Machine Language for the Commodore 64 and Other Commodore Computers

Note to Readers                                   vi
Preface                                           vii
Introduction                                      ix
1   First Concepts                                 1
    The Inner Workings of Microcomputers
    Computer Notation: Binary and Hexadecimal
    The 650x's Inner Architecture
    Beginning Use of a Machine Language Monitor
    A Computer's "Memory Layout"
    First Machine Language Commands
    Writing and Entering a Simple Program
2   Controlling Output                            23
    Calling Machine Language Subroutines
    The PRINT Subroutine
    Immediate Addressing
    Calling Machine Language from BASIC
    Tiny Assembler Programs
    Indexed Addressing
    Simple Loops
    Disassembly
3   Flags, Logic, and Input                       39
    Flags that hold Status Information
    Testable Flags: Z, C, N, and V
    Signed Numbers
    The Status Register
    First Concepts of Interrupt
    Logical Operators: OR, AND, EOR
    The GETIN Subroutine for Input
    The STOP Subroutine
4   Numbers, Arithmetic, and Subroutines           57
    Numbers: Signed and Unsigned
    Big Numbers: Multiple Bytes
    Arithmetic: Add and Subtract
    Rotate and Shift Instructions
    Multiplication
    Home-Grown Subroutines
5   Address Modes                                  71
    Non-addresses: Implied, Immediate, Register
    Absolute and Zero Page
    Indexing
    The Relative Address for Branches
    Indirect Addressing
    Indirect, Indexed
6   Linking BASIC and Machine Language              91
    Where To Put a Machine Language Program
    Basic Memory Layout
    Loading and the SOV Pointer
    Basic Variables: Fixed, Floating, and String
    Exchanging Data with BASIC
7   Stack, USR, Interrupt, and Wedge               111
    The Stack for Temporary Storage
    USR: An Alternative to SYS
    Interrupts: IRQ, NMI, and BRK
    The IA Chips: PIA and VIA
    Infiltrating BASIC: The Wedge
8. Timing, Input/Output, and Conclusion            131
    How To Estimate the Speed of Your Program
    Input and Output from Tape, Disk, Printer
    Review of Instructions
    Debugging
    Symbolic Assemblers
    Where To Go from Here
Appendix A The 6502/6510/6509/7501 Instruction
           Set                                   147
Appendix B Some Characteristics of Commodore
           Machines                              155
Appendix C Memory Maps                           161
Appendix D Character Sets                        215
Appendix E Exercises for Alternative Commodore
           Machines                              225
Appendix F Floating Point Formats'               231
Appendix G Uncrashing                            233
Appendix H A Do-It-Yourself Supermon             237
Appendix I IA Chip Information                   245
Appendix J Disk User's Guide                    309
Glossary                                         317
Index                                            322