Using 6502 assembly language : how anyone can program the Apple II

Description

Chapter 1 INTRODUCTION 1-1 Purpose of Manual 1-1 Scope of Manual 1-1 General 1-1 Chapter 2 SYMBOLISM 2-1 General 2-1 Bit Strings 2-3 Binary Arithmetic 2-8 Unsigned Integers 2-9 Nibbles (NYBBLES?), Bytes, and Words 2-10 Signed Integers 2-11 Hexadecimal Numbers 2-13 Radix and Other Nasty Diseases 2-14 ASCII Character Set 2-14 Using Bit Strings to Represent Instructions 2-16 Chapter 3 REGISTERS, INSTRUCTION FORMATS, AND ADDRESSING 3-1 General 3-1 Accumulator (A or ACC) 3-3 X-Register (X) 3-3 Y-Register (Y) 3-3 Stack Pointer (SP) 3-4 Program Status Word (P or PWS) 3-4 Program Counter (PC) 3-4 Instruction Format (6502) 3-4 Two and 3-Byte Instructions 3-6 6502 Addressing Modes 3-8 Chapter 4 SOME SIMPLE INSTRUCTIONS 4-1 General 4-1 Assembly Language Source Format 4-1 Introduction to Real Instructions 4-4 Register Increments and Decrements 4-8 Labels and Variables 4-9 Expressions in the Operand Field 4-11 Chapter 5 ASSEMBLY LANGUAGE 5-1 General 5-1 Example Program 5-2 JMP Instruction 5-3 Processor Status (P) Register 5-5 Break Flag (B) 5-6 Decimal Flag (D) 5-6 Interrupt Disable Flag (Z) 5-6 Condition Code Flags (N, V, Z, C) 5-7 Branch Instructions (6502) 5-9 Loops 5-10 Comparisons 5-11 IF/THEN Statement Simulation 5-14 FOR/NEXT Loop Revisited 5-14 Testing Boolean Values 5-18 Chapter 6 ARITHMETIC OPERATIONS 6-1 General 6-1 Unsigned Integer (Binary) Arithmetic 6-1 Subtraction 6-4 Signed Arithmetic 6-5 Signed Comparisons 6-7 Binary Coded Decimal Arithmetic 6-8 Unsigned BCD Arithmetic 6-8 Signed BCD Arithmetic 6-10 Arithmetic Review 6-10 Chapter 7 SUBROUTINES AND STACK PROCESSING 7-1 General 7-1 Variable Problems 7-4 Passing Parameters 7-13 Chapter 8 ARRAYS, ZERO PAGE, INDEXED, AND INDIRECT ADDRESSING 8-1 General 8-1 Zero Page Addressing 8-1 Arrays in Assembly Language 8-3 Initializing Arrays at Assembly Time 8-8 Using Index Registers to Access Array Elements 8-10 Indirect Addressing Mode 8-13 Indirect Indexed Addressing 8-16 Indexed Indirect Addressing Mode 8-18 Chapter 9 LOGICAL, MASKING, AND BIT OPERATIONS 9-1 General 9-1 Complement Function 9-2 AND Function 9-2 OR Function 9-3 EXCLUSIVE-OR Function 9-4 Bit String Operations 9-4 Instructions for Logical Operations 9-5 Masking Operations 9-7 Shift and Rotate Instructions 9-13 Shifting and Rotating Memory Locations 9-16 Using ASL to Perform Multiplication 9-17 Using Shifts to Unpack Data 9-19 Using Shifts and Rotates to Pack Data 9-20 Chapter 10 MULTIPLE-PRECISION OPERATIONS 10-1 General 10-1 Multiple-Precision Logical Operations 10-1 Multiple-Precision Shifts and Rotates 10-3 Multiple-Precision Logical Shift-Right Sequences 10-4 Multiple-Precision Rotate-Left Sequences 10-4 Multiple-Precision Rotate-Right Sequences 10-5 Multiple-Precision Unsigned Arithmetic 10-6 Multiple-Precision Unsigned Subtraction 10-8 Multiple-Precision Signed Arithmetic 10-9 Multiple-Precision Decimal Arithmetic 10-9 Multiple-Precision Increments 10-9 Multiple-Precision Decrements 10-10 Multiple-Precision Unsigned Comparisons 10-11 Signed Comparisons 10-14 Chapter 11 BASIC I/O 11-1 General 11-1 Character Output 11-1 Standard Output and Peripheral Devices 11-9 Character Input 11-11 Inputting a Line of Characters 11-13 Chapter 12 NUMERIC I/O 12-1 General 12-1 Hexadecimal Output 12-1 Outputting Byte Data as a Decimal Value 12-2 Outputting 16-Bit Unsigned Integers 12-4 Outputting Signed 16-Bit Integers 12-6 An Easy Method of Outputting Integers 12-6 Numeric Input 12-8 Unsigned Decimal Input 12-11 Signed Decimal Input 12-17 Chapter 13 MULTIPLICATION AND DIVISION 13-1 General 13-1 Multiplication 13-1 Division Algorithms 13-7 Chapter 14 STRING HANDLING OPERATIONS 14-1 String Handling 14-1 Declaring Literal Strings 14-5 String Assignments 14-5 String Functions 14-7 String Concatenation 14-9 Substring Operations 14-11 String Comparisons 14-12 Handling Arrays of Characters 14-17 Chapter 15 SPECIALIZED I/O 15-1 Apple I/O Structure 15-1 Chapter 16 AN INTRODUCTION TO SWEET-16 16-1 Sweet-16 16-2 Sweet-16 Hardware Requirements 16-10 Chapter 17 DEBUGGING 6502 MACHINE LANGUAGE PROGRAMS 17-1 General 17-1 GO Command (G) 17-2 Initializing Registers and Memory 17-3 Modifying Instruction Code (Patching) 17-6 Program Debugging Session 17-10 Appendix A APPLE II COMPUTER TABLES, CHARTS, AND GRAPHS A-1