHYSICAL

Set physical addressing

SET PROCESS

Set process mapping

SET PROGRAM

Set upper-level scope

SET SCOPE

Set lower-level scope

SET STEP
INSTRUCTION
INTO
OVER
STATEMENT

Set step parameters

(Continued on next page)

Version 1.5, February 1984

1-14

GETTING STARTED

Table 1-1
(Cont)
Debugger Commands
Description

Command
SET TRACE
/AF.TER
/PROCESS

Set tracepoint

SET WATCH
/AFTER

Set watchpo int

SHOW BREAK

List breakpoints

SHOW CALLS

Display procedure call chain

SHOW EXCEPTION

Display last exception

SHOW EXCEPTION GROUPS

Display exception handling

SHOW FREE PACKETS

Display available packets

SHOW FREE STRUCTURES

Display available kernel pool

SHOW INACTIVE QUEUE

List aborted processes

SHOW NAMES

List named kernel structures

SHOW PACKET QUEUE

Display packet queue

SHOW PCB

Display process information

SHOW PROCESS
/ALL

Display mapping or list process(es)

SHOW READY/ACTIVE QUEUE

List ready-active processes

SHOW READY/SUSPENDED QUEUE

List ready-suspended processes

SHOW RING BUFFER

Display ring buffer

SHOW RUN QUEUE

Display running process

SHOW SCOPE

Display current lexical scope

SHOW SEMAPHORE

Display binary/counting semaphore

SHOW STEP

List step parameters

SHOW STRUCTURE

Display program/process/routine/variable
structure

SHOW TARGET

Display state of application

SHOW TRACE

List tracepoints

SHOW WATCH

List watchpoints
(Continued on next page)

Version 1.5, February 1984

1-15

GETTING STARTED
Table 1-1
(Cont)
Debugger Commands
Command

Description

SPAWN

Execute host command without exiting
(RSX-llM/M-PLUS or VAX/VMS host only)

STEP
/INSTRUCTION
/INTO
/OVER
/STATEMENT

Execute incrementally

1.5

SAMPLE DEBUGGING SESSION

This section presents a sample debugging session.
The session does
not locate errors in the sample program used but illustrates some of
the basic debugger functions.
The commands used in this debugging
session
including the invocation of the debugger -- are shown in
boldface type.
See Section 1.4 and Chapter 3 for alphabetical lists
of the debugger commands.
The application used for this debugging session
fol lowing files:

was

built

from

File

Description

PROCS2.PAS

Pascal source file

CFDUNM.MAC

Configuration file for debugging

COMO. SML/ .MLB

System macro library file (unmapped)

PAXU.OBJ/.OLB

Kernel module library file (unmapped)

XLPFXD.MAC

XL driver prefix file for debugging

DRVU. OB.J/ .OLB

Driver library file (unmapped)

L IBNHD. OBJ/. OLB

OTS module library file (unmapped)

Version 1. 5, February 1984

1-16

the

GETTING STARTED
The MicroPower/Pascal compiler generated the following listing of
user-process source code in PROCS2.PAS:
Line

Stmt

Source
[ SYSTEM (MICROPOWER) ] PROGRAM procs2;
VAR j,k : INTEGER;

1
2
3

4
5
6
7
8
9

10
11

12
13
14
15
16
17
18
19
20
21
22

the

PROCESS pl;
VAR i
INTEGER;
BEGIN
1
FOR i .- 0 TO 100 DO
BEGIN
2
WRITELN ('in pl, i=' ,i:3);
END
3 END;
LABEL 10;
BEGIN
1
pl;
2
k .- 2;
3
~ . - 100;
4 10: J .- j-1;
5
WRITELN ('in main block, j=' ,j: 3);

6
7

IF j>0 THEN GOTO 10;
WRITELN('Process test finished');

8 END.

The Pascal statement numbers listed in the "Stmt" column above can be
used in debugger commands to reference locations within the program.
Note that the statement numbers repeat for each process, procedure, or
function.
While
debugging,
you distinguish between identical
statement numbers by issuing the SET SCOPE command.
(See Chapter 3.)
The debugging session begins with the invocation of PASDBG below. For
an RSX-llM/M-PLUS or VAX/VMS host,
it is assumed that you have
correctly set up the host/target communication line and assigned it
the
logical
name
TD:,
as
directed
in Chapter 10 of the
MicroPower/Pascal-RSX/VMS System User's Guide.
.RUN LB:PASDBG<RET>
or
>PDB<RET>
or
PASDBG vxx.xx
<-- Version number displayed here
;PASDBG-I-NODSM, No DSM, target not yet loaded
PASDBG>log dialog.log<RET>

$PASDBG<RET>

!Log debugging session

PASDBG>load/target procs2<RET>
!Down-line load application program
;PASDBG-I-BOTWARN, Starting primary boot load, please wait ...
;PASDBG-I-BOTLD, Primary boot loaded, getting closer •••
Target stopped at physical (00007716), virtual
Executing KERNEL code
No process set, KERNEL mapping in effect
PASDBG>show target<RET>

(007716)

!Display state of application

Target stopped at physical (00007716), virtual (007716)
Executing KERNEL code
No process active
Not using memory management hardware

Version 1.5, February 1984

: JMP @#10676

1-17

JMP @#10676

GETTING STARTED
PASDBG>show scope<RET>
Program KERNEL
;PASDBG-I-KSYNAC, Mapping set, KERNEL symbols not available
PASDBG>show process<RET>
No process set, KERNEL mapping in effect
PASDBG>load/symbol procs2<RET>

!Get Pascal and KERNEL symbols

Target stopped at physical (00007716), virtual
Executing KERNEL code
No process set, KERNEL mapping in effect

{~07716)

: JMP @#10676

PASDBG>show scope<RET>
Program KERNEL
PASDBG>set program procs2<RET>
!Set lexical scope to program
;PASDBG-I-NOMOD, Module and Scope set to "PROCS2"
PASDBG>show scope<RET>
Program PROCS2, Module PROCS2, Scope: PROCS2
PASDBG>show process<RET>
!Display currently set process
Process 6, name = 'PROCS2', PCB at KERNEL (035436)
PASDBG>show step<RET>
Step parameters: into statement
PASDBG>set step over statement<RET>
PASDBG>set break l<RET>

!Set break on stmt 1 in PROCS2

PASDBG>set watch~k<RET>

!Set watch on PROCS2 variable

PASDBG>set trace label 19<RET>
PASDBG>set scope pl<RET>

!Set trace on PROCS2 label

!Set lexical scope to process Pl

PASDBG>set break 1 'top of pl'<RET>
PASDBG>show break<RET>
# Physaddr AFTER count
0 00053012
1
0
2 00052720
1
0

process S.N.
{any)
{any)

TAG
'l PROCS2'
'top of pl'

PASDBG>show trace<RET>
# Physaddr AFTER count
l
00053104
1
0

process S.N.
{any)

TAG
'LABEL 10 PROCS2'

PASDBG>show watch<RET>
# Physaddr AFTER count
0 00053304
1
0

process S.N.
{any)

TAG
'K'

PASDBG>go<RET>
!Start program execution
[Target execution resumed - type <CR> to stop target]
** BREAKPOINT #0 'l PROCS2'
Target stopped at physical {00053012), virtual {053012)
@#53300,- {SP)
In statement 1 + 0 in
Program PROCS2, Module PROCS2, Scope: PROCS2
Process 6, narr.e = 'PROCS2', PCB at KERNEL (035436)

Version 1.5, February 1984

1-18

MOV

GETTING STARTED
PASDBG>go<RET>
!Continue program execution
[Target execution resumed - type <CR> to stop target]
** WATCHPOINT #0 'K'
Old contents: 0
New contents: 2
Target stopped at physical (00053012) , virtual (053012)
@#53300, - (SP)
In statement 3 + 0 in
Program PROCS2, Module PROCS2, Scope: PROCS2
Process 6, name= 'PROCS2', PCB at KERNEL (035436)

MOV

PASDBG>cancel watch k<RET>
PASDBG>go<RET>
!Stop target with <RET>
[Target execution resumed - type <CR> to stop target]
<RET>
Target stopped at physical (00053076) , virtual (053076)
#144,@#53302
Executing non-Pascal code
No process set, KERNEL mapping in effect

MOV

PASDBG>examine k<RET>
!Show that scope was reset by PASDBG
?PASDBG-E-SYMNDF, Symbol not defined in current scope
PASDBG>show scope<RET>
!In non-Pascal code, no scope
?PASDBG-E-NOSCOPE, No scope set
PASDBG>set program procs2<RET>
!Reset scope
PASDBG-I-NOMOD, Module and Scope set to "PROCS2"
PASDBG>examine k<RET>
053304 : 2

!Display contents of variable K

PASDBG>examine j<RET>
053302 : 100

!Display loop-control variable

PASDBG>go<RET>
!Interrupt with <RET> again
[Target execution resumed - type <CR> to stop target]
** TRACEPOINT #1 'LABEL 10 PROCS2'
** TRACEPOINT #1 'LABEL 10 PROCS2'
** TRACEPOINT #1 'LABEL 10 PROCS2'
** TRACEPOINT #1 'LABEL 10 PROCS2'
<RET>
Target stopped at physical (00010440) , virtual (010440)
SP,@#32022
Executing non-Pascal code
Process 6, name= 'PROCS2', PCB at KERNEL (035436)

MOV

PASDBG>show scope<RET>
!Show scope was updated (cancelled)
?PASDBG-E-NOSCOPE, No scope set
PASDBG>s<RET>

!Step to next statement (reset scope)

Target stopped at physical (00053146), virtual (053146)
In statement 7 + 0 in
Program PROCS2, Module PROCS2, Scope: PROCS2
Process 6, name= 'PROCS2', PCB at KERNEL (035436)
PASDBG>show scope<RET>
Program PROCS2, Module PROCS2, Scope: PROCS2
PASDBG>examine j<RET>
0533@2 : 96

!Examine loop-control variable

Version 1.5, February 1984

1-19

TST @#53302

GETTING STARTED
PASDBG>examine 6<RET>
!Display instruction at stmt 6
053110 : MOV #53224,-(SP)
PASDBG>examine 5 •• 7<RET>
!Disassemble stmts 5 •• 6 in PROCS2
053104
DEC
@#53302
053110
MOV
t53224, - (SP)
0 53114
MOV
*21,-(SP)
053120
MOV
(SP) ,-(SP)
053122
JSR
PC,45074
053126
MOV
@#53302, - (SP)
053132
MOV
*3,-(SP)
0 53136
JSR
PC, 45252
053142
JSR
PC,45042
053146
TST
@#53302
PASDBG>ex %r4<RET>
R4 :
0

!Display register 4 contents

PASDBG>show break<RET>
!List currently set breakpoints
# Physaddr AFTER count
process S.N.
TAG
0 00053012
1
0
(any)
'l PROCS2'
0
(any)
'top of pl'
2 00052720
1
PASDBG>cancel break f 0<RET>
PASDBG>set break 6<RET>

!Cancel breakpoint number 0

!Set break at stmt 6 in PROCS2

PASDBG>go<RET>
[Target execution resumed - type <CR> to stop target]
** TRACEPOINT #1 'LABEL 10 PROCS2'
** BREAKPOINT #0 '6 PROCS2'
Target stopped at physical (00053110), virtual (053110)
#53224,-(SP)
In statement 6 + 0 in
Program PROCS2, Module PROCS2, Scope: PROCS2
Process 6, name = 'PROCS2', PCB at KERNEL (035436)
PASDBG>cancel break f 0<RET>

MOV

!Cancel the break just triggered

PASDBG>examine j<RET>
053302 : 94

!Recheck loop control variable

PASDBG>deposit j=l<RET>

!Force loop to terminate

PASDBG>g<RET>
!Should trigger Pl breakpoint
[Target execution resumed - type <CR> to stop target]
** BREAKPOINT #2 'top of pl'
Target stopped at physical (00052720), virtual (052720)
In statement 1 + 0 in
Program PROCS2, Module PROCS2, Scope: Pl
Process 9, {no name), PCB at KERNEL (035116)
PASDBG>show scope<RET>
!Lexical scope has been reset
Program PROCS2, Module PROCS2, Scope: Pl
PASDBG>show process<RET>
!Mapping has been reset
Process 9, (no name), PCB at KERNEL (035116)

Version 1.5, February 1984

1-20

CLR R4

GETTING STARTED
PASDBG>show structure pl<RET>
PROCESS Pl
NAME: ARRAY [1 •• 6] OF
: CHAR
PRIORITY : INTEGER
STACK SIZE : INTEGER
DESC T INTEGER
I : INTEGER

!Display structure of Pl

PASDBG>show break<RET>
!List breakpoints
# Physaddr AFTER count
process S.N.
2 00052720
1
0
(any)
PASDBG>init<RET>

TAG
'top of pl'

!Reinitialize STEP, BREAK, WATCH, etc.

Target stopped at physical (00052720), virtual
In statement 1 + 0 in
Program PROCS2, Module PROCS2, Scope: Pl
Process 9, (no name), PCB at KERNEL (035116)

(~52720)

: CLR R4

PASDBG>show step<RET>
!See that default parameters were reset
Step parameters: into statement
PASDBG>init/rest<RET>

!Reinit application to starting point

Target stopped at physical (~0007716), virtual
Executing KERNEL code
No process set, KERNEL mapping in effect
PASDBG>exit<RET>

(~07716)

!Close log file and exit to monitor

Version 1.5, February 1984

1-21

: JMP @#10676

CHAPTER 2
DEBUGGING TECHNIQUES

This chapter surveys the general-purpose debugging features PASDBG
provides
(Section 2.1), describes the PASDBG features that allow you
to debug real-time programs
(Section 2.2), and presents practical
hints and suggestions to keep in mind when debugging MicroPower/Pascal
programs (Section 2.3).
PASDBG has five types of commands:
1.

Commands that load
symbolic debugging

your

application

Commands that establish a context
lexical scope and
mapping -- for symbol and address references in the debugger
commands you issue

Commands that control the execution of your program

Commands that allow you to examine and
and data

Commands that allow you to examine
structures in your program

the

and

its

symbols

for

modify

your

program

states

and

control

The first four types of commands are discussed in Section 2.1.
The
fifth type is discussed in Section 2.2.
Refer to Chapter 3 for
information on command format, parameters, and qualifiers and for
examples of command use.

2.1

GENERAL DEBUGGING

This section describes PASDBG's general-purpose debugging commands.
These commands load your application and its symbols, establish a
context for references to symbols and addresses, control program
execution, and examine or modify your program.

2.1.1

Loading the Application Program

The LOAD command down-line loads a copy of the application program
into
the
target
computer
and/or
establishes access to the
application's symbol table for symbolic debugging.
The LOAD command
qualifiers /TARGET, /SYMBOL, and /EXIT select the specific type of
load operation to be performed.

2-1

DEBUGGING TECHNIQUES
LOAD/TARGET
Down-line loads a copy of the application program into the target
system.
LOAD/SYMBOL
Loads a copy of the application program's symbol table into
PASDBG.
PASDBG uses this symbol table to access symbols in the
user's program -- including statement numbers, label numbers, and
names of programs, modules, processes, procedures, functions, and
variables -- and to access kernel symbols. Without this table,
PASDBG
cannot
resolve symbol references, and symbol- and
kernel-specific commands, such as EXAMINE FOO and SHOW RUN QUEUE,
do not work.
LOAD

Performs a LOAD/TARGET, a LOAD/SYMBOL, or both, depending on the
file extension you give in the command line -- .MIM, .DBG, or
none specified, respectively.

LOAD/EXIT
Down-line loads a copy of the application program into the target
system, starts the application, and then exits to the host
operating system, leaving the target running.

2.1.2

Controlling Symbol and Address Resolution

The following commands are used to establish a context
lexical
scope and mapping -- for symbol and address references in the debugger
commands you issue.
SET PROGRAM
SET PHYSICAL
SET SCOPE
SHOW SCOPE
CANCEL SCOPE
SET PROCESS
SHOW PROCESS
CANCEL PROCESS

2.1.2.1 PROGRAM, SCOPE, and SET PHYSICAL - The PROGRAM and SCOPE
commands establish a lexical context that allows you to reference a
symbol in your application program without ambiguity.
With SET
PROGRAM and SET SCOPE, you can tell the debugger exactly which set of
symbols to use when interpreting symbol references in future debugger
commands.
This makes it possible for the debugger to distinguish
between multiple occurrences of a symbol name in your application.
You must issue at least a SET PROGRAM command if you want to access
Pascal or kernel symbols in your application.
SET PROGRAM
Sets lexical scope to a Pascal or a MACR0-11 program in your
application.
PASDBG will use the specified program's symbols to
resolve future symbolic references in debugger commands.
You
must issue a SET PROGRAM in order to reference Pascal or MACR0-11
symbols with PASDBG; otherwise, you can access only physical
locations within your application.

Version 1.5, February 1984

2-2

DEBUGGING TECHNIQUES
The \MODULE option on a SET PROGRAM lets you set lexical scope to
a
particular Pascal module within a particular program.
(A
Pascal module can appear more than once in an application.)
The
default for \MODULE
is the program -- the module that contains
the program declaration.
SET PROGRAM KERNEL sets lexical scope to the kernel.
you to reference kernel symbols.

This allows

SET PROGRAM performs an implicit SET PROCESS to the program's
main
(static) process or, if KERNEL is specified, to the kernel.
In a virtual system,
this establishes process, or kernel,
mapping.
(See the PROCESS commands, below.)
SET PROGRAM resets the scope set with SET SCOPE to the specified
\MODULE.
If no module is specified, scope is reset to the main
block of the program.
If PROGRAM is not set, PASDBG can access and modify physical
locations in memory -- up to 64K bytes for unmapped systems and
up to 4M bytes for mapped systems.
If PROGRAM is set, PASDBG can
access variables within the specified program's memory space
symbolically or by virtual address.

SET PHYSICAL
Cancels program, scope, and process settings and sets PASDBG
physical addressing mode.
Symbolic access is disabled.

