Motorola DSP56305 User Manual download pdf (Page 94)

Compact Opcode Use

Special Instructions

MOTOROLA Optimizing DSP56300/DSP56600 Applications 7-9

7.4.3 Clearing Registers

It is often needed to clear a certain register or accumulator in the

code. Optimization can be accomplished in this area, also. Example:

move r1,r0

move #0,a

move y0,a0

This example can be optimized by using the CLR instructions and

by combining a move instruction with the CLR to a parallel opcode:

clr a r1,r0

move y0,a0

Another example:

add x0,a

clr b

move y0,b0

This can be optimized by:

add x0,a #0,b

move y0,b0

1 2 ... 89 90 91 92 93 94 95 96 97 98 99 ... 111 112

DSP56300/DSP56600 1
Digital Signal 1
Processors 1
TABLE OF CONTENTS 2
LIST OF FIGURES 6
LIST OF TABLES 7
INTRODUCTION 8
1.2 DSP56600 CORE FAMILY 9
Table 1-1 11
Introduction 12
Description and Use 13
Application Note Structure 14
1.4.3 Appendixes 15
DATA OPERATIONS 16
DSP56300 Family Manual 21
2.3 THE MAX INSTRUCTION 22
2.4 USING THE BARREL SHIFTER 23
Data Operations 24
Using the barrel shifter 24
DSP56300 26
DSP56600 Family 26
Double precision arithmetic 27
INSTRUCTIONS 28
PROGRAM CONTROL 30
Program Control 31
Hardware Loops 31
3.2 THE HARDWARE STACK 32
DSP56600 Family Manuals 35
3.3 USING THE STACK EXTENSION 36
Using the Stack Extension 37
EXTENSION 39
Conditional DALU Instructions 40
3.6 PC RELATIVE INSTRUCTIONS 42
DSP56600 Family Manual 43
3.7 USING FAST INTERRUPTS 46
Using Fast Interrupts 48
USING THE DMA 50
Using the DMA 51
Using Slow, Low-Cost Memories 54
4.4 SERVICING A PERIPHERAL 55
Servicing a Peripheral 56
Section 5 62
5.1 THE INSTRUCTION CACHE 62
5.1.1 Cache Sectors 64
The Instruction Cache 65
5.1.3 Cache Burst Mode 67
5.2 MEMORY SWITCH 70
Memory Switch 71
5.3 USING THE BOOTSTRAP ROM 72
Using the Bootstrap ROM 73
PIPELINE INTERLOCKS 74
Pipeline Interlocks 75
Data ALU Pipeline Interlocks 75
DSP56000 Family Manual 76
INTERLOCKS 80
Interlocks 80
6.3 STACK EXTENSION DELAYS 81
Interlocks? 83
COMPACT OPCODE USE 86
Instructions 87
Compact Opcode Use 89
Cycle Count of an Instruction 89
7.2 ADDRESSING MODES 90
7.2.2 Short Addressing Mode 91
7.2.3 Short Immediate Mode 91
7.2.5 Register Addressing 92
7.2.6 Word Count 92
7.3 PERIPHERAL ADDRESSING 92
7.4 SPECIAL INSTRUCTIONS 93
7.4.1 Dual Data Spaces 93
7.4.3 Clearing Registers 94
Special Instructions 95
SAVING POWER 96
A.1.2 Stop Standby Mode 97
A.1.3 Low-Power Clock Divider 97
Saving Power 98
Disabling Functional Blocks 98
DEBUG AND TEST SUPPORT 100
B.2 JTAG PORT FEATURES 101
B.3 ADDRESS TRACING 102
Debug and Test Support 103
Address Tracing 103
USING THE PROFILER 104
C.3 THE PROFILING REPORT 105
C.3.1 Basic Report 105
C.3.2 Symbol Report 106
Using the Profiler 107
C.3.4 Code Coverage Report 108
C.3.5 Basic Subroutine Report 109
C.3.8 Subroutine Call Report 111
C.4 USING THE PROFILE REPORT 111
How to reach us: 112

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