HP 9835A Owner's manual

HEWLETT-PACKARD

HEWLETT ~ PACKARD
Warranty Statement
Hewlett-Packard products are warranted against defects in materials and
workmanship. For Hewlett-Packard Desktop Computer Division products
sold in the U.S.A. and Canada, this warranty applies for ninety (90) days
from date of delivery.* Hewlett-Packard will, at its option, repair or replace
equipment which proves to be defective during the warranty period. This
warranty includes labor, parts, and surface travel costs, if any. Equipment
returned to Hewlett-Packard for repair must be shipped freight prepaid.
Repairs necessitated by misuse of the equipment,
or by hardware,
software, or interfacing not provided by Hewlett-Packard are not covered
by this warranty.
NO OTHER WARRANTY IS EXPRESSED OR IMPLIED, INCLUDING, BUT
NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE. HEWLETT-PACKARD
SHALL NOT
BE LIABLE FOR CONSEQUENTIAL DAMAGES.
*For other countries, contact your local Sales and Service Office to
determine warranty terms.

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Assembly Development ROM
HP 9835A Desktop Computer
Hewlett-Packard Desktop Computer Division
3404 East Harmony Road, Fort Collins, Colorado 80525
. (For World-wide Sales and Service Offices see back of manual.)
Copyright by Hewlett-Packard Company 1979

ii
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System 35 Manual Reference
The following block diagram shows manuals that are included in the System 35 Documentation
scheme and suggested progression. Dotted-line borders indicate those manuals are available
with specific options; solid
borders indicate those manuals that are shipped with every System
35.
~-
r-- --,
I Mass Storage I
Techniques Manual
L-JI-J
,----,
I Mass Storage I
LeriPhera~a.:.a~
Beginner's Guide
Reference Guide
r
I
----
I/O
Programming
Owner's
Manual
~ 7
.JV
VOperating
¢ and
--,
I
Programming Manual
----
r ,
I Assembly I
tanguage Ma:l:J
Preview
<=>
System Test
Manual
----
r Plotter ,
I Programming I
L_ Manual_J
_l!
I --,
I Interface Manuals I
L~JI_J
r------,
IPeripheral Manuals I
L ____ J
iii

iv
Chapter Summaries
Chapter 1. General Information. An introduction to the product and the manual. The pur-
pose and differences of the two Assembly Language ROMs are explained. ROM installation
procedures are given. A glossary is provided, along with a discussion of the syntactical forms
used in the manual.
Chapter 2. Getting Started. A general discussion of the assembly language system. A format
for
the creation of an assembly language program is presented. Topics such as modules,
routines,
and memory allocation are discussed, along with methods of using them effectively.
Also discussed
is the storage and retrieval of modules on mass storage.
Chapter 3. The Processor and the Operating System. Necessary information on the struc-
ture of the processor and the operating system is presented. Topics covered are: machine
architecture,
memory organization, data structures and arithmetic, and the machine instruc-
tions.
Chapter 4. Assembly Language Fundamentals. The basic statements and syntaxes used
throughout the assembly language are discussed. Program entry, assembling, symbolic opera-
tions, module creation, program and variable storage, and utilities are the topics covered.
Chapter 5. Arithmetic. Arithmetic operations are reviewed and the arithmetic utilities are
discussed. Floating point and BCD arithmetic are explained.
Chapter 6. Communicating between Basic and Assembly Language. The techniques used
to pass information to and from the assembly language programs are discussed. Calling assem-
bly routines and passing parameters are presented, along with issues involved with using
common. Applicable utilities are also discussed.
Chapter 7. I/O Handling. The various techniques of handling the receiving and sending of
information
to peripheral devices is presented. Topics are: a review of I/O-type machine
instructions, registers, applicable utilities, interrupts and interrupt service routines,
handshake-type of I/O, direct memory access, and mass storage devices.
Chapter 8. Debugging. Techniques for isolating and correcting logic problems in assembly
programs are discussed. Included in the discussion are techniques for stepping through prog-
rams, getting
dumps, patching, and using the keyboard.
Chapter 9. Errors and Error Processing. A discussion of Assembly Language ROM and
other related errors, and what causes them. Included are methods for trapping errors and
possible methods for correcting them.