NOTE
The program setting can change whenever
the
application
stops.
If
the
application stops in non-Pascal code
in the kernel,
the OTS, or a MACR0-11
program -- PASDBG cancels the program
setting.
If the application stops in a
different program,
PASDBG resets the
scope to the currently running program,
procedure,
function,
or
process.
Because the program setting is subject
to change, PASDBG displays the current
program,
process,
and scope settings
whenever execution is interrupted.
SET SCOPE
Establishes a context for symbolic references at the procedure,
function,
or process level.
SET SCOPE sets lexical scope to a
procedure,
function,
or process within the
currently
set
program\module (see SET PROGRAM).
PASDBG will use the symbols of
the specified procedure,
function,
or process
or,
if
necessary, will search upward through the lexical path that leads
to the procedure, function,
or process
to resolve future
symbolic references in debugger commands. Setting lexical scope
properly with SET PROGRAM and SET SCOPE allows you to reference
the symbols in your application without ambiguity.
Lexical scope must be set at the program or module level before
you set scope to a procedure, function, or process.
Use SHOW
SCOPE to see if program is currently set. When you set program,
scope defaults to the main block of the program or module. When
you cancel program (with SET PHYSICAL), scope is also canceled.

2-3

DEBUGGING TECHNIQUES
NOTE
Whenever the debugger stops the target
system,
scope is reset to the currently
running program, procedure, function, or
process,
if any.
If the application
stops in
non-Pascal
code
the
MicroPower/Pascal
kernel, OTS, or a
MACR0-11 program
PASDBG
cancels
scope.
SHOW SCOPE
Displays the current lexical context for symbol
including program, module, and scope settings.

references,

CANCEL SCOPE
Clears the current scope setting;
program and module settings
remain in effect. No scoped Pascal data or code references are
allowed until a new scope is set.
The following example illustrates the relationship between the PROGRAM
and SCOPE commands and shows the concept of lexical positions.
[SYSTEM(MICROPOWER)] PROGRAM OUTER;
VAR I : INTEGER;
PROCEDURE INNER;
VAR I : BOOLEAN;
BEGIN {INNER}
I := TRUE;
END;
BEGIN {OUTER}
INNER;
I

:= 3;

END.
The example uses an integer variable called "I" and a Boolean variable
called "I". To examine either variable, you must set lexical scope to
the block of code where the variable is found as a local variable.
For example,
to examine the integer variable I, use the SET PROGRAM
command to set scope to program OUTER.
You can now examine the
integer variable I, because the SET PROGRAM command automatically sets
scope to the main block of the program -- in this case, OUTER --:and
integer variable I is local to this block. Refer to the sample dialog
below for an illustration.
To examine the Boolean variable I, you must use a more specific scope.
With program set to OUTER, use the SET SCOPE command to specify the
lexical path to the location where Boolean variable I . is
local
variable.
In this case, scope is INNER because Boolean variable I is
a local variable of the INNER procedure of program OUTER.
Refer to
the sample dialog below.

PASDBG>SET PROGRAM OUTER<RET>
PASDBG>EXAMINE I<RET>
013245: 3
PASDBG>SET SCOPE INNER<RET>
PASDBG>EXAMINE I<RET>
TRUE

0 12 4 2 5 :

2-4

DEBUGGING TECHNIQUES
2.1.2.2 PROCESS - Every process has a stack -- an area in memory for
maintaining the values of variables local to that process and the
values of variables local to Pascal routines called by the process.
Because one process can repeatedly initiate a second process that is
capable of running independently of the first, thereby creating other
stacks with the same variables but different values, PASDBG requires
that you establish a process context -- "set process" -- before you
access a process's local variables. With the PROCESS commands, you
tell PASDBG exactly which process's variables you wish to access.
(See also the SET PROGRAM command.)
Wherever the application system stops, PASDBG resets process to the
currently running process,
if any, and displays the new process
setting.
SET PROCESS
Establishes a process context and,
in a virtual system,
sets
mapping
to the specified process. SET PROCESS makes it possible
to access a process's stack and local variables.
SHOW PROCESS
Displays the currently set process, a process you specify, or all
processes.
CANCEL PROCESS
Cancels the process set with SET PROCESS, cancels the lexical
scope set with SET SCOPE, and performs a SET PROCESS to the
program set with SET PROGRAM.
If no SET PROGRAM was issued,
physical addressing
is set.
After process has been canceled,
variables local to the canceled process can be accessed only by
physical address.

2.1.3

Controlling Program Execution

The following commands allow you to
application program.
GO
SET STEP
SHOW STEP
STEP
CANCEL STEP
SET BREAK
SHOW BREAK
CANCEL BREAK
SET TRACE
SHOW TRACE
CANCEL TRACE
SET WATCH
SHOW WATCH
CANCEL WATCH
SHOW CALLS
!NIT

2-5

control

the

execution

your

DEBUGGING TECHNIQUES
2.1.3.1 Starting and Stopping Execution - The GO and STEP
are used to regulate manually the execution of your program.

co~mands

When you issue the GO command, PASDBG instructs the application to
restart from the point at which it was stopped.
If the application
has not yet run, the application starts at its starting address in the
kernel.
You must issue a GO command to start the application program
initially when using the debugger. To restart an application from its
starting address, use the !NIT/RESTART command.
When you issue a GO command, PASDBG displays the following message:
[Target execution resumed - type <CR> to stop target]
To interrupt program execution, type a carriage return.
PASDBG will
respond
by
resetting scope to the currently running program,
procedure, function, or process,
reporting on the state of the
application, and returning to PASDBG> prompt level.
The /EXIT qualifier to the GO command instructs PASDBG to start or
continue program execution and then exit to the host monitor, leaving
the application running.
The STEP command permits you to go through the execution of the
application program step by step. You can step between Pascal program
statements or PDP-11 instructions. You can also step into or skip
over all subroutine calls, including calls to the MicroPower/Pascal
object time system (OTS).
GO
Starts the application at its starting point in the kernel or
restarts the application from the point at which it was stopped.
After issuing a GO,
type a carriage return to stop
the
application program.
The /EXIT qualifier causes PASDBG to exit
to the host monitor after (re)starting the application.
SET STEP
Sets the parameters for
the STEP command.
INTO directs the
debugger to step into subroutine calls, OVER to skip over
subroutine calls, INSTRUCTION to step by PDP-11 instruction
increments, and STATEMENT to step by Pascal statement increments.
SHOW STEP
Lists the current step parameters.
STEP
in
instruction
or
Single-steps through program execution
statement increments.
The /INSTRUCTION, /STATEMENT, /INTO, and
/OVER qualifiers can be used to override the current step
parameter settings.
CANCEL STEP
Cancels the step parameters set with SET STEP and
parameters to the system default -- STATEMENT, INTO.

2-6

resets

the

DEBUGGING TECHNIQUES
2.1.3.2 BREAK, TRACE, and WATCH - The BREAK, TRACE,
and
WATCH
commands permit you to set breakpoints, tracepoints, and watchpoints
in your application program.
Breakpoints notify you and stop the application
specified instruction is about to execute.

program

whenever

Tracepoints notify you but do not stop the application
whenever a specified instruction is about to execute.
Watchpoints notify you and stop the
specified location is modified.

application

program

whenever

When your program stops because it triggered a breakpoint or a
watchpoint,
the debugger prompts you for command input. You can
continue program execution with a GO or a STEP command, or you can
enter other commands before continuing execution. The breakpoint,
tracepoint, or watchpoint remains set after it is triggered
until
you cancel it with a CANCEL command.
You can defer a breakpoint, tracepoint, or watchpoint by using
the
/AFTER
switch
to specify that the breakpoint, tracepoint, or
watchpoint must be triggered a particular number of times before the
debugger notifies you.
SET BREAK
Sets a breakpoint in the application program at the location you
specify.
A breakpoint stops the processor every time the
instruction at the specified program location is about to
execute.
SHOW BREAK
Lists all currently set breakpoints.
CANCEL BREAK
Removes one or all breakpoints.
SET TRACE
Sets a tracepoint in the application at the location you specify.
A tracepoint notifies you every time the instruction at the
specified program location is about to execute,
then continues
execution.
SHOW TRACE
Lists all currently set tracepoints.
CANCEL TRACE
Removes one or all tracepoints.
SET WATCH
Sets a watchpoint on the variable or location you specify.
A
watchpoint stops the processor every time the specified location
is modified.
SHOW WATCH
Lists all currently set watchpoints.
CANCEL WATCH
Removes one or all watchpoints.

2-7

DEBUGGING TECHNIQUES
2.1.3.3 Invocation Chain Display - The SHOW CALLS command locates the
chain of called routines -- procedures, functions, and processes -~ in
the currently running process. Many different procedures, functions,
or processes can call a particular routine. SHOW CALLS retroactively
traces and lists the chain of calls that resulted in execution of the
currently running routine. Do not confuse the chain of calls listed
by SHOW CALLS with lexical scope. You display the lexical scope of a
procedure, function, or process with the SHOW SCOPE command.
SHOW CALLS
Lists the chain of procedures, functions,
invoked the currently running routine.

processes

that

2.1.3.4 Reinitializing
and
Restarting - The
!NIT
command
reinitializes the debugger's internal database, canceling breakpoints,
tracepoints, and watchpoints and resetting scope and step parameters.
PASDBG performs an implicit INIT at start-up time and when it executes
a LOAD command.
The !NIT/RESTART command performs an INIT and then
application to its starting address in the kernel.
a LOAD command if you suspect that the application
been corrupted.

reinitializes the
You should reissue
program code has

INIT
Cancels breakpoints, tracepoints, watchpoints;
resets scope,
program\module,
and process;
and resets the default step
parameters.
The /RESTART command option reinitializes
the
application to its starting point.

2.1.4

Examining and Modifying Data

The following commands are used to examine and modify your application
program and data.
EXAMINE
DEPOSIT
SHOW STRUCTURE

2.1.4.l Variable Modification and Display - The EXAMINE and DEPOSIT
commands let you observe or modify specified locations, registers, or
Pascal variables in your application. You can also examine, but not
modify, specified Pascal statements.
Use EXAMINE to determine the current values of data and code
program.

your

For data, use the EXAMINE command to display the contents of a PDP-11
location or register or -- if program, scope, and process are set -the contents of a Pascal variable. PASDBG displays a Pascal variable
according
to
its
data
type
as
specified
in
the
user
program -- real-number variables are displayed as reals, characters
are displayed as characters, and so forth.

2-8

DEBUGGING TECHNIQUES
For code, use the EXAMINE command to display instructions in PDP-11
format or to "disassemble" Pascal statements into the equivalent
PDP-11 instructions.
Use DEPOSIT to change the contents of a memory location,
or a Pascal variable.

EXAMINE
Displays the contents of a location, a register, a statement, or
a variable -- or a range of locations, registers, or statements.
DEPOSIT
Replaces the contents of a memory
Pascal variable.

location,

2.1.4.2 Structure Display - The SHOW STRUCTURE command has
two
functions.
If you specify a variable or a field name, SHOW STRUCTURE
lists the type of that variable or field and the names and types of
any subfields in the variable or field.
If you specify a Pascal
routine name -- a procedure, process, program, or function name
SHOW STRUCTURE lists the type of that routine, the names and types of
any lexically subordinate routines, and the types of all local
variables.
SHOW STRUCTURE
Displays the structure of a Pascal variable, function, procedure,
process, or program.

2.1.5

General Debugging Aids

This section lists general-purpose debugger commands that do not fit
into any of the categories covered in Sections 2.1.1 through 2.1.4.
See also Section 2.2.4.
@

Invokes an indirect command file.
PASDBG displays the commands
from the file and the debugger response, if any, one command at a
time.
LOG
Copies the debugging session dialog or, alternatively, only the
commands you issued to PASDBG into a log file on the host system.
You can use LOG to generate indirect command files.
CLOSE
Closes an open log file.
EXIT
Terminates execution of PASDBG and returns control to the host
operating system.
The application program does not halt but is
left stopped.
(To exit and leave the application running, use
the GO/EXIT command.)
HALT
Forces the application program to stop.
This command is not
usually necessary, since <RET> after a GO command will stop the
application program.

2-9

DEBUGGING TECHNIQUES
CTRL/C
If the application is executing, stops the application system and
returns to PASDBG> prompt level.
If a PASDBG command or a
command procedure is executing, CTRL/C aborts the command or
command procedure and returns to PASDBG> prompt level.
If PASDBG
has entered ODT mode (see the SET ODT command in Chapter 3),
CTRL/C returns to PASDBG> prompt level.
If you are at PASDBG>
prompt level on an RT-11 host, CTRL/C cancels PASDBG and returns
to the RT-11 monitor.
On an RSX-llM/M-PLUS host, typing two
CTRL/Cs aborts the debugger and returns
control
to
the
RSX-llM/M-PLUS operating system.
CTRL/Y
On a VAX/VMS host system, interrupts PASDBG execution and returns
to the VMS operating system.
CTRL/O
Supresses screen output until the current
completes or until you type another CTRL/O.

PASDBG

command

HELP

Provides an on-line HELP facility that provides information about
PASDBG commands and qualifiers.

SPAWN

On an RSX-llM/M-PLUS or VAX/VMS host system, allows you
execute a single-line host command without exiting PASDBG.

2.2

REAL-TIME DEBUGGING

This section describes the PASDBG commands that, in conjunction with
the general-purpose debugging commands described in Section 2.1, allow
you to debug real-time programs. These commands report on the "typed"
data structures in your application -- process control blocks (PCBs) ,
binary and counting semaphores, ring buffers, and packet queues
display the kernel-maintained process state queues, and list the
exception-handling process groups established in your application.
With these commands, you can determine at successive stages of
execution whether the state of the processes in your application
conforms to your expectations.
The following commands are used to
structures in MicroPower/Pascal:

debug

SHOW PCB
SHOW SEMAPHORE
SHOW RING BUFFER
SHOW PACKET QUEUE
SHOW NAMES
SHOW FREE STRUCTURES
SHOW FREE PACKETS
SHOW INACTIVE QUEUE
SHOW READY/ACTIVE QUEUE
SHOW READY/SUSPENDED QUEUE
SHOW RUN QUEUE
SHOW EXCEPTION GROUPS
SHOW EXCEPTION

Version 1.5, February 1984

2-10

real-time

process

control

DEBUGGING TECHNIQUES
2.2.1

Typed Data Structure Display

Typed data structures are system data structures that are created and
deleted by processes, via primitive operations. The SHOW PCB, SHOW
SEMAPHORE, SHOW RING BUFFER, and SHOW PACKET QUEUE commands display
information about the following typed data structures: the process
control block (PCB), the binary semaphore, the counting semaphore, the
ring
buffer,
and
the packet queue.
(See Chapter 2 of the
MicroPower/Pascal Runtime Services Manual for a detailed description
of typed data structures.)

Version 1.5, February 1984

DEBUGGING TECHNIQUES
The SHOW PCB command displays information contained in the process
control block for the process you specify. This information describes
MicroPower/Pascal
system
the relation of the process to
the
environment.
Use the SHOW PCB command to determine the state of one or more
processes in an application. By issuing a SHOW PCB command for all
processes, you can determine the current status of the entire
application program.
The SHOW PCB command displays the process's name, serial number,
state, priority, suspend count, termination address, exception class,
stack limits, context switch options, and PCB address. SHOW PCB also
displays
the
exceptions
handled
by
the
process
and
the
exception-handler address for the process. If the process is blocked,
SHOW PCB displays the name, address, and serial number of the control
structure on which the process has blocked.
Note that depending on the current state and options used when you
created the process, PASDBG may not display some of the SHOW PCB
information.
The SHOW SEMAPHORE, SHOW RING BUFFER, and SHOW PACKET QUEUE commands
indicate the state of the control variable associated with the
specified structure and list any processes currently waiting for a
change in the variable.
SHOW SEMAPHORE displays the value of the
semaphore, and SHOW RING BUFFER displays the number of bytes currently
in use in the buffer.
Processes waiting on a semaphore or a ring
buffer are "blocked" and are held on the packet queue. To run, these
processes require a change to the control variable from another
process or interrupt service routine (ISR). Therefore, to determine
all the processes in a blocked condition, you must use the SHOW
SEMAPHORE, SHOW RING BUFFER, and SHOW PACKET QUEUE commands to examine
all the existing control variables. Alternatively, you can use SHOW
PROCESS/ALL or SHOW PCB to examine all the existing processes.
A packet queue is a MicroPower/Pascal control structure that receives
packets of information from processes that signal it. The information
is delivered to the process waiting on the packet queue.
Packet
queues can be priority or FIFO (first in, first out) ordered for both
packets and processes on the queue. With FIFO ordering, the processes
and/or packets leave the queue in the order in which they entered.
With priority ordering, the highest priority process and/or packet
leaves the queue first.
Although named a queue, a packet queue functions in the same manner as
a semaphore.
Other queues in MicroPower/Pascal are process state
queues created by the kernel during the program's initialization;
only one copy of each state queue exists. Semaphores and packet
queues are created by user program commands, and many of each type may
exist.
The SHOW NAMES, SHOW FREE STRUCTURES, and SHOW FREE PACKETS commands
provide information about kernel data structures in your application.
SHOW NAMES lists all the current named data structures.
SHOW FREE
STRUCTURES displays the amount of memory available for new kernel
structures. SHOW FREE PACKETS displays the number of unused packets
in the kernel packet pool.

2-11

DEBUGGING TECHNIQUES
SHOW PCB
Displays information stored in the process control block for the
process you specify.
Depending on the argument you give, SHOW
PCB lists information about the currently set process or a
particular process.
SHOW SEMAPHORE
Displays information about a semaphore, including the semaphore
type -- binary or counting -- a list of processes blocked on the
semaphore, the ordering of the waiting-process list
(FIFO or
priority ordered), and the state of the semaphore variable.
SHOW RING BUFFER
Displays information about a ring buffer, including its size, a
list of processes waiting for characters from the ring buffer, a
list of processes waiting for space to enter characters into the
ring buffer, the ordering of the waiting-process lists (FIFO or
priority ordered), and the number of bytes in the buffer.
SHOW PACKET QUEUE
Displays information about a packet queue, including a list of
processes blocked on the packet queue, a list of the packets
waiting on the queue and their priorities, and the ordering of
the waiting-process list and the packet list (FIFO or priority
ordered).
SHOW NAMES
Displays a list of all the currently named kernel structures,
including PCBs, semaphores, ring buffers, and packet queues.
SHOW FREE STRUCTURES
Displays the amount of memory that is left in the kernel
free-memory pool for new kernel s~ructures. You can use this
command to keep track of the kernel pool as structures are
created and destroyed.
SHOW FREE PACKETS
Displays the number of unused packets in the kernel packet pool.
You can use this command to determine whether your configuration
file allocated enough packets.

2.2.2

State Queue Display

The SHOW RUN QUEUE, SHOW READY/ACTIVE QUEUE, SHOW READY/SUSPENDED
QUEUE, and SHOW INACTIVE QUEUE commands display information about
processes on the kernel-maintained state queues.
The run queue
contains
the
active process.
The ready/active queue contains
processes that are waiting to enter the run queue;
they are there
because their priority is not higher than the priority of the running
process. Processes on the ready/suspended queue have been suspended
either by themselves or by another process; they will enter the
ready/active queue when another process issues them a RESUME.
The
inactive queue contains processes that have aborted with fatal
exceptions
exceptions for which no exception
handling
was
established.

