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Commodore 128
Reference Guide
for Progrommers
David L. Heiserman
Howard W. Sams & Co.
A Division of Macmillan, lnc.
4300 West 62nd Street, lndianapolis, IN 46268 USA
© 1986 by David L. Heiserman
FIRST EDITION
FIRST PRINTING-1986
All rights reserved. No part of this hook shall be reproduced, stored in a
retrievalsystem, or transmitted by any means, electronic, mechanica!,
photocopying, recording, or otherwise, without written permission from the
publisher. No patent liability is assumed with respect to the use of the
information contained herein. While every precaution has been taken in the
preparation of this hook, the publisher and author assume no responsibility
for errors or omissions. Neither is any liability assumed for damages
resulting from the use of the information contained herein.
International Standard Book Number: 0-672-22479-8
Library of Congress Catalog Card Number: 86-60936
Acquisitions Editor: Greg Michael
Editor: Katherine Stuart Ewing
Designer: T. R. Emrick
Illustrators: Don Clemons and Ralph E. Lund
Cover Artist: Gregg Butler
Compositor: Shepard Foorman Communications, Indianapolis
Printed in the United Statesof America
Trademark Acknowledgments
All terms mentioned in this book that are known to be trademarks or service
marks are listed below. In addition, terms suspectedof being trademarks or
service marks have been appropriately capitalized. Howard W. Sams & Co.
cannot attest to the accuracy of this information. U se of a term in this
book should not be regarcled as affecting the validity of any trademark or
service mark.
CP/Mis aregistered trademark of Digital Research, Inc.
Amiga, Commodore 64, and Commodore 128 are registered
trademarks of Commodore Electronics, Limited.
Contents
Preface ix
1 General Operating Procedures 1
The Three Main Operating Modes 2
Getting Familiar with the Keyboard 8
Quote-Mode Operations 16
Essential Disk Operations 17
2 BASIC Operations and Programming Procedures 23
Numeric and String Constants for BASIC 24
Numeric and String Variables in BASIC 28
Operators for Commodore BASIC 34
BASIC 7.0 Commands, Statements, and Functions 43
Keyboard Abbreviations of BASIC Operations 92
Dealing with BASIC Error Conditions 96
Tokenized BASIC Formats 106
3 DOS Operating and Programming Procedures 111
Preliminary Considerations 112
DOS-Related Commands, Functions, and Statements 113
DOS-Related Error Conditions 115
The Disk Directory 119
Disk Pormatting Procedures 121
Procedures for Saving Programs on Disk 125
Procedures for Loading Programs from Disk 132
Procedures for Copying Disk Files 138
Procedures for Cleaning Up Disks 140
Using the TEST/DEMO DISKETTE and DOS Shell 143
Sequentia! Text Files 144
Relative File Procedures 150
Direct-Access Disk Procedures 152
4 Monitor and Assembly Language Procedures 161
T~e Monitor's Hexadecimal Format 162
Essential Monitor Operations 163
The Monitor' s Machine-Language Aids 170
vi Contents
Summary of 8502 Op Codes 175
The 8502 Instruction Set 180
5 Introduetion to CP/M Procedures 201
Bringing Up CP/M on the Commodore 128 202
Help for Beginners 202
Summary of CP/M Commands 206
Makinga Backup Copy of the CP/M Disk 212
6 Text Screen Procedures 215
Preliminary Considerations 216
Switching Column Formats 220
Switching Character Sets 224
Setting the Normal/Inverse Character Format 229
Setting Screen and Character Colors 231
Using Cursor Control Features 241
Setting Alternative Text Windows 243
Using the Screen-Editing Features 250
Printing Text from Machine Language Programs 255
Working with the Character Sets 264
Working Directly with Screen Data 272
Using Alternative Screen RAM Locations 276
Writing Directly to the 80-Column Screen 279
7 Bit-Mapped Graphics Procedures 283
Bit-Mapped Screen Formats 284
Plotting Figures on the Graphics Sereens 290
Rescaling the Screen 300
Saving and Reloading Bit-Mapped Shapes 301
Setting Graphics Sereens from Machine Language Routines 304
Working Directly with Standard Bit-Mapped Sereens 307
Working Directly with the Multicolor Bit-Map Screen 314
8 Sprite Animation Procedures 317
Creating Sprite Figures 318
Saving and Reloading Sprites 322
Specifying, Positioning, a:qd Moving Sprites 323
Detecting Sprite Collisions' 329
Sprites and Machine Language Routines 337
J
9
Sound and Music Procedures 347
Preliminary Considerations 348
i
Using BASIC'sVOL and SOUND Staterne ts 351
U sing BASIC' s PLAY and TEMPO Staterne ts 356
Using the ENVELOPE Statement 360
U sing the FILTER Statement 362
Contents vii