v
Table of Contents
Chapter 1: General Information
Structure of the Manual. , .............................. , .............. , ........... 2
Purpose of
the ROMs . . .. ... .... . ............. ,' .... ,' ... ."., .............. 2
ROM Installation .. , .............................................................. 3
Buzzwords
........ , . . . .. , .... " .. " ...... , ........ ,. ..,.,', ..... " .. ,', ... ,., .. 4
Fundamental Syntax
.... , . . . . . .. . .. , ............... , .......... , .... , ... , .... , .... 6
Chapter 2: Getting Started
Developing Routines for Later Use ............. , .................... , .......... , ... 7
Overview . . . . . . . . . . . . . . . . .
............ , ....................... , . . . . . . . . . . . . . . . . 9
Program
Creation. . . . . . . . . . . . . . . . . . . . . .. ... ... . ............. , .............. 9
Program Entry
.......... .......... . .. , ..... , ........ , .. , .................. 14
Other Extensions .... , ...... ,., ...... , ...................................... 16
Modules, Routines, and Such .......... ............ ., ...... , ..... ,..... . ..... 17
Names ..... , , . , ....... , .............. , ..... , ............... , ........ , . . . . . .. 17
Survey of Modules
and Routines .. , .............. , . , . , ........ , ... , ........... 18
Setting Aside Memory .. ,. ....................... ...... .................... 19
Retrieving
and Storing Modules ...................... , ...... , .................... 22
Chapter 3: The Processor and the Operating System
Machine Architecture ........................... , .......... , ..................... 25
Registers .. , .. , .......... , ....... , ........................................... 26
General Memory Organization . , . , .................................. '. . . . . . . . . . 28
Protected Memory . , ............... , ... , .................. ,................. 28
Base and Current Page .......... , ........................ , ................... 29
Data Structures ......................................... , . . . . . . . . . . . . . . . . . . . . . .. 30
Integers ........... , ................... , ......... 0 • • • • • • • • • • • • • • • • • • • • • • • • • • • 30
Strings ....... , ...... , .. , , . . . .. . .. " ...... , ... "." .. " ... , .. ' ... , ... ,.,.... 30
Full-Precision Numbers ... , . , ....... , , ... , .. , .. , ................ , ........ , , .. 31
Short-Precision Numbers. .
.. .., .. ,.",., ...... , .... " ..... ,., ......... , .. ,. 31
Machine Instructions
.... ,., .... , ... , ... , ......... , ........................... ,.. 32
Operands ......... ,., .. , .... , ..... ' ...... ,., ....... , ... " .... " .. " .. " .. 32
Indirect Addressing ........... , , . , .. , . , .. , ... , .. , ... , .. , ................. , . . . 34
Load/Store Group .. , . , .... , .... , ..... , .. , . , ... , , , , .... , ..... , .. , . , .... , , , . , 34
Integer Math Group ........ , , .. , , ..... , ... , ........... , ..... , ................ 35
Branch Group .. , .. , ........ , .. , ................. , ........... , .... , ..... , .... 36
Test/Branch Group ... , .... , ... " .. , ..... , ..... " .......................... ,37