2-12

DEBUGGING TECHNIQUES
There are no commands for changing the contents of a queue.
SHOW RUN QUEUE
Lists the currently running process.
this queue at any one time.

Only one process can be

SHOW READY/ACTIVE QUEUE
Lists the processes that are waiting to enter the run queue.
SHOW READY/SUSPENDED QUEUE
Lists the processes that have been suspended by themselves or by
another process.
These processes are waiting
for a RESUME
command from another process.
SHOW INACTIVE QUEUE
Lists the processes that have aborted with fatal exceptions.

2.2.3

Exception-Handling Display

The SHOW EXCEPTION GROUPS command displays current information about
exception handling
in your program.
Refer to Section 2.3.7 and
Chapter 3 for more information on exception handling with PASDBG.
The SHOW EXCEPTION command displays the last exception message
generated by the application and sent to the host. You cannot use
this command after execution has been restarted.
SHOW EXCEPTION GROUPS
Displays a list of the process
groups
with
established
exception-handling processes.
The command also lists the types
of exceptions that are handled for each process group and the
packet queue that is signaled when one of the listed exceptions
occurs in one of the listed process groups.
SHOW EXCEPTION
Displays the last exception message generated by the target and
sent to the host system -- if no GO command was issued in the
interim.

2.2.4

Real-Time Debugging Aids

This section lists real-time debugging commands that do not fit
any of the categories covered in Sections 2.2.1 through 2.2.3.
also Section 2.1.5.

into
See

SHOW TARGET
Displays the current state of the application system,
including
the physical
location at which the application system has
stopped, the instruction it is about to execute,
the currently
running process,
and whether or not the program is using memory
management on the target.
SET ODT
Forces the application system to halt and enter Micro-ODT mode.
All further entries are
interpreted as commands to the target
computer's Micro-ODT (refer to Section 2.3.6).

2-13

DEBUGGING TECHNIQUES
2.3

DEBUGGING HINTS

This section presents practical hints and suggestions to keep in
as you use PASDBG.

2.3.l

mind

Real-Time Errors

It can often be difficult to distinguish between time-independent and
real-time errors, especially when the error does not show an obvious
pattern. This section presents some ideas on how you can use PASDBG
to locate and analyze real-time errors.
To isolate these errors, begin by examining the state queues -- for
example,
run,
ready/active,
ready/suspend -- and
the
control
mechanisms -- for example, ring buffers and semaphores. Look for an
impossible combination of events based on the expected process
synchronization.
Another clue can often be found by varying the code execution speed.
Set the T-bit ON all the time -- with SET WATCH or STEP -- run the
program, and see if the problem disappears. Check the states of all
the processes when, or just before, the problem occurs. It may be
helpful to set a watchpoint on the kernel variable $RUN; this causes
the application to stop whenever the running process changes.

2.3.2

Critical Sections

The critical-section problem is one of the basic errors that occurs in
real-time programming environments.
Critical-section problems are
eliminated by exclusive use of MicroPower/Pascal control structures.
Figure 2-1 gives an example of a critical-section problem.
[ SYSTEM(MICROPOWER) ] PROGRAM FUBAR;
VAR A : INTEGER;
INUSE : BOOLEAN;
[PRIORITY(l00)] PROCESS ONE;
BEGIN
WHILE INUSE DO;
INUSE := TRUE;
A := l;
!NUSE := FALSE;

END;
[PRIORITY(l00)] PROCESS TWO;
BEGIN
WHILE INUSE DO;
INUSE := TRUE;
A := 2;

!NUSE := FALSE;
END;
BEGIN

{MAIN PROGRAM}

ENO.
Figure 2-1

Program Example Using Flags for Process Control

2-14

DEBUGGING TECHNIQUES
Assume that the two processes in the program example are set
to
depending on the receipt of different interrupts by the system.
sequence of events that causes the error is as follows:

run
The

Process ONE executes.

After executing WHILE !NUSE and before
TRUE, process ONE is interrupted.

Process TWO now starts running in response to the interrupt.

Process TWO executes into its main body of code (near A := 2).

Another interrupt or

Process ONE resumes execution.

Depending on whether or not process TWO completed statement
A := 2,
the eventual state of A can be either 1 or 2 because
process TWO will eventually resume execution at the point
where
it was interrupted.
Thus, the state of variable A is
indeterminate.

si~nificant

executing

!NUSE

event occurs.

The key to avoiding critical-section problems is to make sure that the
test and the set of each process -- that is, WHILE !NUSE DO and !NUSE
:=TRUE, in this case -- cannot be interrupted.
You could attempt to
solve this problem by combining the two statements into one.
Even if
the two statements could be combined, however, the compiler may expand
the statement into several machine-language
instructions, and the
problem could reappear.
Rather, the best solution is always to use
MicroPower/Pascal control structures such as semaphores, because they
cannot be
interrupted.
Interrupts that change
the
state
of
MicroPower/Pascal's access
to the control structures are queued;
no
semaphore can be changed
until
any previously started primitive
operation is complete.
Figure 2-2 shows that the error disappears if
the program is written using
a
binary semaphore,
the most simple
MicroPower/Pascal control structure.
[ SYSTEM(MICROPOWER) ] PROGRAM FUBAR;
VAR A : INTEGER;
!NUSE : SEMAPHORE DESC;
D : BOOLEAN;
[PRIORITY(l00)] PROCESS ONE;
BEGIN
WAIT(DESC := !NUSE);
A

:= 1;

SIGNAL(DESC := INUSE);
END;
[PRIORITY(l00)] PROCESS TWO;
BEGIN
WAIT(DESC := INUSE);
A

:= 2;

SIGNAL(DESC := INUSE);
END;
BEGIN

{MAIN PROGRAM}
D := CREATE_BINARY_SEMAPHORE(DESC := !NUSE);

END.
Figure 2-2

Program Example Using Semaphores for Process Control
2-15

DEBUGGING TECHNIQUES
2.3.3

Race Conditions

Race conditions are another cause of real-time errors.
In a race, two
program
elements
attempt to use the same resource or device
simultaneously. MicroPower/Pascal control structures are designed to
avoid these race conditions and to make those that do occur easy to
find and correct.
Four examples of race conditions are described below.

2.3.4

Deadlocks Two processes require the use of the same two
resources.
One process locks into the first resource, and
another process locks into the second resource.
Each process
then attempts to access the other resource without giving up
the resource it already owns. The result
is that neither
process can continue operating.

Data Juxtaposition Two processes request data from the same
device without identifying themselves as the source of the
request.
The data, therefore, can be returned to the wrong
process.
For example, process A submits a disk read request
and then stops. Process B then starts and submits its own
read
request, which is queued behind A's request. Process B
sees the done flag from the disk and reads the information
gathered
for process A.
Process B then does something
indeterminate because it has the wrong
information;
if
process A then executes, it would make the same mistake as B
did, because it would read the information gathered for
process B.

Unprotected Protection Controls Flags can be set to protect
critical sections of code, often causing the flags to become
critical sections.
If a process does not set the proper
types of flags in the proper order,
the process may be
interrupted by false signals caused by the improperly set
flags.
MicroPower/Pascal process control variables are
designed to avoid this type of problem.

Insufficient Processing Time
(This is a race condition in
reverse.)
The following
example describes an insufficient
processing
time problem caused when an external device
streams a high rate of interrupts to a processor. The
processor responds to the
incoming
interrupts with
an
interrupt service routine (!SR).
If the ISR does not disable
further interrupts then the ISR cannot complete execution
before the next interrupt arrives.
If the ISR disables
interrupts then interrupts are lost.
In the first case,
the
system is likely to crash because of the excessive number of
ISRs queued to handle the interrupts or because one interrupt
scrambles another interrupt's data.
In the second case, data
is lost because the flow of interrupts is cut off.

STEP and WATCH Commands

The STEP and
appropriate.

WATCH

commands

run

2-16

slowly.

Use

them

only

when

DEBUGGING TECHNIQUES
2.3.5

SET WATCH with Local Variables

To set a watchpoint on a local variable in a process other than the
static process, you must SET PROCESS to the process that contains the
local variable. However, if the process has not been called or the
routine containing the variable has not executed, the local variable
does not yet exist. Until the process is called and the routine
executes, you cannot set a watch on the variable; nor can you examine
it.
Furthermore, if you set watch on a local variable and the process in
which you set the watchpoint terminates, the process's stack space for
local variables is released, but the watchpoint is still set on the
old stack location.
If another copy of the process is then called,
new copies of the variables are created on the stack.
A watchpoint
set on a variable in the previous invocation is now set on an unknown
variable in the new invocation -- assuming the stack was allocated in
the same area.
The watchpoint, under these circumstances, first
points to the variable, then points to nothing, then points to
something unknown.
To use the SET WATCH command on a local variable, do the following:
1.

Set a breakpoint on the first line of code in the routine.

When that breakpoint is triggered, set your watchpoint.

Before restarting, set a breakpoint on any termination
in the process.

point

If you wish, cancel
point.

entry

Continue debug9ing.

When a termination point breakpoint triggers, cancel all
watchpoints for the routine.

If you canceled the entry point breakpoint (step 4)
and you
wish to set the watch again if the process is restarted,
repeat from step 1.

the

breakpoint

the

process

the

You can set breakpoints on a process that has not yet been created.
In fact, you can perform all manipulations involving code locations,
because the code for the process always physically exists.
Use the
SET PROGRAM and the SET SCOPE commands -- not SET PROCESS -- to gain
access to the static components of the not yet created process.

2.3.6

Micro-ODT (uODT) Mode

If the target system halts while you are
enters Micro-CDT
(uODT) mode.
PASDBG
displays the following message:

using PASDBG,
the system
senses this transition and

?PASDBG-E-TARHALT, Target halted - PASDBG in uODT mode
@

2-17

DEBUGGING TECHNIQUES

NOTE
The @ symbol displayed is the Micro-CDT
prompt.
Note that this is the only
situation in which PASDBG prints the @
symbol.
All other occurrences of the @
symbol are limited to commands you type.
The @
symbol
and
all
subsequent
Micro-ODT
dialog
are
displayed in
reverse video.
If you are using a
terminal that does not respond to VT100
escape sequences for
reversing
the
video, extraneous characters preceding
the @ symbol will be displayed.
You can now use Micro-ODT as if your terminal were directly connected
to the application so that you can obtain additional debugging
information. All commands typed at the host system console terminal
are sent to the target system as Micro-ODT commands, and the target
system response is displayed on the terminal. See the Microcomputer
Processor Handbook for instructions on how to use Micro-ODT.
exit from Micro-ODT dialog, type CTRL/C or CTRL/A. Control returns
I To
to PASDBG, which will then respond to user commands; however, the
target system remains halted and in Micro-ODT mode.
The target system Micro-ODT can also be entered by typing the S~T ODT
command to PASDBG.
See the SET ODT section of Chapter 3 for details.

2.3.7

Fatal Exceptions

If a fatal exception is raised by the application program while you
are debugging, the offending process is aborted and the exception is
reported to PASDBG.
If the exception was raised by the kernel, PASDBG
prints:
FATAL KERNEL TRAP address
In this message, "address" is the address of the instruction after the
one that caused the fatal trap.
If the exception was raised by main-line Pascal code, by the Pascal
object-time system (OTS), or by any other nonkernel code, PASDBG
reports the class and subcode of the exception, the physical and
virtual address of the instruction that caused the exception, and the
value of the PC after the exception was detected.
If the exception
was raised by Pascal code or the OTS, PASDBG also reports the nwnber
of the statement that caused the exception.
Any attempt to continue program execution after a fatal exception has
been raised may produce unpredictable results unless the application
was specifically designed to allow the offending process to terminate
without disruption of the application.

Exception codes are listed in the MicroPower/Pascal messages manual
for your host system. Exception handling is discussed in detail in
the MicroPower/Pascal Runtime Services Manual, Chapter 7, and in the
MicroPower/Pascal Language Guide, Chapter 17.

Version 1.5, February 1984

2-18

DEBUGGING TECHNIQUES

2.3.8

Debugging FALCON or FALCON-PLUS Applications

PASDBG is used to debug SBC-11/21 applications in essentially the same
manner as with any other MicroPower/Pascal application. However,
because the SBC-11/21 does not provide Micro-CDT, the console emulator
required by PASDBG, Macro-CDT -- a Micro-CDT emulator contained on the
KXT11-A2 PROM set -- must be added to the SBC-11/21 board.
The
Macro-CDT program performs the following functions for the SBC-11/21
processor:
power-up, bootstrap, down-line load, halt and break
intercepts, trap-to-4 emulation, and power-up diagnostics.
All SBC-11/21 configurations can be used
with
PASDBG.
Some
configurations, however, require that the SBC-11/21 be turned off,
restarted, and initialized by Macro-CDT each time the application is
loaded.
This
"cold-start"
procedure
is necessary for those
configurations that either use nonstandard BREAK jumpers or specify a
SYSHALT parameter other than ODTROM in the configuration file.
In
these cases, the break sent by PASDBG will cause the SBC-11/21 to hang
rather
than
to
enter
Macro-CDT.
Otherwise, if you specify
SYSHALT+ODTROM, the application program can be reloaded without
repeating the cold start.
All PASDBG commands function normally with the SBC-11/21.
The
application cannot, however, service any interrupt signals while WATCH
or STEP is set, because the SBC-11/21 processor does not allow
interrupts to be processed when the T-bit is set on, and PASDBG uses
the T-bit to perform the WATCH and STEP functions.
Therefore, you
must be careful of where and how WATCH and STEP are used with
SBC-11/21
applications,
especially
when
you
are
debugging
time-dependent programs.

2.3.9

Debugging KXTll-C Arbiter/Slave Protocol Transactions

The MicroPower/Pascal kernel defines two debug locations -- $KXTQW and
$KXTQR -- that can be used to debug KXTll-C arbiter/slave protocol
transactions.
{The KXTll-C arbiter/slave protocol is implemented via
the KX handler running on the arbiter system and the KK handler
running on the KXTll-C peripheral processor.)
The kernel-defined debug location $KXTQW is called by the KK handler
just before data from the arbiter is transferred from a channel into a
KXTll-C buffer -- a KX handler write operation.
The kernel-defined debug location $KXTQR is called by the KK handler
after data has been transferred from a KXTll-C buffer to a channel but
before the LSI-11 bus is interrupted -- a KX handler read operation.
You can use the PASDBG SET BREAK command to set a breakpoint on either
or both of the debug locations. Doing so allows you to examine a
segment of a message while a read/write operation is suspended in
midexecution.

Version 1.5, February 1984

2-19

CHAPTER 3
COMMAND REFERENCE

This chapter provides information about debugger command format,
parameters, and qualifiers for quick reference.
Sections are ordered
alphabetically by command name.
NOTE
In this chapter,
underscores
indicate
the
minimum
acceptable
abbreviations for debugger commands and
qualifiers.
For example, the command
SHOW PCB appears as SHOW PCB.
Other
notational
conventions used in this
chapter are listed in the Preface.
The following operator symbols are used in debugger commands:
Symbol

Description

@
%

Indirect file-specification prefix
Radix keyword prefix
Command modifier prefix
Scope modifier prefix
Comment pref ix
Parameter list separator
End of line delimiter
Address range specification
Literal file specification
Breakpoint ordinal number prefix

I
\
<CR>
'<filespec>'
#

3-1

COMMAND REFERENCE

3.1

PASDBG accepts commands from an indirect command file. To invoke an
indirect command file, type @ followed by the file name.
PASDBG
displays the commands from the file and the debugger's response, if
any, one command at a time.
Note that the LOG command can be used to generate
use with @.

command

files

for

NOTE
To exit from
end-of-file
CTRL/C.

an indirect file before
has
been reached, type

Syntax
@ [dev:] name[ .ext]

Command Parameters
dev
The name of the host-system device containing the indirect file.
name
The indirect file's name.
ext
The indirect file's extension.

The default extension is .COM.

Example
PASDBG>@setup<RET>

!execute commands from setup.com
NOTE

Do not confuse the operator symbol @
with the prompt@. The prompt@, shown
in reverse video, indicates that PASDBG
has entered Micro-ODT mode.
If the
application
system
crashes,
PASDBG
enters Micro-ODT mode and issues the
statement:
%PASDBG-E-TARHALT Target halted PASDBG in uODT mode
@

Version 1.5, February 1984

3-2

COMMAND REFERENCE
In Micro-ODT mode,
PASDBG
connects
directly to the Micro-ODT facility on
the application system.
The
PASDBG
terminal now functions as if it were a
terminal on the application system in
Micro-ODT.
For information on how to
use Micro-ODT to
gather
additional
debugging
information,
consult
the
Microcomputer Processor Handbook.

3-3

COMMAND REFERENCE

CANCEL BREAK

3.2

CANCEL BREAK

The CANCEL BREAK command removes either a particular breakpoint or all
breakpoints.
You can cancel a particular breakpoint by specifying the breakpoint
number,
statement number, label number, or address of the breakpoint.
If you are not sure of the ordinal number of a breakpoint, use the
SHOW BREAK command to list all currently set breakpoints and their
numbers.
If you specify the /ALL switch, PASDBG
set.
To verify the
command.

cancellation

will

cancel

breakpoint,

Syntax
Jaddress-expression}

CANCEL ~REAK[/ALL]

[

use

all

breakpoints

the

SHOW

BREAK

~breakpoint-number

Command Parameters
address-expression
An expression giving the location of the breakpoint to
canceled. Address-expressions may be one of the following:

(unsigned

•

statement-number
a Pascal statement
integer) valid within the current scope.

•

LABEL label-number -- a Pascal label number (unsigned integer)
defined within the current scope, preceded by the keyword
"LABEL" and a space.

•

MACRO-global-name -- the name of a MACR0-11 global symbol
defined in the current program. Dots ( ". ") in the symbol name
must be entered as underscores (" "):
for example, PC.LNK is
entered as PC LNK.
-

•

@[radix]address -- a physical, kernel, or virtual address
preceded by an at sign and an optional radix indicator. The
four radix
indicators are % (octal),
%0
(octal),
%X
(hexadecimal), and %0 (decimal). The address is interpreted
as a physical address if physical mapping is set, a kernel
address if KERNEL mapping is set, or a virtual address in the
currently set process if process mapping is set.

number

breakpoint-number
The ordinal number of the breakpoint to be canceled.

