Motorola DSP56000, 24-Bit Digital Signal Processor Appendix a Introduction, Instruction Guide

APPENDIX A INTRODUCTION

A.1 APPENDIX A INTRODUCTION

This appendix contains detailed information about each instruction in the DSP56K instruction set. It presents an instruction guide to help the user understand the individual instruction descriptions and follows with sections on notation and addressing modes. The instructions are then discussed in alphabetical order.

A.2 INSTRUCTION GUIDE

The following information is included in each instruction description with the goal of mak- ing each description self-contained:

1.Name and Mnemonic: The mnemonic is highlighted in bold type for easy refer- ence.

2.Assembler Syntax and Operation: For each instruction syntax, the corresponding operation is symbolically described. If there are several operations indicated on a single line in the operation field, those operations do not necessarily occur in the order shown but are generally assumed to occur in parallel. If a parallel data move is allowed, it will be indicated in parenthesis in both the assembler syntax and oper- ation fields. If a letter in the mnemonic is optional, it will be shown in parenthesis in the assembler syntax field.

3.Description: A complete text description of the instruction is given together with any special cases and/or condition code anomalies of which the user should be aware when using that instruction.

4.Example: An example of the use of the instruction is given. The example is shown in DSP56K assembler source code format. Most arithmetic and logical instruction examples include one or two parallel data moves to illustrate the many types of par- allel moves that are possible. The example includes a complete explanation, which discusses the contents of the registers referenced by the instruction (but not those referenced by the parallel moves) both before and after the execution of the instruc- tion. Most examples are designed to be easily understood without the use of a cal- culator.

5.Condition Codes: The status register is depicted with the condition code bits which can be affected by the instruction highlighted in bold type. Not all bits in the status register are used. Those which are reserved are indicated with a double asterisk and are read as zeros.

6.Instruction Format: The instruction fields, the instruction opcode, and the instruc- tion extension word are specified for each instruction syntax. When the extension

MOTOROLA INSTRUCTION SET DETAILS A - 3