vi
Test/ Alter /Branch Group < < < < < < •• , , • < < , •••• , < ••••• < < •••••••• < ••••• , •••••••• 38
Shift/ Rotate Group < ••••• < < ••••••• , • • ••••••••••••••• <. • ••••••• < •• < •• < • " • 40
Logical Group· ......... < •• < < ••••••••• , •••••• , , •• < •• < •••••••• , •••• < < ••••••••• 41
Stack
Group ..................... . .... < • •• < •••• < ••••• < ••••• < ••••••••••••• 42
BCD Math Group· .......................... , ............ < •••••••• , •••••• , •• < 44
I/O Group ................................ < • < < < ••••• < •••••••• < < < ••••••• ···47
Miscellaneous . , , ....... < •• , , , • , • , • , < < , , < •••• < < , •••••• , • , , ••••••• , ••••••••••• 48
Chapter 4: Assembly Language Fundamentals
Program Entry , .. , ., ., ..... < • , , •••••••• , •••••• , •••••••• , < < ••••• , •••••••• < •• , • < • 49
Assembly Language Source ............. '. " ....................... < •••• < ••• 51
Actions· ... , ................... < ••••••• , •••••• < , •••••••• < ••••••••• , ••••• 51
Labels
.... < < < • , < ••••• , , ••• < •• < ••• , , • • • • • •• • ••• < • , ••••• , ••••••••• , •••••• 51
Comments'
.... , . , . . . . . . . . .. . ... , ... , .... , ... , ...... , < •••••••• < ••••••••• 53
Syntaxing the Source , .. < •• < ••••••• , •••••• < •••••••••••••••••••••••••• < ••••••• 53
Creating Modules .. < •••••• < < < < ••••••• , ••••••• < • < •• , ••••• , ••••• < •• , • , ••••• , ••••• 55
Storage .. < • < , ••••••• < ••••••• < • < < < ••• , , • < •••••••• < •••••••••••••••••••••••• < ••••• 56
Modules ...... < < ••••••••• < < •••••• < •••••••••••••••• , • < ••••• , , •••• , ••• < ••••••• 56
Variables ... , ........ , ................... < ••••••••• '.' • < < • , ••••••••••• , •• < •• 56
Data Generators· ... , < •••• , , • , •••••••• < , •• < , •••• , •••• , •• < < •••••••••••••• , •• , • 57
Repeating Instructions . , . < < • • • • • •• • ••••••• < < • < , •••••• < •• , • •• • < • , •••••••••• , •••• 59
Assembling, ........ , ... , , .. < ••••••• , , •••••• ,. ·······,····,········,··,········60
Effect of BASIC Environments < ••••••••• , •••••••••••••••• , , •••••• , , •• , ••• < • < •• 60
Source Listing Control , .................. , ... , .......... , .. , .... ", ...... < < , • 61
Page
Format· .. < < • • • • • • • , , • , ••••• , • , •••• , ,.,." < , • , ••••• , , , •••••• < •••• 62
Page Length
... , . < < •• < •••• , , • < , •••• < •••• , ••••• < • • • • • •• • •• , •••••••••••••• 63
End-of-Page Control ., < , •• , • •• ' •••• < < •••••••• < ••••••• , • , ••••• , •••••• , .' 63
Page Headings ....... , , ..... , ........ , , . < < , ••••• < < , •••• , , • < < ••••••• , •••• 64
Blank Line Generation .. < ••• , ••••••••••• , , , • < ••••• < < •••••• , < < •••••••• , • , • 65
Non-Listable Pseudo-Instructions
., ..... , .. ",............. ., ..... , ...... 65
Conditional Assembly, ......... , . , .. < < ••••• , •••••••••• , ••••••• , • , ••••• , •••••• 65
Relocation ..... , .. , < •••••••• , •••••• , • , •••••••••••••••• , , , ••••••• < , •• < ••• , ••• 68
Symbolic Operations ,.,.' ................ , .................. , ..... ,., ... < < • • • •• 69
Pre-Defined Symbols .,., ..... , .......... " ...... < < ••• , •••• , •••• , •• , •• , •••••• 69
Defining Your Own .. , . , .. , . < ••••••••••• , ••••• , •••••••• < • • • • • • • •• " •• , •• , •• 71
Literals
.', ... , ............ , ......... < , , • < < ••••• , < ••• , • , < •••••••••••••• , ••••• 72
Evaluation of
Literals, .... , .... , .... , ... , .. < < , • < , ••••• , •• , ••• < < ••••••••••• 72
Nesting Literals ,
......... < ••••••••••• < < •••• < , < ••••••• < •••••••• , , , •••••• < • 73
Nonsensical Uses of Literals· <
•••••••••••••••• < •• < •• , • , •• < •••• , •• , , ••• , • , •• 74
Literal Pools .......... , ... < < •••• , •• < < < •••••••••••••• , ••••••••• , , •••• , •••• 74