Command Qualifier
/ALL
Specifies that all breakpoints are to be canceled.
Version 1.5, February 1984

3-4

COMMAND REFERENCE
Examples
PASDBG>cancel break l<RET>

!Cancels breakpoint at statement
!number 1 in the current scope.

PASDBG>cancel break l2<RET>

!Cancels breakpoint number 2.

PASDBG>cancel break LABEL 19<RET>

!Cancels the breakpoint set
!at label 10.

PASDBG>cancel break @%921354<RET>

!Cancels the breakpoint set
!at octal location 021354.

3-5

COMMAND REFERENCE

CANCEL PROCESS
3.3

CANCEL PROCESS

The CANCEL PROCESS command cancels the process selected with SET
PROCESS, cancels the scope selected with SET SCOPE, and performs a SET
PROCESS to the program set with SET PROGRAM.
If no SET PROGRAM was
issued, PASDBG sets physical addressing only.
The CANCEL PROCESS command has no arguments.
Syntax
CANCEL PROCESS
Example
PASDBG>show proc<RET>
Process 14, (no name), PCB at KERNEL (022416)
PASDBG>cancel proc<RET>
Current process set to:
Process 3, name= 'PROCSl', PCB at KERNEL (021620)
Scope set to:
Program PROCSl, Module PROCSl

3-6

COMMAND REFERENCE

CANCEL SCOPE

3.4

CANCEL SCOPE

The CANCEL SCOPE command revokes the current lexical scope setting.
No scoped Pascal data or code references are allowed until a new scope
is set. Program and module settings remain in effect after CANCEL
SCOPE.
The command has no arguments.

Syntax
CANCEL SCOPE

Example
PASDBG>show scope<RET>
Program PROCS2, Module PROCS2, Scope: Pl
PASDBG>cancel scope<RET>
PASDBG>show scope<RET>
Program PROCS2, Module PROCS2

3-7

COMMAND REFERENCE

CANCEL STEP
3.5

CANCEL STEP

The CANCEL STEP command restores the SET STEP
STATEMENT, INTO. The command has no arguments.
Syntax
CANCEL STEP
Example
PASDBG>show step<RET>
Step parameters:

instruction into

PASDBG>cancel step<RET>
PASDBG>show step<RET>
Step parameters:

statement into

3-8

default

para~eters:

COMMAND REFERENCE

CANCEL TRACE
3.6

CANCEL TRACE

The CANCEL TRACE command cancels either a
currently set tracepoints.

single

tracepoint

all

To cancel a single tracepoint, you must specify the address of the
tracepoint,
its ordinal number,
its label number, or its statement
number.
If you are not sure of the ordinal number of a
tracepoint,
use the SHOW TRACE command to list all currently set tracepoints and
their numbers.
To cancel all current tracepoints, use the /ALL qualifier.
To verify the
comma.nd.

cancellation

tracepoint,

use

the

SHOW

TRACE

Syntax
address-expression}]
CANCEL TRACE [/ALL]
~
~
[ {#tracepoint-number

Command Parameters
address-expression
An expression giving the location of the tracepoint to
canceled. Address-expressions may be one of the following:
number

(unsigned

•

statement-number
a Pascal statement
integer) valid within the current scope.

•

LABEL label-number -- a Pascal label number (unsigned integer)
defined within the current scope, preceded by the keyword
"LABEL" and a space.

•

MACRO-global-name -- the name of a MACR0-11 global symbol
defined in the current program. Dots (".") in the symbol name
must be entered as underscores ("_");
for example, PC.LNK is
entered as PC LNK.

•

tracepoint-number
The ordinal number of the tracepoint to be canceled.

Command Qualifier
/ALL
Specifies that all tracepoints are to be canceled.

Version 1.5, February 1984

3-9

COMMAND REFERENCE
Examples
PASDBG>cancel trace 12<RET>

!Cancels tracepoint number 2

PASDBG>cancel trace LABEL 2<RET> !Cancels the tracepoint set at
!label 2

3-10

COMMAND REFERENCE

CANCEL WATCH
3.7

CANCEL WATCH

The CANCEL WATCH command removes either a particular watchpoint or all
watchpoints.
You can cancel a particular watchpoint by specifying either the
watchpoint number or address of the watchpoint.
If you have two
watchpoints set to the same location, you should use the ordinal
numbers of the watchpoints to cancel one or both of them.
If you are
not sure of the ordinal number of a watchpoint, use the SHOW WATCH
command to list all currently set watchpoints and their numbers.
If you specify the /ALL switch, PASDBG
set.
To verify the
command.

cancellation

will

cancel

watchpoint,

use

all

watchpoints

the

SHOW

WATCH

Syntax
dd ress-expr ess ion}]
CANCEL WATCH[/ALL]
~
~
#watchpoint-number
[{
Command Parameters
address-expression
An expression giving the location of the watchpoint to
canceled. Address-expressions may be one of the following:

•

variable-name -- the name of a Pascal variable defined within
the current scope. Structure names are prohibited. However,
you can specify a record field or an array element if it is a
simple type.

•

MACRO-global-name -- the name of a MACR0-11 global symbol
defined in the current program. Dots (". "} in the symbol name
must be entered as underscores (" "); for example, PC. LNK is
entered as PC LNK.
-

•

@[radix]address -- a physical, kernel, or virtual address
preceded by an at sign and an optional radix indicator.
~he
four radix indicators are % (octal),
%0
(octal),
%X
(hexadecimal), and %D (decimal). The address is interpreted
as a physical address if physical mapping is set, a kernel
address if KERNEL mapping is set, or a virtual address in the
currently set process if process mapping is set.

watchpoint-number
The ordinal number of the watchpoint to be canceled.
Command Qualifier
/ALL
Specifies that all watchpoints are to be canceled.

Version 1.5, February 1984

3-11

COMMAND REFERENCE

Examples
PASDBG>cancel watch ll<RET>

!Cancels watchpoint number 1

PASDBG>cancel watch @%021354<RET> !Cancels the watchpoint set
!at octal location 021354

3-12

COMMAND REFERENCE

CLOSE
3.8

The CLOSE command closes an open log file.
the command has no effect.

If no log

Syntax
CLOSE [LOG]

Command Parameter
LOG
Has no effect;

it is included for clarity.

3-13

file

open,

COMMAND REFERENCE

CTRL/C

3.9

CTRL/C

The CTRL/C command (hold down the CTRL key while typing C) can be used
to stop the application program, to abort a PASDBG command or command
procedure, to exit from Micro-CDT mode, or, on an
RT-11
or
RSX-llM/M-PLUS host, to exit from PASDBG.
If the application is running,
returns to PASDBG> prompt level.

CTRL/C

stops

the

application

and

If a PASDBG command or a command procedure is executing, CTRL/C aborts
the command or command procedure and returns to PASDBG> prompt level.
If the debugger is in Micro-ODT mode (see the SET ODT command) , CTRL/C
terminates the ODT dialog and returns to PASDBG> prompt level.
If CTRL/C is typed at the PASDBG> prompt level on an RT-11
PASDBG is canceled, and control returns to the RT-11 monitor.

host,

On an RSX-llM/M-PLUS host, typing two CTRL/Cs aborts the debugger
returns control to the RSX-llM/M-PLUS operating system.

and

Syntax

CTRL/C

Version 1.5, February 1984

3-14

COMMAND REFERENCE

DEPOSIT
3. 11

DEPOSIT

The DEPOSIT command changes the
memory location, or a register.

contents

Pascal

variable,

To deposit into 2 Pascal variable, set program, process, and scope to
the routine containing the variable.
You can then modify the
variable, referring to it by its Pascal name and specifying a value to
replace its current value -- for example, dep r = 1.1.
In most instances, the type of the data you specify should match the
type of the variable you are modifying. However, PASDBG permits you
to deposit data into a variable without regard to type, so long as the
data size is not larger than the variable size.
The application
program will then interpret the data as if it were of the type defined
in the source code. For example, a DEPOSIT of the character 'A' into
an integer variable would force the ASCII value of the character
(65
decimal) into the variable.
You can deposit up to four bytes of character data or real data with
one command.
In the case of character data, you can deposit a string
of up to four characters.
Note, however, that since data size cannot
exceed variable size, you cannot deposit a 4-character string into a
Pascal character variable, but only into a Pascal real variable or a
specified address.
In the case of real data, you can deposit one r~al
nmnber.
(All real nmnbers are four bytes long.) If you deposit a real
nmnber into a register,
PASDBG deposits the two low bytes into the
specified register and the two high bytes into the next higher
register.
NOTE
For your protection,
PASDBG does not
permit deposits into R6 or R7 (the stack
pointer and the program counter) •
If you deposit into a PACKED variable,
packs the new data into the variable.

the

debugger

automatically

DEPOSIT/BYTE deposits a byte of data at a specified address.
You must
use the /BYTE option to deposit data into an odd-nmnbered address.
DEPOSIT/BYTE can also be used to deposit three bytes of character data
(see the examples below) .
You cannot deposit into a local variable in a process or a procedure
that has not yet been invoked.
Nor can you deposit into a label or a
statement.
Syntax
QEPOSIT[/BYTE] {

add ress-e. xpression}

Version 1.5, February 1984

reg 1ster

3-16.1

[:]= [radix]data

COMMAND REFERENCE

Command Parameters
address-expression
An
expression
specifying
a
location
to
Address-expressions may be one of the following:

modified.

•

variable-name -- the name of a Pascal variable defined
the current scope. Set names are prohibited.

within

•

MACRO-global-name -- the name of a MACR0-11 global symbol
defined in the current program. Dots (".") in the symbol name
must be entered as underscores (" ");
for example, PC.LNK is
entered as PC LNK.
-

•

@[radix]address -- a physical, kernel, or virtual address
preceded by an at sign and an optional radix indicator. The
four radix indicators are % (octal),
%0
(octal),
%X
(hexadecimal) , and %D (decimal). The address is interpreted
as a physical address if physical mapping
is set, a kernel
address if KERNEL mapping is set, or a virtual address in the
currently set process if process mapping is set.

radix
Any of the following:
%D -- decimal;
%
or
%0 -- octal;
%X -- hexadecimal.
Radix can only be used with unsigned integer
data.
data
One of the following value representations: an integer; a real
number;
a character string;
or a symbolic value, such as
TRUE/FALSE or an enumerated type constant.
If you are depositing
into a variable, the data size must not exceed the variable size.

Command Qualifier
/BYTE
Instructs PASDBG to deposit one byte of data at the specified
address.
Alternatively, if the data specified is a 3-byte
character string, PASDBG will deposit three bytes of data at the
specified address.

Examples
DEPOSIT a[2]:=2

!Deposits decimal 2 into Pascal
! variable a [2] (part of an array
! cal led a) •

DEP DOOR = RED

!Deposits RED into a Pascal variable
!DOOR, which is an enumerated type
! (such as RED, GREEN, MAGENTA,
!CANDYSTRIPE)

DEP SWITCH := TRUE

!Deposits TRUE into the Boolean
! variable SWITCH

DEPOSIT @%199:=%19

!Deposits octal 10 into octal location
!100 (bytes 100 and 101)

version 1.5, February 1984

3-17

COMMAND REFERENCE
DEPOSIT/BYTE @%17759l='A'

!Deposits the character A in octal
!byte 177501. Byte 177500 is not
!affected.

DEPOSIT @299:=1.7E-92

!Deposits decimal l.7E-02 into decimal
!locations 200 and 202 (bytes 200,
!201, 202, and 203).

DEPOSIT %R2 = %23

!Deposits octal 23 into register 2.

DEPOSIT @%177599 ='ABC'

!Deposits four characters into
!consecutive memory locations starting
!with octal location 177500, zero
!filling byte 177503.

DEPOSIT/BYTE @%177699='ABC'

!Deposits three characters into
!consecutive memory locations starting
!with octal location 177600, leaving
!byte 177603 untouched.

DEPOSIT A[l] = Blue

!Correct array form.
Deposits Blue
!into A[l] of array Colors.

DEPOSIT Employee.age:=39

!Deposits 30 into the field age of
!record Employee.

3-18

COMMAND REFERENCE

EXAMINE

3.12

The EXAMINE command displays, on the console terminal, the contents of
a specified location, register, statement, or variable -- or a range
of locations, registers, or statements -- in the target system.
When you use the EXAMINE command to look at a MicroPower/Pascal
variable, PASDBG knows the type of the variable and displays the
variable in the appropriate format.
In multilevel variables, such as
records or arrays, PASDBG displays all fields subordinate to the
specified name.
You can use the EXAMINE command to disassemble a Pascal
range of statements. See the Examples section below.

statement

You cannot examine a local variable in a procedure that has not yet
invoked or a process that has not yet initialized. You also cannot
examine the priority or other attribute of a process that has not yet
initialized.
Syntax

addr-expr[ •• addr-expr]}
!XAMINE[/qualifier[/qualifier]]

{ register[ •• register]

Command Parameters

addr-expr
An expression specifying a location
parameter may be one of the following:

examined.

(unsigned

•

statement-number
a Pascal statement
integer) valid within the current scope.

•

variable-name -- the name of a Pascal variable defined within
the current scope.
Set names are prohibited. Also, Pascal
variable names cannot be used in range specifications.

•

LABEL label-number -- a Pascal label number (unsigned integer)
defined within the current scope, preceded by the keyword
"LABEL" and a space.

•

MACRO-global-name -- the name of a MACR0-11 global symbol
defined in the current program. Dots (". ") in the symbol name
must be entered as underscores (" ");
for example, PC.LNK is
entered as PC LNK.
-

•

@[radix]address -- a physical, kernel, or virtual address
preceded by an at sign and an optional radix indicator.
The
four radix indicators are % (octal),
%0
(octal),
%X
(hexadecimal) , and %0 (decimal) • The address is interpreted
as a physical address if physical mapping
is set, a kernel
address if KERNEL mapping is set, or a virtual address in the
currently set process if process mapping is set.

Version 1.5, February 1984

3-19

number

This

COMMAND REFERENCE
register
A PDP-11 instr uc ti on register specification
%PC, %PS, or%R8).

%R7,

%SP,

correctly,

type

the

(%R0

Command Qualifiers
/WORD
Displays the data in word format.
/BYTE
Displays the data in byte format.
/ASCII
Displays the word in ASCII character format.
/!NSTRUCTION
Displays the data in PDP-11 instruction format.
/RAD50
Displays the word in RAD50 character format.
/REAL
Displays the data in floating point format.
/BINARY
Displays data in base 2.
/DECIMAL
Displays data in base 10.
/!!_EXADECIMAL
Displays data in base 16.
/QCTAL
Displays data in base 8.
Examples
Assuming that you have set program and scope
following to examine a variable called FOO:
PASDBG>examine f oo<RET>
(012345): 43
PASDBG displays the octal virtual address of the variable
in
parentheses and then displays the value of the variable. The data
type of the variable determines the display format that PASDBG uses.
PASDBG will not permit you to display the variable in a format that is
not valid for the variable (such as INSTRUCTION).
To display the
variable in another format,
specify the virtual address of the
variable.
If you examine an array or record, PASDBG will display the
elements and fields of the structure. For example:
PASDBG>examine/instr a<RET>
!display 4-element array
%PASDBG-W-Illegal use of mode switch -- ignored
A[l] (040000)
1
A[2] (040002)
2
A[3] (040004)
3
A[4] (040006)
4

3-20

individual

COMMAND REFERENCE

You could then examine the physical locations 40000 •. 40006 in any
other mode, if desired.
The warning indicates that PASDBG ignored the
/INSTRUCTION switch.

Version 1.5, February 1984

COMMAND REFEREN'CE
If you examine a Pascal statement, the debugger displays the first
PDP-11
instruction
generated
by the specified statement.
To
completely disassemble the statement, specify a range of statements.
For example:
EXAMINE 1 •• 2
Every PDP-11 instruction generated by statement 1 in the current scope
would be displayed, followed by the first PDP-11 instruction generated
by statement 2. To disassemble statements 1 and 2 in the current
scope, type:
EXAMINE 1 •• 3
You can examine a variable of an enumerated type such as:
TYPE DOOR= {RED,BLUE,POLKA-DOT,CHARTREUSE);
VAR KNOB : DOOR;
PASDBG will display the variable according to the defined values.
example:

For

PASDBG>EX KNOB<RET>
( 0 41 710} : RED
Boolean variables are displayed as TRUE or FALSE.
You may specify at most two switches in an EXAMINE command.
For
example,
to display octal locations 100 to 110 of the current program
as OCTAL BYTES, type:
EXAMINE/BYTE/OCTAL @'100 •• @%110
The % signs on the address numbers indicate that they have been
entered as octal addresses. The /OCTAL switch asks PASDBG to output
the contents of the locations as octal numbers.
To examine a register, specify %Rn, where R denotes a register, and n
is the register number (from 0 to 7).
'SP' is an alternate name for
R6, the stack pointer register;
'PC' is an alternate name for R7, the
program counter register; and 'PS' and 'RS' are alternate names for
the PSW (processor status word}.
For example, to display the contents
of R4 in octal, type:
EXAMINE/OCTAL %R4
To display in hexadecimal the contents of
inclusive, type:

registers

through

R6,

EXAMINE/HEX %R2 •• %SP
If you use /REAL with the EXAMINE command,
two registers are
displayed.
The specified
register becomes the low-order 16 bits of
the number; the next higher register becomes the high-order 16 bits.
Mapped system users note:
To access memory by its
issue a SET PHYSICAL command first.

physical

address,

Macro users note:
PASDBG displays the effective address for an
instruction that references the PC.
For example, PASDBG displays JMP
200(PC) as "JMP 304"· if the instruction is at location 100(octal).
The effective address is shown just as MACR0-11 assembled it, using
the program counter and the length of the instruction to determine
what the PC will be when that part of the instruction is executed.
3-21

COMMAND REFERENCE

EXIT

3.13

EXIT

The EXIT command terminates a PASDBG debugging session.
It does not
halt the application system but leaves it stopped. Control returns to
the host monitor. The EXIT command has no arguments.
To exit PASDBG and leave the
command.

application

Syntax
EXIT

3-22

running,

use

the

GO/EXIT

COMMAND REFERENCE

3.14

The GO command starts or continues the execution of the program that
you are debugging.
The first GO command starts the program at the
application program's starting point in the kernel.
Thereafter, GO
continues execution from the point at which that execution was
stopped. After issuing GO, PASDBG does not permit any commands except
a carriage return, which stops the application program. When the
processor stops for any reason, such as a carriage return or the
triggering of a breakpoint, PASDBG resets scope to the currently
running program, procedure, function, or process (if any), resets
process
to
the
currently running process (if any), displays
information on the state of the application, and returns to command
mode.
GO/EXIT instructs the debugger to exit to
starting or continuing program execution.

the

host

monitor

after

The GO command has no arguments.
Syntax
Q.O [/EXIT]
Command Qualifier
/EXIT
Instructs PASDBG to exit after
execution.

starting

continuing

program

Example
PASDBG>go<RET>
[Target execution resumed -- type <CR> to stop target]
<RET>
Target stopped at physical (00037204), virtual (037204)
R3,-(SP)
Executing non-Pascal code
Process 3, name= 'PROCS2', PCB at KERNEL (021626}

3-23

MOV

COMMAND REFERENCE

HALT

3.15

HALT

The HALT command stops the application system. When the program is
stopped, PASDBG displays information as if a breakpoint had occurred.
In most cases, typing HALT is not necessary, because PASDBG treats a
carriage return as a HALT command when the application system is
running.
The HALT command has no arguments.
Syntax
~LT

or
CTRL/C
or
<RET> (after you issued a GO command)
Example
PASDBG>halt<RET>
Target stopped at physical (00035002), virtual (035002)
34706

Executing non-Pascal code
Process 12, (no name), PCB at KERNEL (022272)

3-24

COMMAND REFERENCE

HELP

3.16

HELP

PASDBG provides an on-line HELP facility for all PASDBG commands. For
a list of commands, type HELP. For more information on a specific
command, type HELP command.
PASDBG may notify you that
more
information is available on a particular keyword -- a parameter or
qualifier -- used with the command you specified.
To get the
information, type HELP command keyword.
Syntax
HELP [command [keyword]]
Command Parameters
(no arguments)
If no argument is
specify.

given,

PASDBG

lists

the

commands

you

can

command
The name of a debugger command with which you need help.
keyword
A parameter
information.

qualifier

about

which

you

Example
PASDBG>help close<RET>
HELP
CLOSE
"CLOSE"
Closes a log file opened with the LOG command.