Working Directly with the SID Registers 363
Working with Sound Enhancement Registers 369
Summary of SID Registers 372
10 Keyboard Procedures 377
Keyboard Scanning Operations 378
Working with the Non-Scanned Keys 382
Using the Keyboard Queue and GETIN 382
Using the Main Keyboard Buffer 388
U sing the Function Keys 389
11 joystick, Paddle, Light Pen, and Mouse
Procedures 394
Joystick Procedures 394
Game Paddle Procedures 398
12 Printer and Communications Procedures 401
Printer Procedures 402
Using the RS-232-C Communications Feature 406
13 Commodore 128 Memory Maps 415
The Lower RAM Addresses: $0000-$03FF 416
The Upper RAM-Only Area: $0400-$3FFF 437
BASIC ROM: $4000-$AFFF 443
Screen Editor ROM: $COOO-$CFFF 453
I/0, ROM, and RAM Block: $DOOO-$DFFF 456
Kernal ROM: $EOOO-$FFFF 475
14 Memory Management Procedures 507
The Standard Bank Configurations 508
Bank-Switching Statements, Registers, and Procedures 515
Using the BANK 1 Contiguration 521
Summary of MMU Configuration Registers 525
Bank Switching Procedures 526
A Number-System Base Conversions 531
Hexadecimal-to-Decimal Conversions 532
Decimal-to-Hexadecimal Conversions 533
Conventional Decimal to Two-Byte Decimal Format 534
Two-Byte Decimal to Conventional Decimal Format 535
Binary-to-Decimal Conversion 536
Binary-to-Hexadecimal Conversion 537
Hexadecimal-to-Binary Conversion 538
Decimal-to-Binary Conversion 538
A Complete Conversion Table for Decimal 0-255 538
viii Contents
B Derived Trigonometrie Functions 544
Index 545
Preface
Like the Commodore 128 Computer, this hook can mean a lot of dif
ferent things to different people. And like the Commodore 128, this
hook is assembied so that it can be used by a variety of users who
possess a wide range of skills and computer know-how.
• Beginners with no previous programming experience can bene
fit immediately from the elemental topics presented in the first
two chapters--how to operate the computer and how to write
programs in BASIC.
• Readers already familiar with other personal computers and BA
SIC can note in the first two chapters the differences and move
quickly to special applications topics in the remaining chapters.
• Readers who have already mastered BASIC and 6502 machine
language programming from other sourees can note the en
hancements builtinto the new version of DOS (Chapter 3) and
the machine-language monitor (Chapter 4).
• Readers who have the desire to use CP/M in a Z-80 or 8080A
environment will be pleased to find that the Commodore 128
supports it. A Z-80 microprocessor is built into the system and is
fully dedicated to the CP/M features that are briefly described in
Chapter 5.
Chapters 2 through 5 deal with the eight programming formats
available on the "stock" Commodore 128-BASIC (actually both
BASIC 2.0 and 7.0), DOS (the new Commodore disk operating sys
tem), the machine language monitor and 8502 machine/assembly lan
guage, and CP/Mand Z-80/8080A machine language programming.
Chapters 6 through 12 describe the individual features of the
Commodore 128 system. A reader who wishes to study sprite anima
tion or RS-232-C communications procedures, for example, will find
complete descriptions of those subjects in Chapters 8 and 12, re
spectively.
Chapter 13 is a memory map of the Commodore 128 system.
This chapter outlines the principal blocks of memory, describes the
most important registers, and summarizes the built-in Kernal routines
that are readily available to the programroer.
x Preface
Chapter 14 deals with procedures for rnanaging the entire 128K
of memory. Wherever possible, each principle cited in the hook is
first demonstrated in a format that should be familiar to most read
ers-in BASIC; then the sameprinciple is illustrated in termsof moni
tor and machine-language programming.
The use of many examples written in 8502 assembly language
directly reflects the fact that the Commodore 128 is designed to
encourage machine-language programming and calls to Kernal sub
routines.
Unlike much of the early literature dealing with the Commo
dore 128, no underlying assumption is made that the reader is already
familiar with the features and quirks of the earlier Commodore per
sonal computers, notably the Commodore 64.
I believe that paying twice the suggested retail price for this sys
tem would be a bargain. The Commodore 128 is a powerful system
that stands on its own merits and promises to engage a lot of users
who have no previous experience with earlier Commodore systems.
DAVID L. HEISERMAN
1
General
Oparating
Procedures