vii
Expressions . , . , . , , ... , , ..... , . , . , , . . .. ." ....... , ...... " ....... ,', ....... , 75
External Symbols
and Elements' . , ... , . , , ....... , , , , , ..... , .... , ... , ........ , , 77
Other Absolute Elements' , , . .. . ... ,", .... ,.. .,.., .. , , . , , ... , , . . . . . .. ,., 78
Utilities' ........... . .
.............. " ........ , ....... , .... , .... , ............. 79
Chapter 5: Arithmetic
Binary Coded Decimal ....... , ........ , ......... ' ........ , ............... "., .. 83
Arithmetic Machine Instructions , ..... , .......... " .. " ........ , .. , ......... , ..... 84
BCD Registers· . , .. , , . , , . , ........... , ... ,." .............. ' , ... "' ......... , 84
BCD Arithmetic ... . . . . . . . . . .. ..... . .. , ... , ................ , .. , ... ,., ..... ,. 84
Addition , ..... , ......... ,.... , .... , , . , . . . . . . . . . .. . .... , ................ ,. 85
Ten's Complement for BCD, , ........ , ... , . , , .. , . , .... , ...... , ..... , . , ...... ·86
Floating Point Summations ' . , .... , , ........ , ............. ,.. , ...... " ...... 88
Normalization , ............. , .... , ........ , ........ , ., ,.. .., ...... ,. ··,·89
Rounding ..... ,. .... " .. , .. " ........ ,.. .".. ., ...... , .. " .. '.... ..... 89
Floating Point Multiplication ...... , ......... , .............. ,.,. . ........... 90
Floating Point Division ., ...... , , ... , ... , ....... , , ..... , ......... , .... ,., ... 92
The FDV Instruction ' ., .... . ........ , ..... , ., .. , .. , ........ , .. ,"', .. ,. 94
Thirteen-Digit Dividends' .. . ... , .... , ..... ···,········,·,··············95
Floating-Point Division Example' .... , ... .. . . . . . . . . . . . .. ····,,·····,···96
Arithmetic Utilities' , . , ......... , ...... , , .. ' .. " .. , .... " .. " ...... , ..... ,...... 99
Utility: ReI-math ., .. ,.... ,·······:···············,·······,········,······,99
Utility: Rel-to-int .......... , . " .. ".,., .................................. 102
Utility: Rel-to-sho ' , ........ , .. ' . . . . . . . . . . ., ., ...... " ..... ,.,.,' ... , ... 103
Utility: Int-to-rel .. , .... , ... , ..... , ......... ,.. ." .. " ........... , ..... 104
Utility: Sho-to-rel .'" ... , . , ... , ., ......... , .. "., .... , ....... , ........ ,. 105
Chapter 6: Communication Between BASIC and Assembly Language
The ICALL Statement .. , . . .. , ................ , .. , .......... , ....... , ......... 107
Corresponding Assembly Language Statements ........ , ... , .............. " .. 108
Arguments· ...... , ............. , ' .............. , .... ,. ..,., ..... ".. . ... 109
"Blind" Parameters ................ . .. ,........... . .... , ....... , ...... , . 112
Getting Information
on Arguments ........... " .. ,., ...... , .... , ... , ....... ,. 113
Utility:
Get-info ............... .......... ........... . .... , ........ ,. 114
Retrieving the Value of an Argument ...... ., ...... ,..... . .. , ........ ,. . .. 116
Utility: Get-value ......... ,., ...... , ..... , ............... , ... , ... , .. , .. 117
Utility:
Get-element· . , ' , ..... , , ........ , , .... , , , , .. , . .. , .... ,., ....... 118
Utility: Get-bytes .... , ......... ,., ., .. ,··.··.····,,·················,119
Utility: Get-elem-bytes .. , , . ' , ..... , , ....... , , , ... , ...... , , , .... , ...... 120

viii
Changing the Value of an Argument 0 < < , , " •• 0 0 0 0 •••• , • , , ••••••••••••••••••• , • 122
Utility:
Put-value ... , . 0 • , , ••••••••• , • , ••••• < • < •• , , , • < •• , , < •••• , ••••• < • , 122
Utility:
Put-element, ... , ... , , < •••••• , ••• , , •••••••••••••••••••••• , • , < •• , 123
Utility:
Put-bytes ........ , . , ..... , . , .. < < ••••••• , •••••• , •••••••••••••••• 124
Utility: Put-elem-bytes .... , ...... , , ................................. ", 125
Using Common ........ < •••••• , • •• • ••••• ,', ••• ,.,.", •••••••• , •••••• ,." ••••••• 127
Busy bits
............ , ... , ... " ..... ,., ........ ,. o. • ••••••••••••••••• ,'" •• 130
Utility: Busy. , . . . . . . . . . . .. . ..... , , ......... < • , •••••••••••••• , , • , , •• , , • 131
Chapter 7: I/O Handling
Peripheral-Processor Communication. , , ..... , .. < ••••••••• 0 •••••••••••••••••••••• 133
Interfaces ....... , ........ , , ............ , ... , . , .......................... , . , 134
Registers ., .. " .. , ......... , ....... ', ....... , ........... " .. , ... ,' ......... 134
Select Codes ....... < •• , •• , , ••••• , •• , ••••••••••••••• , •• ,' ••••••• , ••••• , ••• , 134
Status and Control Registers ....... , ....... , .......................... " .... 136
Status and Flag Lines, .... , , .. , ... , " ..... , ......... , .. , .... , ........... , .... 137
Programmed
I/O ...... , , .... " .' ... , .. , ..... , ........................ , ... , .. , 138
Interrupt I/O ... , , .. < • , ••••••• , ,." ••••••••• , •• " •• < < •••••••••• , , • , •• , • " •••• 138
Priorities
.. , ......... < ••••••••••••••••••• , • , ••••••••••••••••••••••••••••• , •• 140
Interrupt Service Routines and Linkage ... < ••••••• , •••••• , •••• , , ••• , ••• ,., ••• 140
Access .... , .. , . ,< ' ••••••• , •••••• , •• ,. < • , ••••••• , •••••••••• , ••••••••• , ••••• 141
Utility:
Isr-access . , .. , ........ , .......... , .... , . , ...... , ............... 143
State Preservation and Restoration ............. , ... , ......... 0 •••••••• ,. ..,. 145
Indirect Addressing in ISRs ,
.................... , .................... , .... , ., 146
Direct Memory Access (DMA) ., .... , .... , .. , .. < • , ••••••••••••••••••••••••••••••• 147
DMA Registers ,.... . ............... ' ................... , ....... " ........ 148
DMA Transfers. , .... , , ...... , ...................... , . . . . .. . ............... 149
BASIC Branching on Interrupts .... " ..... " ........... , .... , .. , .. " ... , ........ 150
ON INT Statement .. , ........................ , . , ..... < , ••••••••••••••••••••• 150
Signalling, .. " .... , ...... , ..... < < , , , ••••• , ••• , • , • , ••••••••••• , , •••••• ,. • ••• 151
Additional Pre-Defined
Symbols, 0 , ••••• , , ••••••••••••••••••• , ••••••••••••••• 153
Prioritizing ON INT Branches ........ , , .. < •••••••• , ••• , ••••••• , ••• , •••••••••• 153
Environmental Considerations
..... , , .... , ....... , .... , ...... , ............... 155
Disabling ON INT Branching ., ....... , .............. ' ............ , ... , ...... 156
Mass Storage Activities . , ...................... , ........................ , ....... 156
Reading from Mass Storage ., .......... , ............... , ..... , ... ,. < • , •••••• 157
Utility: Mm-read-start ...... <. • .••••.....•• , •••••••••••••••••••• " ..• , 158
Utility: Mm-read-xfer .. , ............ , ......... , .... , ......... ,., ..... 159