3-25

want

further

COMMAND REFERENCE

3.17

INIT

The !NIT command reinitializes the debugger's internal data base.
INIT cancels all breakpoints, tracepoints, and watchpoints; resets
scope, program\module, and process;
resets the step increments to
STATEMENT and INTO; and stops the application system, if necessary.
After reinitializing, PASDBG displays information on the state of the
application system and returns to command mode.
PASDBG performs an implicit !NIT at start-up time and when it executes
a LOAD command.
If you specify the RESTART switch on INIT, PASDBG reinitializes
application to its starting point and returns to command mode.

the

Syntax
!NIT [/RESTART]
Command Qualifier
/RESTART
Causes PASDBG to reinitialize the
point.

application

its

starting

NOTE

If any of the application code becomes
corrupted, using !NIT/RESTART will have
unpredictable results.
Target system RAM is not zeroed on
!NIT/RESTART.
The LOAD command must be
used for RAM to be zeroed.
Examples
PASDBG>go<RET>
[Target execution resumed - type <CR> to stop target]
** BREAKPOINT #0 'l PROCS2'
Target stopped at physical (00036654), virtual (036654)
@#43516 ,- (SP)
In statement 1 + 0 in
Program PROCS2, Module PROCS2, Scope: PROCS2
Process 3, name = 'PROCS2', PCB at KERNEL (021626)

MOV

PASDBG>init<RET>
Target stopped at physical (00036654), virtual (036654)
@#43516 ,-(SP)
In statement 1 + 0 in
Program PROCS2, Module PROCS2, Scope: PROCS2
Process 3, name= 'PROCS2', PCB at KERNEL (021626)

3-26

MOV

COMMAND REFERENCE
PASDBG>show break<RET>
;PASDBG-I-NONESET, None set
PASDBG>init/rest<RET>
Target stopped at physical (~0001534), virtual (001534)
@#5656
Executing KERNEL code
No process set, KERNEL mapping in effect

3-27

JMP

COMMAND REFERENCE

LOAD
3.18

LOAD

The LOAD command loads
PASDBG.

files

into

the

LOAD/TARGET down-line loads a copy of
(.MIM) file into the target system.

the

target

system

and/or

into

application

memory

image

LOAD/SYMBOL loads a copy of the application program's symbol table
(.DBG)
file into PASDBG on the host. You must issue this command to
access symbols with PASDBG.
Also, commands that require access to
kernel
symbols, such as SHOW RUN QUEUE, do not work without
LOAD/SYMBOL.
LOAD -- with no option and no file extension specified
PASDBG to perform both a LOAD/TARGET and a LOAD/SYMBOL.

directs

LOAD/EXIT down-line loads a copy of the application .MIM file into the
target system, starts the application, and then exits from PASDBG to
the host operating system. You use the LOAD/EXIT command to down-line
load an application built without debug support. The application then
executes on the target system independently of PASDBG.
(For RT users,
the
LOAD/EXIT
command
provides
an
alternative
to
the
MicroPower/Pascal-RT DLLOAD utility, which is described
in
the
MicroPower/Pascal-RT System User's Guide.)
Note that a down-line load may take several minutes with PASDBG.
Syntax

LOAD [/qualifier]

[dev:] name [.ext]

Command Parameters

dev
An optional host-system device name.
name
The file name.
ext
An optional file name extension.
If you do not specify an
extension, the default is
.MIM for LOAD/TARGET and .DBG for
LOAD/SYMBOL.
If you specify an extension other than .MIM or
.DBG, you must specify /TARGET, /EXIT, or /SYMBOL.
Command Qualifiers

/TARGET
Instructs PASDBG to down-line load a specified application memory
image file into the target system.
/SYMBOL
Instructs PASDBG to load the symbol table file into its memory
(necessary for symbolic debugging and for use of kernel-specific
commands) •

Version 1.5, February 1984

3-28

COMMAND REFERENCE
(no qualifier)
Instructs PASDBG to perform a LOAD/TARGET, a
LOAD/SYMBOL, or
both, depending on the file extension given (.MIM, .DBG, or none
specified, respectively).
/EXIT

~- Instructs PASDBG to down-line load a specified application memory

image file into the target system, to start the application, and
then to exit.
(Control is returned to the operating system on
the host.) This option is intended for application programs built
without debugger support.
Example
PASDBG>load procs2<RET>
;PASDBG-I-BOTWARN, Starting primary boot load, please wait •••
;PASDBG-I-BOTLD, Primary boot loaded, getting closer •••
Target stopped at physical (00001234), virtual (001534)
@#5656
Executing KERNEL code
No process set, KERNEL mapping in effect
This example down-line loads the file PROCS2.MIM into the
loads the file PROCS2.DBG into PASDBG.

Version 1.5, February 1984

3-29

JMP

target

and

COMMAND REFERENCE

3.19

LOG

The LOG command opens a log file on a host-system disk. The debugger
then writes to that file either all text appearing on the screen or
only the commands you issue.
You can use this command to create a file of frequently used commands
that you invoke with the @ command. Or you can save a copy of the
debugger dialog for analysis later.
PASDBG writes only your commands to the log file if the extension
the file is .COM. The default log file extension is .LOG.

Syntax

LOG [dev:] name [{.ext}]
.C011'

Command Parameters

dev
The name of the device that will contain the log file.
name
The log file's name.
ext
The log file's extension.

The default extension is .LOG •

• COM
The command file extension. This instructs PASDBG
the log file only the commands you issue.
Example

PASDBG>log setup.com<RET>

Version 1.5, February 1984

!build a command file

3-30

write

COMMAND REFERENCE

SET BREAK

3.20

SET BREAK

The SET BREAK command establishes a breakpoint at a specified address.
A breakpoint stops execution of your application program when the
instruction at the specified address is about to execute.
When a
breakpoint
is triggered,
PASDBG stops the application program,
notifies the user, and returns to command mode.
You can assign a message to the breakpoint.
PASDBG displays the
message when the breakpoint is triggered.
If you set the breakpoint
on a Pascal statement number and do not assign a message, PASDBG
assigns the statement number and the procedure name as the message.
If you set the breakpoint on a Pascal label and do not assign a
message,
PASDBG assigns "LABEL n procedure name" as the message (n is
the label number) • PASDBG truncates messages that are longer than 18
characters.
When you set a breakpoint in a procedure, the breakpoint triggers each
time the procedure is called, regardless of the number of calls. When
you set a breakpoint in a process, the breakpoint triggers on all
invocations of the process unless the /PROCESS switch is used to
specify a particular process.
You cannot set more than eight breakpoints and tracepoints.
Syntax
SET ~REAK[/qualifier •.• ] address-expression ['message']
Command Parameters
address-expression
An expression giving the location at which the breakpoint
be set. Address-expressions may be one of the following:
number

•

statement-number
a Pascal statement
integer) valid within the current scope.

•

LABEL label-number -- a Pascal label number (unsigned integer)
defined within the current scope, preceded by the keyword
"LABEL" and a space.

•

@(radix]address -- a physical, kernel, or virtual address
preceded by an at sign and an optional radix indicator. The
four radix
indicators are % (octal),
%0
(octal),
%X
(hexadecimal) , and %D (decimal) • The address is interpreted
as a physical address if physical mapping is set, a kernel
address if KERNEL mapping is set, or a virtual address in the
currently set process if process mapping is set.

(unsigned

message
A message to be displayed when the breakpoint is triggered.
Version 1.5, February 1984

3-31

COMMAND REFERENCE
Command Qualifiers
/AFTER: integer
~
Sets a counter on the breakpoint, causing the breakpoint to
trigger only after the application program has executed the
instruction the number of times specified by integer.
The
default count is 1. After the breakpoint is triggered, the count
is reset to 0 but the qualifier remains in effect. Thus, AFTER:2
causes the breakpoint to trigger every other time it is reached.
/PROCESS:process-id
~~Causes the breakpoint to trigger only
if the selected process
executes the instruction. The specified process must currently
exist. Process-id, which selects the process, may be one of the
following:
a

Pascal

process-descriptor

variable

•

process-descriptor
name.

•

'process-name' -- a runtime process name, enclosed in quotes.

•

serial-number -- a runtime
integer) •

•

@[radix]PCB-address -- a process control block (PCB)
address
preceded by an at sign and an optional radix indicator. The
four radix indicators are % (octal),
%0
(octal),
%X
(hexadecimal) , and %D (decimal) •

process

serial

number

(unsigned

Example
PASDBG>set scope baker<RET>

!set break on baker, label 10

PASDBG>set break LABEL 10<RET>
PASDBG>go<RET>
[Target execution resumed - type <CR> to stop target]
** BREAKPOINT #0 'LABEL 10 BAKER'
Target stopped at physical (00053070), virtual (053070)
#2,@#53304
In statement 3 + 0 in
Program ZEPHOD, Module ZEPHOD, Scope: BAKER
Process 6, (no name), PCB at KERNEL (035436)
NOTE
You cannot set breakpoints
in
the
Debugger Service Module (DSM)
or at
label $TRAP in the $TRAP kernel routine.
Setting breakpoints at these addresses
will generate either a debugger error
message,
if symbols are loaded, or
unpredictable results,
if symbols are
not loaded.

3-32

MOV

COMMAND REFERENCE

SET ODT

3.21

SET ODT

The SET ODT command forces the application program to halt and causes
all further entries to be interpreted as commands to the target
computer's Micro-ODT. PASDBG prints all target responses on the
terminal.
Video is reversed to signify that the ODT sequence is from
the target, not the host system. Type CTRL/C or CTRL/A to exit from
Micro-ODT mode.

The SET ODT command has no arguments.
Syntax
SET ODT
NOTE
Remember that SET ODT halts the target.
If
you
want
to
continue
target
execution, you must type a P command
(Micro-ODT
proceed)
before you exit
Micro-ODT with CTRL/C or CTRL/A.

Example
PASDBG>set odt<RET>
@P (CRTL/C typed here, echoed below)
"'C

Displayed in
reverse video

PASDBG>show target<RET>
Target stopped at physical (00041456), virtual (041456)
R0,-(SP)
In statement 1 + 0 in
Program PROCS2, Module PROCS2, Scope: Pl
Process 14, (no name), PCB at KERNEL (022416)
Not using memory management hardware

Version 1.5, February 1984

3-33

MOV

COMMAND REFERENCE

SET PHYSICAL

3.22

SET PHYSICAL

The SET PHYSICAL command sets the current mapping to physical
addressing.
Program and scope settings are canceled and symbolic
access is disabled. Subsequent commands must use physical addresses
in place of symbol references.
The SET PHYSICAL command has no
arguments.
Syntax

SET PHYSICAL
Example

PASDBG>set prog procs2<RET>
;PASDBG-I-NOMOD, Mo6•1le and Scope set to "PROCS2"
PASDBG>ex k<RET>
(043722} : 0

!access k symbolically

PASDBG>set physical<RET>
PASDBG>show scope<RET>
?PASDBG-E-NOSCOPE, No scope set
PASDBG>ex @%43722<RET>
(043722} : 0

!access k by physical address

3-34

COMMAND REFERENCE

SET PROCESS

3.23

The SET PROCESS command selects a process in the application program
and sets mapping
to that process.
SET PROCESS allows you to access
variables local to that process and any other information found on the
process stack.
Note that when you set process, you do not specify the lexical
name
for
the process.
Instead,
you must specify one of the identifiers
associated with the process when it
is created.
(MicroPower/Pascal
application programs can call multiple copies of a process.) These
identifiers are Pascal descriptor variables,
the name given the
process, serial numbers, or process control block addresses.
If you do not know the valid
process
identifiers,
use the SHOW
PROCESS/ALL command to display all active processes on the target.
You can then find the process that you want to set process to.
Use the SHOW PROCESS command with no arguments
to display the
currently set process.
Note
that whenever the debugger stops the
target system, process is reset to the currently running
process,
if
any.
Thus,
until you issue a SET PROCESS command, the currently set
process is the currently running process.
Note that the SET PROGRAM
program's static process.

command

implicitly

sets

process

the

You cannot use the SET PROCESS command on a process that has
been created.

not

yet

If you SET PROCESS to use SET WATCH on a local variable,
be sure to
set a breakpoint on the termination point of the process and to cancel
the
watchpoint
before
the
process
terminates.
Otherwise,
unpredictable results can occur.

Syntax
SET PROCESS process-id

Command Parameter
process-id
Selects a process.

Process-ids may be one of the following:

•

process-descriptor
name.

•

'process-name' -- a runtime process name, enclosed in quotes.

•

serial-number -- a runtime
integer) •

•

@[radix]PCB-address -- a process control block
(PCB)
address
preceded by an at sign and an optional radix indicator.
The
four
radix
indicators are % (octal),
%0
(octal),
%X
(hexadecimal), and %D (decimal).

Pascal

process-descriptor

process

3-35

serial

number

variable

{unsigned

COMMAND·REFERENCE
Example

PASDBG>show proc/all<RET>
!list all processes
Process 14, (no name) , PCB at KERNEL (0 2 2416)
Process 3, name = 'PROCS2', PCB at KERNEL (021626)
PASDBG>show proc<RET>
!list currently set process
Process 3, name = 'PROCS2', PCB at KERNEL (021626)
PASDBG>set proc 14<RET>

!now we can access 14's local vars

3-36

COMMAND REFERENCE

SET PROGRAM

3.24

SET PROGRAM

The SET PROGRAM command sets lexical scope to a specified program and
sets mapping
{PROCESS)
to the specified program's static process.
Lexical scope must be set -- with SET PROGRAM and SET SCOPE -- so that
the debugger can differentiate between multiple occurrences of a
symbol name within an application. The debugger requires that you set
lexical scope before accessing any Pascal or KERNEL symbols. If you
do not issue a SET PROGRAM command, you can access only physical
locations with PASDBG.
The MODULE option on SET PROGRAM sets lexical scope to a particular
module within the program.
The default for \MODULE is the program
(the module that contains the program declaration).
The KERNEL qualifier on SET PROGRAM sets the program to
the
MicroPower/Pascal kernel and, in a mapped system, sets KERNEL mapping.
In this mode, you can access kernel symbols and addresses.
SET PROGRAM cancels the scope set with SET SCOPE and resets scope to
the specified module or -- if no module is specified -- to the main
block of the program.
Syntax
program-name[\module-name]}
SET PROGRAM

{ KERNEL

Command Parameters
program-name
The name of a Pascal program in your application.
module-name
The name of a Pascal module in that program.
KERNEL
A keyword that sets scope (and in a mapped
the kernel.

system,

Example
PASDBG>set prog procs2<RET>
;PASDBG-I-NOMOD, Module and scope set to "PROCS2"

3-37

mapping)

COMMAND REFERENCE

SET SCOPE

3.25

SET SCOPE

The SET SCOPE command lets you establish a lexical path name that
leads to a specific symbol. The SET SCOPE path name is composed of
all the procedure, function, or process names that lead lexically to
that symbol.
SET SCOPE makes it possible to differentiate between
multiple occurrences of a symbol name within a program or module.
(See also the SET PROGRAM command.)
If the last procedure, function, or process in a lexical path has
multiple occurrences, such as with recursion, you can differentiate
between occurrences by specifying an occurrence number.
This number
is the number of occurrences before the last occurrence of the
procedure, fun ct ion, or process.
If you do not specify a n.umber,
PASDBG defaults to the last occurrence.
SET SCOPE does not reset process -- mapping is unaffected .•
Whenever the debugger stops the target system, scope is reset to the
currently running program, procedure, function, or process, if any.
Syntax
SET SCOPE proc-name[\proc-name ••• ] [:integer]

Command Parameters
proc-name
The name of a Pascal procedure, function, or process.
integer
An occurrence number.
This parameter sets scope to a particular
occurrence of the last procedure, function, or process in the
specified path name -- "integer" occurrences before the last one.
Example
[SYSTEM (MicroPower)]PROGRAM EL (INPUT,OUTPUT);
VAR PHI : REAL;
PROCEDURE TAU;
PROCEDURE EPSILON;
VAR PHI : INTEGER;
BEGIN {EPSILON}
PHI := 1;
END; {EPSILON}
BEGIN {TAU}
END; {TAU}
BEGIN {MAIN PROGRAM}
TAU;
PH I

: = 2. 0;

END. {MAIN}

3-38

COMMAND REFERENCE
In this example, two distinct variables have the name PHI.
Setting
scope to either EL or TAU\EPSILON distinguishes between the two
variables.
If PASDBG does not find the variable specified in the current scope,
it removes the last procedure, function, or process from the scope
list and then tries again. For example, assume a scope of:
PASDBG>set scope MARY\BAKER\EDDY<RET>
Also assume a user-specified variable name of:
PASDBG>EXAMINE FRED<RET>
Then PASDBG would attempt to find FRED, using the following scopes:
MARY\BAKER\EDDY
MARY\BAKER
MARY
FRED (as a global variable)
If PASDBG still cannot find the
error message:

variable,

issues

the

?PASDBG-E-SYMNDF, Symbol not defined in current scope

3-39

following

COMMAND REFERENCE

SET STEP

3.26

SET STEP

The SET STEP command establishes the default parameters for the s:TEP
command.
The parameters select the increments by which PASDBG steps
and determine whether or not STEP skips over called routines.
You can set step parameters only after
executed its first instruction.

the

application

You can set step parameters only for the currently
(SET PROCESS has no effect) •

program

has

executing

process

after

each

PDP-11

STATEMENT
Causes the execution of the program to stop after
statement. STATEMENT is the default increment.

each

Pascal

Syntax

Command Parameters
INSTRUCTION
Causes the execution of the program to
instruction.

stop

INTO
Steps the program through all subroutines,
including
OTS
routines.
If a subroutine call is executed while you are
stepping through a routine, PASDBG will stop and report on the
first instruction of the called subroutine. INTO is the default
into/over setting.
OVER
Causes the program to step over all subroutine calls.
If a
subroutine call is executed while you are stepping through a
routine, PASDBG will stop and report only after the subroutine
returns, when the next instruction or statement in the calling
routine is about to execute.
Example
PASDBG>show step<RET>
Step parameters: into statement
P~SDBG>set

step over<RET>

PASDBG>show step<RET>
Step parameters: over statement

3-40

COMMAND REFERENCE

SET TRACE
3.27

SET TRACE

The SET TRACE command establishes a tracepoint, which is functionally
equivalent to a breakpoint immediately followed by a GO.
You can SET
TRACE on physical/virtual locations, on a Pascal statement number, or
on a Pascal label. When the instruction at the specified address is
about to execute, the tracepoint triggers, and PASDBG reports the
tracepoint number and any optional message you specify. Program
execution then continues.
If you SET TRACE on a label and do not specify a message, PASDBG sets
the message to "LABEL n procedure name", where n is the label number.
If you SET TRACE on a statement and do not specify a message,
PASDBG
sets the message to "n procedure name", where n is the statement
number.
You cannot set more than eight breakpoints and tracepoints.