Writing to Mass Storage" ....... " , > ••• > .. > , , , •• , ." , ••• ,. > ...... , , . , . > • 160
Utility: Mm-write-start .. , ........ ". > •••••••• >. , , . . . .. > ... > > .. , . , .... 161
Utility:
Mm-write-test ... , . , . > ...... > •••••••• , •• > , , •• , , ••• , > , ••• , • , , •• > 161
System File Information .......... , .. , , ......... , ' ....... > , •• ,. > •••••• , , ••• 163
Utility: Get-file-info ....... , ............ > ••• >. , . , , . .. . .......... > ••••• 164
Utility: Put-file-info ... , ... , ...... > •••• > .......... > • , , >. >. , ..... > ••••• 165
Printing ................. ,.,....... > •• ,.,..... • > ... >>. , . . . . . . .. . ... , ... , 166
Utility: Printer_select ,.,", ..... "......... . ... , , .. , ..... >. > ......... 166
Utility: Print_string ... ,., ... , ... " ..... , >>> ••••••••••• > • , , •••••••••••••• 167
Chapter 8: Debugging
Stepping Through Programs
• > ••• , ••• " •••••• "",.,170
Individual Instruction Execution .......... , ..... " ......... >. , ..... ,. ,>,.,., 170
Setting Break Points .................. , ......... , . > ••• , • • • •• • > •••• , • • •• • •• 174
Simple Pausing ...... , >> ... , . , ...... > • , •••••••••• , •••••••••••• , ••• , • , ••• 174
Transfers ..... , ....................... > ••••••••••••• , ••••••• > .... , ..... 175
Environments .................. > •••••••••••••••••••••• , • , •••••••••••• , , 176
Data Locations ... ,' .. , ........ >> ..... , .. , , .............. , .......... , .. 177
IBREAK Everywhere ............... , , ............... , ................ >>> 178
Number of Break Points ....... >> ••••• , • • •• • •••• >. . . . . . . . .. ......... .. 179
Clearing Break Points ................. >> • • • • • • • •• ..:' • >. , , . , ..... >> .... 179
Interrogating Processor Bits ....... - ...... , .. , , . > • , •••••••• , •••••••••• >. , .. 180
Protected Memory ........ , . , . . . . . . . . . . . . . . . .. . ........ , ............... ,. 180
Dumps .. > ..... > ... , ...................... , ................ , .......... " ..... 181
Value Checking
........... >> ......... , ..... , .. , ...... , , ................ ' ..... <. 183
Functions, ............ , ... , ........................ > • • • • • • • • • • •• < • > .... , , 184
DECIMAL ......... , . . . . . .. . ............. ", < , •••••••••••• < , •• , •••••• < 184
OCTAL. < > .... < •••• , ••••••••••••• ,., ••••••• > •••• >.... . .... > ... " ... ,184
IADR .. , .. , .. , ........... < •••••••••••••••• < ••• , •• , •••••••• < •••••••• > ••• 185
IMEM ............. < •••••• , ••••••• < ••••••••••••• < •••••••••• < , ••••••••••• 186
Patching ......... , ................ > ••• > ..... , ...... > •••• > , ••••••• ' •••••••• , • 187
Chapter 9: Errors and Error Processing
Types of Errors> > ........ , ..... , ........... , .... , .......... >. . •• ,. >. -, .. , ...... 189
Syntax-Time and Assembly-Time Errors ................ , , .. , . , > ••••••• , •••••• 189
Run-Time Errors .. , .......... " >>> ••••••• , •• , ••• , ••••••••• , , , • • • • • • • • •• '" 190
Utility: Error_exit ........... > •••• , • • • • • ••••• > ................ ,.' .... 191
Run-Time Messages
...................... , ........ < •••••• , •••••••••••••••• , _ •• 193
Assembly-Time Messagefi ............ > ... , .. > ••• >> ... , ...... < ••••• >> ....... , .. > < 195
ix

x
Appendix A: ASCII Character Set
ASCII Character Codes 204
Appendix B: Machine Instructions
Detailed List 207
Bit Patterns and Timings, , , , . , . , .. , , > , > ••• , > ... > > ••• > > >, .. > ,> ••• > .. , ... > •• > , , • , 221
Alphabetic List. , .... , ....... > ••• > ••••• , ••• , ,. ,>. > •• >> >. > .. >, >. , , .. " ..... 221
Approximate Numerical List> ..... , ... , , . . . .., > • , •• > ••••• , •••• , ••••• > •••••• 221
Appendix C: Pseudo-Instructions ..... > > •
223
Appendix D: Assembly Language BASIC Language Extensions Formal Syntax: , ..... 225
Appendix E: Pre-Defined Assembler Symbols
231
Appendix F: Utilities. >> .......... , ..... >> >
233
Appendix G: Writing Utilities> ...... .
235
Appendix H: 110 Sample Programs
Handshake String Output ................. , ......................... , ......... , , 237
Handshake String Input >, >, , , , , .... >. > ••••• > ••••••• , • >. , ,. , .. > ••• > •••• >, •• ,' > 239
Interrupt String Output .... > >. , .. >, .... > •••• > ••••••••• > , •• , • , ••••••••••• < • • •• •• 241
Interrupt String Input ...... > ..... > ................. , .... , .. , ... "., .. , .. ,." .. , 244
DMA String Output " .. ,. > •• , • , • , • , ••• , ••••• " •• , •• ", •• ", ••••• , •• ",... • ••• 247
DMA String Input. , .... , .......... , ..... , .. , , , ..... , ... , . , .... , . , .. , , .... , > •••• 250
HP-IB Outputl Input Drivers. ,. ..',. . ... ", ... ,.'" ...
253
Real-Time-Clock Example .. , . " .......... , ..... " ...... > ••• , , •••
257
Appendix I: Demonstration Cartridge
Using the tape .' ... > •• , •••• , • , ••• , , , •• , • , •• , , • , ••• , • , •• , •• , • , • , •••• , ••••••• , >, . 261
Typing Aids ....... ,." ........ , .. ,. > , > ...... , .. > •••••••••• >, .... , > , •• , ••••• , 261
Appendix J: Error Messages ... > •••• , , , • " , •••
265
Mass Storage ROM Errors 269
Plotter ROM Errors 269
~"'~'~~90~~~9~"'~<"~~< >.~< "'~9"9~.9"O.'~~,,"."."9~~~99 ••
Assembly Language ROM Errors
Assembly Time Errors
Appendix K: Maintenance
270
271
Maintenance Agreements .. , .... , ... , , .. , , . , ......... , > ••• , , ••••• , ••••• , ••• , •••• 273
Sales & Service Offices
274
Subject Index 277

General Information
Chapter 1
Table of Contents
Structure of the Manual .. " ...................... ............... . ....... , ...... 2
Purpose of the ROMs ........... ,. . ..... ,........ . ...... , ....................... 2
ROM Installation .. ,........................................ .... . ............... 3
Buzzwords . . . . . . . . . . . . . . . . . . . . . . . . . .
.. , .......... , ........ " .... ,., ... ' .... , .... 4
Fundamental Syntax. , ............ , . . . . . . . . . .. . ... ,... .., .... , .............. " .. 6