Syntax
SET !RACE[/qualifier ••• ] address-expression ['message']

Command Parameters
address-expression
An expression giving the location at which the tracepoint
be set. Address-expressions may be one of the following:
number

(unsigned

•

statement-number
a Pascal statement
integer) valid within the current scope.

•

LABEL label-number -- a Pascal label number (unsigned integer)
defined within the current scope, preceded by the keyword
"LABEL" and a space.

•

MACRO-global-name -- the name of a MACR0-11 global symbol
defined in the current program. Dots ( ". ") in the symbol name
must be entered as underscores (" ");
for example, PC.LNK is
entered as PC LNK.
-

•

@{radix]address -- a physical, kernel, or virtual address
preceded by an at sign and an optional radix indicator.
The
four radix
indicators are % (octal),
%0
(octal),
%X
(hexadecimal), and %0 (decimal) • The address is interpreted
as a physical address if physical mapping is set, a kernel
address if KERNEL mapping is set, or a virtual address in the
currently set process if process mapping is set.

message
A message to be displayed when the tracepoint is triggered.

Version 1.5, February 1984

3-41

COMMAND REFERENCE

Command Qualifiers
/AFTER: integer
~
Sets a counter on the tracepoint, causing the tracepoint to
trigger only after the application program has executed the
instruction the number of times specified by the integer.
/PROCESS:process-id
----Causes the tracepoint to trigger only if the selected process
executes the instruction. The specified process must currently
exist.
Process-id, which selects the process, may be one of the
following:
a

Pascal

process-descriptor

variable

•

process-descriptor
name.

•

'process-name' -- a runtime process name, enclosed in quotes.

•

serial-nmnber -- a runtime
integer) .

•

@[radix]PCB-address -- a process control block (PCB)
address
preceded by an at sign and an optional radix indicator.
The
four radix indicators are % (octal),
%0
(octal),
%X
(hexadecimal), and %D (decimal).

process

serial

number

Example
PASDBG>set trace 3 'I got here'<RET>
PASDBG>go<RET>
[Target execution resumed - type <CR> to stop target]
** TRACEPOINT #0 'I got here'
NOTE
You cannot set tracepoints
in
the
Debugger Service Module
(DSM)
or at
label $TRAP in the $TRAP kernel routine.
Setting tracepoints at these addresses
will generate either a debugger error
message,
if symbols are loaded, or
unpredictable results,
if symbols are
not loaded.

3-42

(unsigned

COMMAND REFERENCE

SET WATCH
3.28

SET WATCH

The SET WATCH command establishes a watchpoint at a location you
specify.
A watchpoint operates as a breakpoint if the contents of a
location or a Pascal variable change. The debugger stops the program
and displays both the previous and current contents of the location.
You can assign a message to the watchpoint.
If you
displays the message when the watchpoint is triggered.

do,

PASDBG

You cannot use the SET WATCH command on a Pascal structure such as an
array.
However, you can set watch on a simple variable within the
structure, such as one of the array elements.
NOTE
You cannot
numbers.

watch

labels

statement

Syntax
SET ~ATCH[/AFTER:integer] address-expression ['message']

Command Parameters
address-expression
An expression giving the location at which the watchpoint
be set. Address-expressions may be one of the following:

•

variable-name -- the name of a Pascal variable defined within
the current scope. Structure names are prohibited. However,
you can specify an array element or a record field if it is a
simple type.

•

MACRO-global-name -- the name of a MACR0-11 global symbol
defined in the current program. Dots (".") in the symbol name
must be entered as underscores("")~
for example, PC.LNK is
entered as PC LNK.
-

•

@[radix]address -- a physical, kernel, or virtual address
preceded by an at sign and an optional radix indicator. The
four radix indicators are % (octal),
%0
(octal),
%X
(hexadecimal) , and %0 (decimal). The address is interpreted
as a physical address if physical mapping is set, a kernel
address if KERNEL mapping is set, or a virtual address in the
currently set process if process mapping is set.

message
A message to be displayed when the watchpoint is triggered.

Command Qualifier
/AFTER: integer
Causes the watch to trigger only after the variable
value the specified number of times.

Version 1.5, February 1984

3-43

has

changed

COMMAND REFERENCE
Example

PASDBG>set watch k<RET>
PASDBG>go<RET>
[Target execution resumed - type <CR> to stop target]
** WATCHPOINT #0 'K'
Old contents: 0
New contents: 2
Target stopped at physical (00036744), virtual (36744)
#144, (R0)
In statement 3 + 0 in
Program PROCS2, Module PROCS2, Scope: PROCS2
Process 3, name = 'PROCS2', PCB at KERNEL (021626)

3-44

MOV

COMMAND REFERENCE

SHOW BREAK

3.29

The SHOW BREAK command lists all currently set breakpoints, along with
the following information for each breakpoint:

• The physical address of the breakpoint
• The value set with /AFTER in SET BREAK (if not set, AFTER = 1)
• The current value of the /AFTER count
The serial number of the process specified with /PROCESS in
• SET
BREAK
• The message field, if any
The SHOW BREAK command has no arguments.

Syntax
SHOW BREAK

Example
PASDBG>show break<RET>
t
Physaddr AFTER
0
00053070
1
1
00053012
5
2
00052720
1

process S.N.
(any)
(any)
(any)

TAG
'LABEL l'
'l PROCl'
'l PROC2'

Note that breakpoints #1 and #2 are set at the same
but in two different procedures.

statement

count
0
3
0

3-45

number

COMMAND REFERENCE

SHOW CALLS

3.30

SHOW CALLS

The SHOW CALLS command causes PASDBG to display a list of the chain of
routines that invoked the currently running routine. Note that this
chain is not the lexical scope of the procedures. The command has no
arguments.
Related commands are SHOW SCOPE, which displays the current lexical
scope;
SHOW TARGET, which displays the current state of the
application; SHOW RUN QUEUE, which displays the currently running
process;
SHOW PROCESS, which displays the currently set process;
SHOW PROCESS/ALL, which displays all processes in the application;
SHOW PCB, which displays process control block information; and SHOW
STRUCTURE, which displays the structure of a Pascal program, process,
or routine.
Syntax
SHOW CALLS
Example
PASDBG>show calls<RET>
in
Process 18, (no name), PCB at KERNEL (022556)
created by
Process 3, name
'GENl ', PCB at KERNEL (021~26)
In STORE MESSAGE
Called from Pl
In this example, the currently running routine, STORE MESSAGE, was
called from the process Pl, the current activation of which was
created by the process 'GENl'.

3-46

COMMAND REFERENCE
SHOW EXCEPTION

3.31

SHOW EXCEPTION

The SHOW EXCEPTION command displays the last exception message
generated by the target and sent to the host system. The SHOW
EXCEPTION command has no arguments.
Use the SHOW EXCEPTION command before resuming target execution with
the GO command;
SHOW EXCEPTION will have no effect if GO has been
issued since the last exception message was received.
syntax
SHOW EXCEPT ION
Example
PASDBG>go<RET>
[Target execution resumed - type <CR> to stop target]
RESOURCE Exception, Insufficient space for stack (ES$NMS)
in statement 3 in
physical (00036674), virtual (036674)
Program GENl, Module GEN!, Scope: SETUP
Exception reported from near
in non-Pascal code •
physical (00043434), virtual (043434)
Process 3, name = 'GENl ', PCB at KERNEL (021626)

PASDBG>show exc<RET>

!retrieve off-screen message

RESOURCE Exception, Insufficient space for stack (ES$NMS)
physical (00036674), virtual (036674)
in statement 3 in
Program GENl, Module GEN!, Scope: SETUP
Exception reported from near
physical (00043434), virtual (043434)
in non-Pascal code •
Process 3, name = 'GENl ', PCB at KERNEL (021626)

3-47

COMMAND REFERENCE

SHOW EXCEPTION GROUPS

3.32

The SHOW EXCEPTION GROUPS command displays a list of the process
groups with established exception-handling processes.
It also lists
the types of exceptions that are handled for each process group and
the packet queue that is signaled when one of the listed exceptions
occurs in one of the listed process groups.
To determine which
processes handle the exceptions, examine the packet queues listed by
SHOW EXCEPTION GROUPS with the SHOW PACKET QUEUE command.
To determine what exception-handling procedure,
if any, has
established for an individual process, use the SHOW PCB command.

been

Syntax
SHOW EXCEPTION GROUPS
Example
PASDBG>sh exc group<RET>
Exception class TRAP:
Group 12 Packet Queue :
Serial U3,
name = 'ex%%%%' Packet Queue
Group 100 Packet Queue :
name = 'ex%%%%' Packet Queue
Serial #13,
Exception class SYSTEM SERVICE:
Group 12 Packet Queue :
name = 'ex%%%%' Packet Queue
Serial #13,
Group 100 Packet Queue :
Serial #13,
name = 'ex%%%%' Packet Queue

is at KERNEL (103522)
is at KERNEL (103522)
is at KERNEL (103522}
is at KERNEL (103522)

PASDBG>sh packet queue @%103522<RET>
Serial #13,
name = 'ex%%%%' Packet Queue is at KERNEL (103522)
FIFO ordered Packet Queue has value of
0
Processes Blocked on this Queue:
Process 17, name= 'eaxch', PCB at KERNEL (104246)
FIFO ordered Packets waiting on this Queue:
none.
In this example, exception handling has been established for process
groups 12 and 100. TRAP exceptions are handled for process groups 12
and 100, as are SYSTEM SERVICE exceptions.
In this case, all TRAP and
SYSTEM SERVICE exceptions for process groups 12 and 100 are handled
through one packet queue, 'ex%%%%', and one handler process,
'eaxch'.
In a different case~ multiple packet queues and handlers might have
been established.

3-48

COMMAND REFERENCE

SHOW FREE PACKETS

3.33

SHOW FREE PACKETS

The SHOW FREE PACKETS command displays the number of packets that are
left in the kernel packet pool. You can use this command to look at
the pool and determine if you have allocated enough packets in the
configuration file.
The SHOW FREE PACKETS command has no arguments.
Free packet information is also displayed by the SHOW FREE
command.
Syntax
SHOW FREE PACKETS
Example
PASDBG>show free packets<RET>
There are 20 free packets

Version 1.5, February 1984

3-49

STRUCTURES

COMMAND REFERENCE

SHOW FREE STRUCTURES
3.34

SHOW FREE STRUCTURES

The SHOW FREE STRUCTURES command displays the amount of memory left in
the
kernel
free-memory pool
(the memory used to hold kernel
structures).
This memory pool can become fragmented
if
many
structures are created and destroyed.
You can use the command to look
at the pool and then determine if you have allocated enough memory for
the structures in the configuration file or if you have destroyed all
the structures that you have finished using.
SHOW FREE STRUCTURES
also displays the number of packets left in the kernel packet pool.
The SHOW FREE STRUCTURES command has no arguments.
Syntax

SHOW FREE [STRUCTURES]
Example

PASDBG>show free<RET>
There are 20 free packets
Free memory for KERNEL structures:
Location (21374) Size 60
Location (21720) Size 2768
Total number 2, total_rnernory 2828

3-50

COMMAND REFERENCE

SHOW INACTIVE QUEUE
SHOW INACTIVE QUEUE

3.35

The SHOW INACTIVE QUEUE command lists all processes on the inactive
queue and their process names, numbers, and process control block
(PCB) addresses. The inactive queue contains processes that have
aborted with fatal
exceptions
(that is, exceptions for which no
exception handling was established).
The SHOW INACTIVE QUEUE command has no arguments.
Syntax
SHOW INACTIVE [QUEUE]
Example
PASDBG>show inactive<RET>
Processes on the inactive queue:
Process 3, name = 'PROCS2' PCB at KERNEL (036736)
Process 9, (no name), PCB at KERNEL (035116)
NOTE
When a process is removed from the run
queue and is placed on the inactive
queue,
it is also deleted from the
system name table and the active process
list.
For this reason,
the commands
SHOW
PROCESS/ALL
and
SHOW
NAMES,
described elsewhere in this chapter,
will not list the aborted process, and a
SET PROCESS to the name of the aborted
process will not work. To use the SET
PROCESS or SHOW PROCESS commands with a
process that is on the inactive queue,
you must refer to the process by its
process control block (PCB) address.

3-51

COMMAND REFERENCE

SHOW NAMES

3.36

SHOW NAMES

The SHOW NAMES command lists all the named kernel structures, their
serial numbers, and their kernel addresses. After giving the SHOW
NAMES command, you can use commands such as SHOW PCB, SHOW SEMAPHORE,
SHOW PACKET QUEUE, and SHOW RING BUFFER to display more detailed
information about named kernel structures. The SHOW NAMES command has
no arguments.

Syntax
NAMES
-SHOW -

Example
PASDBG>show names<RET>
Serial #10, name = '$XLCTL' PCB is at KERNEL (022122)
Serial #12, name = 'XL00 ' Ring Buffer is at KERNEL (022332)
Serial #2, name= '$XLADR' PCB is at KERNEL (021512)
Serial #11, name = 'XLIO ' Ring Buffer is at KERNEL (022236)
Serial #3, name = 'GENl I PCB is at KERNEL (021626)
Serial #8, name= '$XLA ' Packet Queue is at KERNEL (022046)

3-52

COMMAND REFERENCE

SHOW PACKET QUEUE

3.37

SHOW PACKET QUEUE

The SHOW PACKET QUEUE command displays information about a packet
queue.
Use the command to display the packet queue name, address,
serial number, and value; a list of all processes waiting on the
packet queue; and a list of the packets waiting on the queue.
To display all currently valid packet queue names, use the SHOW
command.

NAMES

Syntax
SHOW PACKET QUEUE structure-id

Command Parameter
structure-id
Selects the packet queue to be displayed.
one of the following:
a

Structure-ids

queue-semaphore-descriptor
descriptor variable name.

•

'queue-semaphore-name' -enclosed in quotes.

•

@[radix]queue-semaphore-address -- the kernel address of a
queue semaphore, preceded by an at sign and an optional radix
i n d i cat o r • The four
rad ix
i n d i cat ors a re % ( o ct a 1 ) ,
%o
(octal), %X (hexadecimal), and %0 (decimal).

runtime

queue

•

Pascal

may

semaphore

name,

Example
PASDBG>show packet queue '$XLA'<RET>
Serial #6, name = '$XLA ', Packet Queue is at KERNEL (021456)
Priority ordered Packet Queue has value of 0
Processes blocked on this Queue:
Process 2, name = '$XLADR', PCB at KERNEL (021512)
Priority ordered packets waiting on this Queue:
none.

3-53

COMMAND REFERENCE

SHOW PCB

3.38

SHOW PCB

The SHOW PCB command displays information about the process control
block for the process you specified. Depending on the argument, SHOW
PCB prints information about the currently set process or a specified
process.
SHOW PCB lists the process's priority, state, status, mapping type
(general, device, driver, or privileged), exception mask, blocking
semaphore or ring buffer, suspend count, context switch options,
context switch location, stack pointer, and program counter.
You can display process control block information for a process other
than the currently set process by specifying a process identifier -- a
Pascal descriptor variable, name variable, serial number, or control
block address.
Use SHOW PROCESS/ALL to list currently valid process
identifiers.
Syntax
SHOW PCB [process-id]
Command Parameters
(no arguments)
Indicates the currently set process.
process-id
Selects a process.

Process-ids may be one of the following:
a

Pascal

process-descriptor

variable

•

process-descriptor
name.

•

'process-name' -- a runtime process name, enclosed in quotes.