Chapter 1
General Information
Welcome to the world of assembly language programming on the 9835A/B.
It is the design of the Assembly Development Read Only Memory (ROM) to help extend the
capabilities of your
9835A/ B by giving you greater control and speed through the use of
machine instructions, pseudo-instructions,
and extensions to the BASIC language.
The assembly language system
is provided to you as ROMs which plug into the drawers
provided for that
purpose in the 9835A/B. There are three physical ROMs, comprising two
"logical" ROMs -
• The Assembly Development ROM. Two physical ROMs. This ROM is always provided
with
an Execution ROM (together comprising HP product number 98339A), and the three
ROMs as a unit constitute the assembly language system of the 9835A/ B.
• The Assembly Execution ROM, HP product number 98338A. One physical ROM. Since
this ROM
is an integral part of the assembly language system, the use of the capabilities in
this
ROM is incorporated into the discussions in this manual. Information on this ROM can
be found separately in the Assembly Execution ROM manual (HP part number 09835-
90082).
It is assumed throughout this manual that you are familiar with the basic operation and lan-
guage of
the 9835A/B. It is also assumed that you are reasonably well-acquainted with at least
one other assembly language.
1

2 General Information
Structure of the Manual
It is the intent of this manual that you should be able to find between its covers everything you
need to know to use the assembly language effectively. However, since assembly language
programming
isa complex topic, the manual relies a great deal on your past experience. Most
of
the information is in succinct presentations ofa particular topic; it is not the intent to "teach"
assembly language programming to someone not familiar with the topic.
The major topics covered are: assembly language program creation (Chapter 2), the processor
and relevant operating system constructs (Chapter3), assembly language fundamentals (Chap-
ter 4), arithmetic
(Chapter 5), communications with BASIC (Chapter 6), I/O handling (Chap-
ter 7), debugging tools (Chapter 8), errors
and error processing (Chapter 9). Each topic, or
chapter, has a summary at the beginning detailing the information to be presented therein. A
compilation of
these summaries can be found immediately preceding the Table of Contents.
The manual
is organized so that each topic can be covered completely within a given chapter.
This
approach was chosen over the strict syntactical or semantical treatment of the individual
statements
and instructions. As a consequence, you may find this difficult to use as a "quick
reference" for syntax and meaning of the individual commands.
To
meet your needs for "quick reference" material, an Assembly Language System QUick
Reference Manual (HP
part number 09835-90081) is provided. In addition, you will find much
of the information in this manual
condensed and tabulated in the various appendices of this
manual.
A
recommended method for using the manuals is to start with this one as your basic learning
tool. Then you should
be able to use the QUick Reference Manual effectively for all future
reference.
Purpose of the ROMs
The Development ROM is used to write and debug assembly language programs on the
9835A/ B. The Execution ROM, provides the capability to load, run, and store assembled
routines
and modules.
The Execution ROM
can be used independently of the Development ROM. However, the
Development ROM
cannot be used without the Execution ROM. The latter's capabilities, there-
fore, are considered in this manual as
an inherent part of the Development ROM. Because of
the overhead required by the debugging features provided by the Development ROM, pro-
grams run more rapidly
if the Execution ROM is used without the Development ROM.

General Information 3
ROM Installation
Before assembly language programming can proceed, the ROMs must be in place. The installa-
tion
is a simple process.
There are several ROM drawers for the computer:
one on the right side of the machine and
four in front. Each front drawer holds up to four ROMs; the side drawer holds up to fourteen.
ROMs may be placed in any ROM slot in any drawer.
Assembly Language System ROMs
To add the ROMs, turn off the computer and remove a ROM drawer (by pulling outwards on it
until it
is completely separated from the computer). Insert the ROMs, one at a time, following
this procedure: you should orient the
ROM so that its label reads the same way as the othersin
the drawer (with the
bottom of the lettering toward the "front" of the drawer). Then insert it
vertically in
one of the unused slots. Make sure that it slides in all the way to the bottom of the
connector. There are small raised ribs on both sides of each ROM which will fit into recesses in
the slot;
if the ribs don't fit, you have not oriented the ROM correctly.
After inserting both ROMs, re-insert
the drawer in the machine (by pushing on it until it is flush
with the outside cover of
the machine). With this done, you are now ready to begin writing
assembly language programs.
Figure 1. Installing the Development ROM