•

serial-number -- a runtime
integer) •

•

process

serial

number

Examples
!list current process-ids
PASDBG>show proc/all<RET>
Process 14, (no name) , PCB at KERNEL (022416)
Process 12, (no name) , PCB at KERNEL (022272)
Process 8, name = '$XLCTL', PCB at KERNEL c021102)
Process 3, name = 'PROCS2', PCB at KERNEL (021626)
Process 2, name = '$XLADR' , PCB at KERNEL (021512)

3-54

(unsigned

COMMAND REFERENCE
PASDBG>show pcb 14<RET>
Process 14, (no name), PCB at KERNEL (022416)
Priority = 1, Status = Ready/Active, Type = General
PC = (041574), Stack pointer = (045464), PSW = (000), Suspend
count = 0
Termination address = (040260) , Exception group = 1
Exceptions accepted: none
Stack limits (045514) to (044676)
Context switch options = switch location (047706)
PASDBG>show pcb 12<RET>
Process 12, (no name) , PCB at KERNEL (0 2 2 27 2)
Priority = 174, Status = Wait/Active, Type= Driver
Process is blocked on a Ring Buffer, Address = (022172)
Name ='XL00
PC = (034014), Stack pointer = (036006), PSW = (000), Suspend
count = 0
Termination address = (034060), Exception group = 1
Exceptions accepted: none
Stack limits (036030) to (035716)
Context Switch options = none

3-55

COMMAND REFERENCE

SHOW PROCESS

3.39

SHOW PROCESS

The SHOW PROCESS command lists the name, serial number, and kernel PCB
address for a specified process. Depending on the arguments, PASDBG
provides this information on the currently set process -- which may or
may not be the currently running process -- the requested process, or
all processes.
To display a particular process, you do not specify the lexical name
for the process.
Instead, you must specify one of the identifiers
associated with the process when it is created (MicroPower/Pascal
application programs can create multiple copies of a process) • These
identifiers are Pascal descriptor variables, name variables, serial
numbers, or control block addresses.
If you do not know the valid process identifiers,
PROCESS/ALL command to display those currently valid.

use

the

SHOW

Whenever PASDBG stops the target system, process is reset to the
currently running process, if any.
Thus, until you issue a SET
PROGRAM or SET PROCESS, the currently set process is the currently
running process. However, the SHOW PROCESS command should not be used
as a substitute for SHOW RUN QUEUE, which always displays the running
process, regardless of current process setting •

.syntax
SHOW PROCESS [/ALL]

[process-id]

Command Parameters
(no arguments or qualifiers)
Requests information on the currently set process.
process~id

Specifies a process.

Process-ids may be one of the following:
a

Pascal

process-descriptor

variable

•

process-descriptor
name.

•

'process-name' -- a runtime process name, enclosed in quotes.

•

serial-number -- a runtime
integer) •

•

@[radix]PCB-address -- a process control block (PCB) address
preceded by an at sign and an optional radix indicator. The
four radix indicators are % {octal),
%0
(octal),
%X
{hexadecimal), and %D (decimal).

process

Command Qualifier
/ALL
Directs P~SDBG to display all processes.

3-56

serial

number

(unsigned

COMMAND REFERENCE
Example
PASDBG>show process/all<RET>
Process 3, Name = 'PROCS2' ,PCB at KERNEL (036272)
Process 9, (no name), PCB at KERNEL (035116)
PASDBG>show process<RET>
!currently set process
Process 9, (no name), PCB at KERNEL (035116)
PASDBG>show run<RET>
!currently running process
Process 3, name = 'PROCS2', PCB at KERNEL (036272)

3-57

COMMAND REFERENCE

SHOW READY/ACTIVE QUEUE

3. 4.0

SHOW READY/ACTIVE QUEUE

The SHOW READY/ACTIVE QUEUE command 1 ists all processes on the
ready/active queue and their process names, numbers, and process
control block (PCB)' addresses. The SHOW READY/ACTIVE QUEUE command
has no arg um en ts.

Syntax
fil!OW ~Y/ACTIVE [QUEUE]

Example
PAS.DBG>show ready/active queue<RET>
Processes on the Ready/Active queue:
Process 3, name = 'PROCS2', PCB at KERNEL (036736)
Process 9, (no name), PCB at KERNEL (035116)

3-58

COMMAND REFERENCE

SHOW READY/SUSPENDED QUEUE

3.41

SHOW READY/SUSPENDED QUEUE

The SHOW READY/SUSPENDED QUEUE command lists all processes on the
ready/suspended queue and their process names, numbers, and process
control block (PCB) addresses.
Syntax
SHOW READY/SUSPENDED [QUEUE]
Example
PASDBG>show ready/suspended queue<RET>
Processes on the Ready/Suspended queue:
Process 3, name = 'PROCS2', PCB at KERNEL (036736)
Process 9, (no name), PCB at KERNEL (035116)

3-59

COMMAND REFERENCE

SHOW RlNG BUFFER
3.42

SHOW RING BUFFER

The SHOW RING BUFFER command displays information about a ring buffer.
The command displays the ring buffer name, address, serial number,
filled bytes used, low limit, high limit, the processes waiting for
room on the ring buffer, the processes waiting to get an element from
the ring buffer, the get and put pointers and queues, and the size of
the buffer.
To display all currently valid ring buffer names, use the
command.

SHOW

NAMES

Syntax
SHOW RING [BUFFER] structure-ID
Command Parameter
structure-ID
Selects the ring buffer to be displayed.
one of the following:
a

Pascal

Structure-ids
ring

buffer

may

descriptor

•

ring-buffer-descriptor
variable name.

•

'ring-buffer-name' -- a runtime ring buffer name, enclosed
quotes.

•

@[radix]ring-buffer-address -- the kernel address of the ring
buffer,
preceded by an at sign and an optional radix
indicator. The four radix indicators are % (octal), %0
(octal), %X (hexadecimal), and %D (decimal).

Example
PASDBG>show ring rb<RET>
Serial #12, name= 'rbl
' Ring Buffer is at KERNEL (022332)
Ring Buffer has 0 bytes used out of 8
Buffer addresses KERNEL (022366) to (022376)
Location of next get = (022366), next put = (022366)
Process currently doing get:
Process 14, (no name), PCB at KERNEL (022432)
FIFO ordered Putting Processes waiting
none.
FIFO ordered Getting Processes waiting :
none.

3-60

CO"MAND REFERENCE

SHOW RUN QUEUE

3.43

SHOW RUN QUEUE

The SHOW RUN QUEUE command displays the currently running process's
number, name, and process control block (PCB) address. The SHOW RUN
QUEUE command has no arguments.
Syntax
SHOW RUN [QUEUE]
Example
PASDBG>show run queue<RET>
Process 3, name = 'PROCS2', PCB at KERNEL (036272)

3-61

COMMAND REFERENCE

SHOW SCOPE

3.44

SHOW SCOPE

The SHOW SCOPE·command displays the current lexical scope setting.
The debugger resets scope to the currently running program, process,
or routine, if any, whenever it interrupts target execution. However,
if the application has not started executing or if you have issued a
SET PROGRAM or SET SCOPE command since execution was interrupted, SHOW
SCOPE will display the lexical scope you have set. If scope is not
set, PASDBG displays the messag~ "?PASDBG-E-NOSCOPE, No scope is set".
The SHOW SCOPE command has no arguments.
Syntax
SHOW SCOPE
Example
PASDBG>show scope<RET>
Program DEMO, Module DEMO, Scope: STORE MESSAGE

3-62

COMMAND REFERENCE

SHOW SEMAPHORE

3.45

SHOW SEMAPHORE

The SHOW SEMAPHORE command displays information about a binary or
counting semaphore. The command displays the semaphore name, address,
serial number, and type; the status of the semaphore variable; and a
list of all processes waiting on the semaphore.
To display all currently valid semaphore names,
command.

use

the

SHOW

NAMES

Syntax
SHOW SEMAPHORE structure-ID
Command Parameter
structure-ID
Selects the semaphore to be displayed.
of the following:

Structure-ids may be

queue

semaphore

one

•

semaphore-descriptor -- a Pascal
variable name.

•

'semaphore-name' -- a runtime queue semaphore
in quotes.

•

@[radix]semaphore-address
the kernel address
of
the
semaphore, preceded by an at sign and an optional radix
i nd i cat o r • The f o u r rad ix i nd i ca tors a re % {o ct a 1 ) , %0
{octal), %X {hexadecimal), and %D (decimal).

name,

descriptor
enclosed

Examples
PASDBG> show semaphore 'flag'<RET>
Serial #10, name= 'flag ', Binary Semaphore is at KERNEL
(037006)

FIFO ordered Binary Semaphore is closed.
Processes blocked on this Queue:
Process 15, name= 'scan ', PCB at KERNEL (036052)
PASDBG>show semaphore 'bonzo'<RET>
Serial #11, name = 'bonzo ', Counting Semaphore is at KERNEL
(036756)

FIFO ordered Counting Semaphore has value of 0
Processes blocked on this Queue:
Process 14, name
'owha ' PCB at KERNEL (036236)
Process 13, name
'tagoo ' PCB at KERNEL (036422)
Process 17, name
'siam
PCB at KERNEL (036711)
NOTE
MicroPower/Pascal
case sensitive.
name from "flag."

structure names are
"Flag" is a different

3-63

COMMAND RE'FERENCE

SHOW STEP

3.46

SHOW STEP

The SHOW STEP command shows the current parameters for STEP.
These
parameters can be set with a SET STEP command or reset to the system
default with a CANCEL STEP or an INIT command.
(PASDBG performs an
implicit !NIT at start-up time and when it executes a LOAD command.)
See the SET STEP command for more information on the parameters.
The
SHOW STEP command has no arguments.

Syntax
§J!OW STEP

Example
PASDBG>show step<RET>
Step parameters:
instruction over

3-64

COMMAND REFERENCE

SHOW STRUCTURE

3.47

SHOW STRUCTURE

The SHOW STRUCTURE command displays the Pascal program structure of
the
variable you specify.
If the variable has a subordinate
structure, such as with a record or an array, PASDBG displays those
structures.
If you specify a process, a procedure, or a function, PASDBG displays
a list, starting with the specified element, of all processes,
procedures, functions, and variables lexically subordinate to the
element.
Syntax
SHOW STRUCTURE structure-name
Command Parameter
structure-name
Selects the structure to be displayed.
any of the following:

Structure

names

can

•

variable-name -- the name of a Pascal variable

•

routine-name

the name of a Pascal procedure or function

•

process-name

the name of a Pascal process

•

program-name

the name of a Pascal program

Examples
PASDBG>SHOW STR FOO<RET>
In this example, FOO is a record containing an integer field,
field, and a Boolean field. PASDBG displays:
FOO : RECORD OF
BAR3
BOOLEAN
BAR2
REAL
BAR!
INTEGER
Shown below is the structure of a program named GEN!.
PASDBG>show str genl<RET>
MAIN BLOCK GEN 1
INDEX : SUBRANGE 0 •• 65535
MESSAGES : ARRAY [1 •• 11] OF
: ARRAY (1 .• 16] OF
: CHAR
I : SUBRANGE 0 •• 65535
PROCEDURE STORE MESSAGE
MSG : ARRAY [l •• 16] of
: CHAR
PROCESS GEN2
NAME : ARRAY [1 •• 6] OF
: CHAR
3-65

real

COMMAND REFERE-NCE

PRIORITY : INTEGER
STACK SIZE : INTEGER
DESC 7 INTEGER
I : SUBRANGE 0 •• 65535
PROCEDURE SETUP
PROCEDURE PRINT MESSAGES
I : SUBRANGE i .. 65535

3-66

COMMAND REFERENCE

SHOW TARGET
3.48

SHOW TARGET

The SHOW TARGET command gives information on the state of the hardware
and software active on the application system.
SHOW TARGET indicates
the location at which the target is currently stopped,
the assembler
instruction at that location, the process name and serial number, and
whether or not memory management hardware is in use.
The SHOW TARGET command has no arguments.
Syntax

-SHOW -TARGET
Example
PASDBG>show target<RE~>
Target stopped at physical (00036562), virtual (036562)
4 (SP)
In statement 1 + 0 in
Program PROCSl, Module PROCSl, Scope: Pl
Process 14, (no name), PCB at KERNEL (022416)
Not using memory management hardware

3-67

CLR

COMMAND REFERENCE

SHOW TRACE

3.49

SHOW TRACE

The SHOW TRACE command lists 'all currently set tracepoints, along with
the following information for each tra:eepoint:

• The physical address of the tracepoint
• The value set with /AFTER in SET TRACE (if not set, AFTER = 1)
• The current value of the /AFTER count
serial number of the process specified with /PROCESS
• The
SET TRACE

• The message field, if any
The SHOW TRACE command has no arguments.
Syntax
SHOW !_RACE
Example
PASDBG>show trace<RET>
#
Physaddr AFTER
0
00053~70
1
1
00053012
5
2
00052720
l

count
0
3
0

3-68

process S.N.
(any)
(any)
(any)

TAG
'LABEL l '
'l PROCl'
'Marker'

COMMAND REFERENCE

SHOW WATCH
3.50

SHOW WATCH

The SHOW WATCH command lists
currently set watchpoints:

the

following

information

about

all

•

The physical address of the watchpoint

The value set with /AFTER in SET WATCH (if not set, AFTER

•

The current value of the /AFTER count

•

The message field, if any

The SHOW WATCH command has no arguments.
Syntax
SHOW WATCH
Example
PASDBG>show watch<RET>
Physaddr AFTER
#
0
00053070
1
~0053012
1
5
2
CHHJ52720
1
3,4
00052760
1

count
0
3
0

process S.N.
(any)
(any)
(any)
(any)

TAG
'Marker'
'Proc l'
'Proc 2'
'a real'

The "process S.N." column in the example above has no meaning for
watchpoints.
It is significant only for breakpoint and tracepoint
display (see the SHOW BREAK and SHOW TRACE commands}.
Note that real numbers use two watchpoints.

3-69

COMMAND REFERENCE

SPAWN

3.b

SPAWN

The SPAWN command is implemented only in the RSX and VMS versions of
PASDBG.
This command permits you to issue any single-line RSX or VMS
command while in PASDBG and then return to the debugging session.
The
command allows you to use an editor, for example, from within PASDBG.
To use SPAWN under PASDBG-VMS, you must have the TMPMBX
(temporary
mailbox)
privilege.
Also,
SPAWN creates a subprocess,
so your
subprocess quota has to be large enough to allow creation of the
additional process.
If your quota is not sufficient, PASDBG prints
the error message "?PASDBG-E-NODCL, Unable to Spawn subprocess".

Syntax
SPAWN cmd

Command Parameter
cmd
A single-line RSX or VMS (DCL) command.

Version 1.5, February 1984

3-70

COMMAND REFERENCE

3.51

STEP

The STEP command allows you to execute the application program one
increment at a time, as defined by SET STEP. When the application
system finishes performing the step, PASDBG issues information as if a
breakpoint had occurred.
You can also specify stepping through
multiple increments with an integer qualifier.
The /INSTRUCTION, /STATEMENT, /INTO, and /OVER qualifiers override the
default parameters specified with SET STEP.
The default parameters
are restored after the STEP command has executed.
Use the STEP command only within a process.
If you execute a STEP and
another process begins execution, the program proceeds until the first
process begins executing again.
The exception to this rule occurs if watchpoints are set in your
application. Because both WATCH and STEP use the same trap mechanism,
the watchpoints cause you to step into the new process.
If another debugger command interrupts a STEP -- a breakpoint
called routine, for example -- the STEP command is canceled.

Syntax
~TEP [/qualifier [/qualifier]]

[ integerl

Command Parameter

integer
The number of step increments
application execution.

perform

before

stopping

Command Qualifiers

/INSTRUCTION
Causes the program to stop after one PDP-11 instruction.
/STATEMENT
-- Causes the program to stop after one Pascal statement.
/INTO
--- Steps the program into any subroutine call, including an OTS
routine call.
If the instruction or statement about to execute
calls a subroutine, PASDBG will stop and report on the first
instruction of the called subroutine.
If no subroutine is
called, /INTO has no effect.
/OVER
Causes the program to step over any subroutine call, stopping
only when the subroutine returns and the next instruction or
statement in the currently active routine is about to execute.
If no subroutine is called, /OVER has no effect.

version 1.5, February 1984

3-7,0.1

COMMAND REFERENCE
Example
PASDBG>show step<RET> !currently at stmt 2+0 in STORE MESSAGE
Step parameters: into statement
PASDBG>s/instr<RET>
Target stopped at physical {00036740), virtual {036740)
In statement 2 + 4 in
Program GENl, Module GEN!, Scope: STORE MESSAGE
Process 18, {no name), PCB at KERNEL {022556)
PASDBG>s<RET>

ASL R3

!return to statement increments

Target stopped at physical {00036776), virtual {036776)
PC,41166
In statement 3 + 0 in
Program GENl, Module GENl, Scope: STORE MESSAGE
Process 18, {no name), PCB at KERNEL {022556)

3-71

JSR

APPENDIX
TARGET INTERFACE SPECIFICATIONS

The MicroPower/Pascal
debugger,
PASDBG,
runs
on
an
RT-11,
RSX-llM/M-PLUS, or VAX/VMS system, hereafter referred to as the host
system, which is totally
distinct
from
the
system
running
MicroPower/Pascal
and
the user application programs, hereafter
referred to as the target system. The two systems communicate with a
high baud rate, asynchronous, serial line (RS-232).
The debugger
service module (DSM) -- a part of the MicroPower/Pascal executive with
addressing access to the entire target system address space -- is
responsible for controlling the target's part
of
the
serial
communication.
The DSM, under commands from the debugger over the
serial link, examines and modifies target memory, sets and reports
breakpoints, tracepoints, and watchpoints, and adjusts memory mapping
so that the debugger can reference virtual addresses within processes
and target kernel data.
(Other tasks the DSM performs are listed
below.)
The communication scheme developed to handle messages between the
debugger and the target DSM is an ASCII-character-oriented scheme
subject to the following protocols.

A.l

PROTOCOLS

Two basic protocols control the host
to
target
link:
the
inquiry/response protocol and the asynchronous message protocol.
These protocols are described below.

A.1.1

Inquiry/Response Protocol

The debugger initiates the inquiry/response protocol as a request for
data or a command for action by the DSM. Messages in this protocol
can be passed only while the DSM is in the "idle" state, that is,
after stopping for break or watchpoints or after a HALT.
The HALT
command itself is the exception to this rule.
Individual message formats differ according to function, but all
the same basic format.
The script is as follows:

have

Debugger:
{born} {message} cc {eom}
DSM:
{born} {response} cc {eom}
In the example, {born} is the "beginning of message" character, and cc
is a
2-character hexadecimal checksum derived by adding the ASCII
characters in the message and
inverting the result.
The checksum
value does not include the {born} character, itself, or the { eom} "end
of message" character.
Version 1.5, February 1984

A-1

TARGET INTERFACE SPECIFICATIONS

On a checksum error (host to target), the receiving end sends a "<" or
a
">" (target to host), and the sender sends the message back in the
same format.
The messages "<" and ">" are known as "NACK"
(negative
acknowledgment).
NACKs do not have checksums, because it is better
for a sender to send again rather than to NACK a NACK.
The message receiver is also responsible for detecting the case where
This
too much time has elapsed while waiting to receive a character.
is a "timeout," which causes the receiver to send a
NACK to the
sender, causing the sender to send its message again.

A.1.2

Asynchronous Message Protocol

The asynchronous message protocol, initiated by the DSM only while the
target is running,
is a report that some event(s) the debugger is
waiting for has occurred.
Examples of this type of event include the
occurrence of a breakpoint, a watchpoint, and a target exception.
The
DSM will stop after sending an asynchronous message but can send more
than one
(multiple breaks at the same address, one instruction that
changes more than one w0tchpoint, and so on).
For this reason,
there
is a handshaking protoco~ while the DSM transmits the break, watch, or
stop messages.
This handshaking sequence is as follows:
DSM:
DBG:

"&" (or ">" to request a resend of above message)

DBG:

"&" (or ">")

DSM:
DBG:

" &"

{born} {message} cc {eom}
{born} {message} cc {eom}
{born} H cc {eom}

(indicate DSM now idle)

If an asynchronous message receives no response within a
timeout
period,
the DSM will continue to send the asynchronous message until
it is acknowledged.
Note that the use of the 2-digit hex
inverted
checksum, as well as the receiver timeout checking on both ends, is
identical to the inquiry/response case.
The "ACKs"
("&")
are sent
alone, without {born}, checksum, or { eom} -- just 1 ike "NACKs".
NOTE

Currently,
{eom}
host-to-target messages
(ASCII
CTRL/Z)
for
messages;
{born} = "!"

A.2
A.2.1

"/"
for
and octal 32
target-to-host

MESSAGES
Inquiry/Response Messages

The following are the currently defined
inquiry/response messages.
Note that the {born} character, the checksum characters, and the {eom}
character have been removed.
All numeric information is passed in ASCII hexadecimal (Radix 16).

Version 1.5, February 1984

A-2

TARGET INTERFACE SPECIFICATIONS
Clear Break
DBG: 9n
DSM: 1
n = breakpoint ordinal

(0-7)

Clear Watch
DBG: Bn
DSM: 1
n = watchpoint ordinal (table entry)
Fetch from KERNEL
DBG: Ckkkk
DSM: ldddd
or
{memory access error}
kkkk = Kernel address for fetch
Data from fetch
dddd
Fetch Register (current mapped process)
DBG: Et
DSM: ldddd
t
register number 0-7 (or 8=PSW) for fetch
d = register contents from fetch
Fetch via Physical Address
DBG: 0ppppoo
DSM: ldddd
or
0

{memory access error}

ppppoo = physical address for fetch
pppp = PAR value which is high 13 bits of address
oo = 6-bit offset in block
dddd = result of fetch
Fetch via Virtual Address
DBG: 4vvvv
DSM: ldddd
or
0

vvvv
dddd

{memory access error}
virtual address for fetch
data from fetch

GO
DBG: 6
DSM: 1

A-3

TARGET INTERFACE SPECIFICATIONS
Interrogate PC
DBG: 2
DSM: lvvvvppppookkkk
vvvv = virtual PC at STOP
pppp = par value of phys PC (high 16 bits)
oo = low 6 bits of physical PC
kkkk
KERNEL PCB address of running process ($RUN)
Restart (restore to "just loaded" state)
DBG: K
DSM: 1
Return mapping flag
DBG: 7
DSM: 1

{target using memory management hardware}

or
0

{target using physical address mapping only}

Set Break
DBG: 8nppppoo
DSM: 1
or
0

{memory access error}

n = breakpoint ordinal (table entry) 0-7
pppp = par value of phys addr (high 16 bits)
oo = low 6 bits of physical address
Set Mapping by Process ID
DBG: 3kkkk
DSM: 1
kkkk = kernel address of PCB for process
Set Watch
DBG: Anppppoo
DSM: 1
or

{memory access error}

n = watchpoint ordinal (table entry)
pppp = par value of phys addr (high 16 bits)
oo = low 6 bits of physical address
Step (report every instruction in this process)
DBG: I
DSM: 1
Step (report on next RTS PC)
DBG: J
DSM: 1

A-4

TARGET INTERFACE SPECIFICATIONS
STOP
DBG: *
DSM: {asynchronous sequence}
Note that the stop message (•••) is not sent via the
normal message protocol; only a single "*" is sent.
After the debugger requests a stop, the DSM and
the debugger enter the asynchronous handshaking
sequence (the asynchronous protocol described
above) • The conclusion of the sequence -- the reception
of the final •{born} H cc {eom}" message -- indicates
to the debugger that the target is now idle.
Store Register
DBG: Ftdddd
DSM: 1
t =register number for store (0-5,8; No SP, PC)
d = data for store
Store to KERNEL
DBG: Dkkkkdddd
DSM: 1
or

{memory access error}

kkkk
KERNEL addr for store
dddd = data for store
Store via Physical Address
DBG: lddddppppoo
DSM: 1
or

{memory access error}

ppppoo = physical address for fetch.
pppp = PAR value which is high 13 bits of address
oo = 6-bit offset in block
dddd = data for store
Store via Virtual Address
DBG: Svvvvdddd
DSM: 1
or
0

{memory access error}

vvvv
dddd

= data for store

virtual address for store

Translate kernel to physical
DBG: Hkkkk
DSM: lppppoo
kkkk = kernel address to be translated
pppp = par value of phys addr (high 16 bits)
oo = low 6 bits of physical address
A-5

TARGET INTERFACE SPECIFICATIONS
Translate virtual to physical
DBG: · Gvvvv
DSM: lppppoo
vvvv = virtual address to be converted
pppp = par value of phys addr (high 16 bits)
oo = low 6 bits of physical address

A.2.2

Asynchronous Messages

The following formats are for the asynchronous messages -- those
messages, coming from the target, that are not a direct response to an
inquiry by the host debugger. Note that asynchronous messages will
not be sent between a host inquiry and the DSM response.
Abort (exception detected in exception handler)
DSM: A
DBG: &

{no eom, cc, or born}

DSM: Bn
DBG: &

{no eom, cc, or born}

Break

n = breakpoint ordinal
DSM init (power-up sequence executed via load or !NIT/RESTART)
DSM: In
DBG: &

{no eom, cc, or born}

n = DSM version number
Exception
DSM: E
DBG: &

{no eom, cc, or born}

Kernel abort (kernel detects fatal trap in kernel)
DSM: K
DBG: &

{no eom, cc, or born}

Step (step report)
DSM:
DBG:

s
&

{no eom, cc, or born}

DSM: Wn
DBG: &

·{no eom, cc, or born}

Watch

n = tracepoint ordinal

A-6

INDEX

Abbreviations, command and
qualifier, 3-1
Aborted process, 2-12, 3-51
Addressing, kernel, physical, or
virtual, 2-2, 2-3, 2-5, 3-4,
3-9, 3-11, 3-17, 3-19, 3-31,
3-41, 3-43
Application program name, 1-11
At (@) symbol
address prefix, 3-4, 3-9, 3-11,
3-17, 3-19, 3-31, 3-35, 3-41,
3-43, 3-53, 3-54, 3-56, 3-60,
3-63
indirect command file, 2-9,
3-2, 3-30
Micro-ODT prompt, 2-17, 3-2,
3-33

Binary semaphore, 2-10, 3-63
Bootstrap for LOAD command, 1-5
Breakpoint, 2-5, 3-4, 3-31, 3-45
••• BRK slave task, 1-5
Build procedure
application program, 1-8
PROCS2 example program, 1-16

CANCEL BREAK command, 2-5, 3-4
CANCEL PROCESS command, 2-2, 3-6
CANCEL SCOPE command, 2-2, 3-7
CANCEL STEP command, 2-5, 3-8
CANCEL TRACE command, 2-5, 3-9
CANCEL WATCH command, 2-5, 3-11
Chapter summary, vii
CLOSE command, 2-9, 3-13
Command
abbreviations, 3-1
examples. See Chapter 3
operators, 3-1
summary, 1-13
syntax, 1-13.
See also Chapter
3

types, 2-1
Command files, 2-9, 3-2, 3-30
Commands
data display and modification,
2-8
debugging aids, 2-9, 2-13
Version 1.5, February 1984

exception-handling display,
2-13
general debugging, 2-1
loading the application, 2-1
program execution control, 2-5
real-time debugging, 2-10
state queue display, 2-12
symbol and address resolution,
2-2
typed kernel structure display,
2-10.1
Communication, host/target, 1-1,
1-3, 1-4, 1-5, 1-6, 2-13,
2-17, 3-2, 3-33, A-1
Communications protocol,
PASDBG-DSM, A-1
Configuration file, l-1, 1-7,
1-8, 1-16
Configuration, host and target,
1-3
Conventions, document, viii,
1-16, 3-1
Counting semaphore, 2-10, 3-63
Critical section errors, 2-14
CTRL/A Micro-CDT command, 2-18,
3-33
CTRL/C command, 2-10, 3-14
CTRL/O command, 2-10, 3-15
CTRL/Y command, 2-10, 3-16

Data display and modification
commands, 2-8
Data juxtaposition errors, 2-16
DBG file, 1-4, l-8, 1-11, 1-12,
2-2, 3-28
Deadlock errors, 2-16
Debugger command format, 1-13
Debugger invocation, 1-12, 1-17
Debugger service module, l-1,
1-6, 1-8, 3-32, 3-42, A-1
Debugging aids, 2-9, 2-13
Debugging session termination,
1-13
DEPOSIT command, 2-B, 3-16.1
Document conventions, viii, 1-16,
3-1
DSM.
See Debugger service module
DSM-PASDBG communications
protocol, A-1

Index-1

INDEX

Lexical scope, 2-2, 2-3, 3-37,
3-38
LOAD command, 1-4, 1-5, 2-1, 3-28
Local variables, 2-17, 3-19, 3-35
LOG command, 2-9, 3-30
Log file generation, 2-9, 3-30

Errors
critical section, 2-14
hints for debugging, 2-14
race condition, 2-16
real-time, 2-14
EXAMINE command, 2-8, 3-19
Exception
codes, 2-18
groups, 2-13, 3-48
handling, 2-13, 2-18, 3-48
Exceptions, fatal, 2-18
Execution control commands, 2-5
Execution error restart, 1-2
EXIT command, 2-9, 3-16, 3-22

MACR0-11 global symbols, 3-4,
3-9, 3-11, 3-17, 3-19, 3-30,
3-41, 3-43
MACR0-11 processes, debugging,
1-10, 1-11

FALCON.
See SBC-11/21
FALCON-PLUS.
See SBC-11/21
Fatal exception, 2-18

General debugging commands, 2-1
Global MACR0-11 symbols, 3-4,
3-9, 3-11, 3-17, 3-19, 3-31,
3-41, 3-43
GO command, 2-5, 3-23

HALT command, 2-9, 3-24
Hardware required by PASDBG, 1-3
HELP command, 2-10, 3-25
Host and target configuration,
1-3
Host/target communication, 1-1,
1-3, 1-4, 1-5, 1.-6, 2-13,
2-17, 3-2, 3-33, A-1

Inactive queue, 2-12, 3-51
Incremental execution, see STEP
Indirect command files, 2-9, 3-2,
3-30
INIT command, 2-5, 3-26
Insufficient processing time
error, 2-16
Invocation, PASDBG, 1-12, 1-17

Kernel, access to, 1-4, 1-8, 2-2,
2-3, 2-10, 2-11, 2-12, 3-4,
3-9, 3-11, 3-17, 3-19, 3-28,
3-31, 3-37, 3-41, 3-43
Keyword abbreviations, 3-1
Keywords, 1-13
KXTll-C/arbiter transactions,
debugging, 2-19
KXTll-C XL handler prefix file,
1-9
Version 1.5, February 1984

Macro-ODT mode, 2-19
Mapping, 2-3, 2-5, 3-4, 3-6, 3-9,
3-11, 3-17, 3-19, 3-31, 3-34,
3-35, 3-37, 3-38, 3-41, 3-43
Micro-ODT mode, 2-13, 2-17, 3-2,
3-33
MIM file, 1-4, 1-5, 1-6, 1-11,
1-12, 2-2, 3-28
Modules, program, 1-2, 1-10, 2-3,
3-37
MPBLD build procedure, 1-8, 1-9
MPB UI LD bu i 1 d pro c ed u r e , 1- 8 , 1- 9
MPPBRK slave task, 1-4, 1-5
MPSETUP command file, 1-12

Name, application program, 1-11

0 OT mode , 2-1 3 , 2-1 7 , 3-2 , 3 - 3 3
On-line help, 2-10, 3-25
Operator symbols, 3-1

Packet queue, 2-10, 3-53
PASDBG-DSM communications
protocol, A-1
PASDBG invocation, 1-12, 1-17
PCB.
See Process control block
Physical memory, access to, 2-2,
2-3, 2-5, 3-4, 3-6, 3-9,
3-11, 3-17, 3-19, 3-31, 3-34,
3-37, 3-41, 3-43
Process, aborted, 2-12, 3-51
Process control block, 2-10, 3-54
Process control variables and
structures, 1-2, 2-10
Process groups, 2-13, 3-48
Process setting, 2-2, 2-3, 2-5,
3-6, 3-34, 3-35, 3-37, 3-56
PROCS2 example program
build, 1-16
listing, 1-1 7
Program name, 1-11
Program setting, 2-2, 2-3, 2-4,
2-5, 3-6, 3-34, 3-35, 3-37,
3-62

Index-2

INDEX

Qualifier abbreviations, 3-1
Queue
inactive, 2-12, 3-51
packet, 2-10, 3-53
ready/active, 2-12, 3-58
ready/suspended, 2-12, 3-59
run , 2 -12 , 3 -61
Queue semaphore, 2-10, 3-53

Race conditions, 2-16
Read-only-memory (ROM)
restriction, 1-4
Ready/active queue, 2-12, 3-58
Ready/suspended queue, 2-12, 3-59
Real-time debugging commands,

2-rn
Real-time errors, 2-14
Required hardware and software,
1-2
Ring buffer, 2-10, 3-60
RSXll-M/M-PLUS host system, 1-3,
1-4, 1-5, 1-6, 1-7, 1-9,
1-12, 1-17
RT-11 host system, 1-3, 1-4, 1-5,
1-6, 1-7, 1-8, 1-12
$RUN, kernel variable, 2-14
Running PASBDG, 1-1, 1-6, 1-12,
1-17
Run queue, 2-12, 3-61

SBC-11/21, 1-7, 1-9, 2-19
Scope example, 2-4, 3-38
Scope setting, 2-2, 2-3, 2-4,
2-5, 3-6, 3-7, 3-34, 3-37,
3-38, 3-62
Semaphore, 2-10
binary, 3-63
counting, 3-63
queue, 3-53
SET BREAK command, 2-5, 2-17,
3-31
SET ODT command, 2-13, 3-33
SET PHYSICAL command, 2-2, 3-34
SET PROCESS command, 2-2, 2-17,
3-35
SET PROGRAM command, 2-2, 2-17,
3-37
SET SCOPE command, 1-17, 2-2,
2-17, 3-38
SET STEP command, 2-5, 3-40
SET TRACE command, 2-5, 3-41
SET WATCH command, 2-5, 3-43
with FALCON, 2-19
with local variables, 2-17,
3-35
warning, 2-16
SHOW BREAK command, 2-5, 3-45
SHOW CALLS command, 2-5, 3-46
SHOW EXCEPTION command, 2-13,
3-47
Version 1.5, February 1984

SHOW EXCEPTION GROUPS command,
2-13, 3-48
SHOW FREE PACKETS command, 2-10,
3-49
SHOW FREE STRUCTURES command,
2-10, 3-50
SHOW INACTIVE QUEUE command,
2-12, 3-51
SHOW NAMES command, 2-10, 3-52
SHOW PACKET QUEUE command, 2-10,
3-53
SHOW PCB command, 2-10, 3-54
SHOW PROCESS command, 2-2, 3-56
SHOW READY/ACTIVE QUEUE command,
2-12, 3-SA
SHOW READY/SUSPENDED QUEUE
command, 2-12, 3-59
SHOW RING BUFFER command, 2-10,
3-60
SHOW RUN QUEUE command, 2-12,
3-61
SHOW SCOPE command, 2-2, 3-62
SHOW SEMAPHORE command, 2-10,
3-63
SHOW STEP command, 2-5, 3-64
SHOW STRUCTURE command, 2-8, 3-65
SHOW TARGET command, 2-13, 3-67
SHOW TRACE command, 2-5, 3-68
SHOW WATCH command, 2-5, 3-69
Software required by PASDBG, 1-4
SPAWN command, 2-10, 3-70
Statement number, 1-17, 3-4, 3-9,
3-19, 3-31, 3-41
State queue display commands,
2-12
State queue, 2-12
inactive, 3-51
ready/active, 3-58
ready/suspended, 3-59
run, 3-61
Static components of uninvoked
process, 2-17
STEP command, 2-5, 3-70.1
with FALCON, 2-19
warning, 2-16
Symbols
kernel, 1-4, 1-8, 2-2, 2-3,
3-28, 3-37
keyword, 1-13
MACR0-11 global, 3-4, 3-9,
3-11, 3-17, 3-19, 3-31, 3-41,
3-43
module, 1-2, 1-4, 1-10, 2-3,
2-4, 3-28, 3-37, 3-38
operator, 3-1

Target and host configuration,
1-3
Target/host communication, 1-1,
1-3, 1-4, 1-5, 1-6, 2-13,
2-17, 3-2, 3-33, A-1
Index-3

INDEX

T-bit, 2-14, 2-19
TDBOTM and TDBOTU bootstraps,
1-4, 1-5
TD handler, 1-4, 1-5, 1-6, 1-7
TD logical device, 1-5, 1-7, 1-17
$TRAP routine warning, 3-32, 3-42
Tracepoint, 2-5, 3-9, 3-41, 3-68
Typed kernel structures, 2-10.l

Uninvoked process, examining,
2-17, 3-19
Unprotected protection control
error, 2-16
uODT mode, 2-13,
2-1 7, 3-2,
3-33

version 1.5, February 1984

VAX-11/VMS host system, 1-3, 1-4,
1-5, 1-6, 1-7, 1-9, 1-12,1-17
Virtual addressing, 2-2, 2-3,
2-5, 3-4, 3-9, 3-11, 3-17,
3-19, 3-31, 3-41, 3-43
Watchpoint, 2-5, 3-11, 3-35,
3-43, 3-69
WATCH
with FALCON, 2-19
warning, 2-16
XL handler, 1-9, 1-16
prefix file for debugging, 1-9,
1-16

Index-4

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AA-M393B-TC

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