4 General Information
Buzzwords
During the course of the discussions in this manual, words and phrases are used which are in
common circulation among those who are familiar with assembly languages. While the mean-
ing of most are either well-known, or are deducible from the context, there are a few which may
be unfamiliar, or unique to the 9835A/ B assembly language, or are variable from one assem-
bly
language to the next and thus need to be defined for this one. They are-
assembled location -a reference to a location in memory which may be specified in one
of the following forms -
{symbol} [
~ {numeric expression} ]
{expression} [ " {numeric expression} ]
where:
{symbol} is
an assembly location. It may be either a label for a particular machine instruc-
tion (in which case
the address of the associated instruction is used), or an assembler-
defined symbol (in which
case the associated absolute address is used), or a symbol
defined
by an EQU instruction (described in the "Symbolic Operations" of Chapter 4).
{expression}
may be a numeric expression or a string expression. If numeric, a decimal
calculation
is performed and the result is interpreted as an octal value; if the result is not
an octal representation or an integer, an error results. If a string expression is used, the
string must
be interpretable as either an octal integer constant or a known assembly
symbol (see {symbol} above).
{numeric expression} serves as a decimal offset from the given label
or constant.
byte -a group of 8 binary digits (bits).
busy bits - each variable located in the BASIC value or common areas has associated
with it two bits: a
"read" busy bit, and a "write" busy bit. When a busy bit is set, all
attempts
to perform the associated function on that variable are locked out. When a busy
bit
is cleared, the function may be performed on the variable.
conditional assembly - an aSSignation that certain portions of a module are not to be
assembled unless a condition has been set. The portions begin with any of the IFA through
IFH, and IFP, pseudo-instructions, and end with the next XIF pseudo-instruction. IFA
uses the A-condition as a test, and so on. The conditions are set by the statement assem-
bling
the module (lASSEMBLE).

General Information 5
interrupt service routine (ISH) - an assembly language routine intended to perform a
certain action, or
set of actions, when the computer receives a request from an external
device. An
"active" ISH is one which is currently enabled for a given device.
mass storage unit specifier (msus) - a single word corresponding to the BASIC lan-
guage mass storage unit specifier as described in either
the 9835A/ B Operating and
Programming Manual - HP part number 09835-90000 - or the Mass Storage
Techniques Manual- HP part number 09835-90070. An msus has the following struc-
ture -
Unit HPIB Device Select
Number Address Type1 Code
I I I I I I I I I I I I
I I L I J I I I I I I I
15 14 13 12 11 10 9 8 7 6 5 4 3 2
OBit
An msus can designate the current default as its mass storage device (meaning it will use
the device indicated by the last MASS STORAGE
IS statement executed). This is desig-
nated by having the msus be all ones (Le., equal to -1).
object module - a section of assembled code stored in the pa~ticular region of memory
set aside for
it. Though the source module for the object code may no longer be resident in
memory, when created, the module was delimited by certain pseudo-instructions
(NAM
and END) and is referenced by the name given to it by the NAM pseudo-instruction.
octal expression - a numeric expression which, when displayed or printed, appears as
an octal (base-8) number. Within arithmetic operations, it has a decimal value (base-l0).
Thus, the value 178 will appear as 17 (representing the value 1510), but if arithmetic was
performed
on it, it would act as if it were 1710. All octal expressions are necessarily
integers in the range of 0 to 1777778.
source module - a section of assembly language source code beginning with a NAM
pseudo-instruction and ending with the END pseudo-instruction.
word -two bytes; a group of 16 binary digits (bits).
1 The device type is the ASCII code for the type minus 1008.

6 General Information
Fundamental Syntax
The syntax conventions used in this manual are those used in the Operating and Programming
Manual for the
9835A/ B -
All syntax items displayed in dot matrix form should be pro-
grammed as shown.
[] Items contained in brackets are optional items.
Ellipses
mean that the previous item may be repeated
indefinitely.
In addition, the following
convention is employed throughout the Assembly Language series of
manuals -
{} Items
contained in braces are syntax items considered as a
unit. The
names inside are usually descriptive of the function
intended for that item. Whenever an item enclosed in braces
appears in the text, the notation refers to the same notation
within
an earlier syntax.

Getting Started
Chapter 2
Table of Contents
Developing Routines for Later Use < , • , , •• < •• • ••• '., < •••• , •• , ••• , < •• , , ••• , •• , , ••••• 7
Overview <
•• , , ••••••••••••••• < • • • • • • • • • • • • • • • • • • • • • • • • • • • •• • ••••••• ,. ,..... " 9
Program Creation ............................................................. 9
Program Entry ............. .. .... .. ............... ..,....... . ......... 14
Other Extensions .. < ••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 16
Modules, Routines, and Such ..... . ............ < ••• < < • < • •• ., •••• < < • , ••••• < • < • < • 17
Names. . . . . . . .. . .......... " ................. " ........... ,...... . ........ 17
Survey of Modules and Routines . . .. . < •• < ••• " •••• • < • , ••• , ••• , < , ••••••• , ••• 18
Setting Aside Memory .. , ........ , ..... < • , •••••••••••• , ••• < ••••••• < ••• < • , • < ••• 19
Retrieving and Storing Modules .,................ . .... , ....... , ...... ,'. .., .... 22