INSTRUCTION SEQUENCE RESTRICTIONS
MOTOROLA
INSTRUCTION SET DETAILS
A - 305
A.9
INSTRUCTION SEQUENCE RESTRICTIONS
Due to the pipelined nature of the DSP56K central processor, there are certain instruc-
tion sequences that are forbidden and will cause undefined operation. Most of these
restricted sequences would cause contention for an internal resource, such as the stack
register. The DSP assembler will flag these as assembly errors.
Most of the following restrictions represent very unusual operations which probably
would never be used but are listed only for completeness.
Note: The DSP56K macro assembler is designed to recognize all restrictions and flag
them as errors at the source code level. Since many of these are instruction sequence
restrictions, they cannot be flagged as errors at the object code level such as when using
the DSP56K simulator’s single-line assembler. Therefore, if any changes are made at
the object code level using the simulator, the user should always re-assemble his pro-
gram at the source code level using the DSP56K macro assembler to verify that no
restricted instruction sequences have been generated.
Note 1: wx = external X memory access wait states
wy = external Y memory access wait states
wp = external P memory access wait states
wio = external I/O memory access wait states
Note 2: wx, wy, wp, and wio are programmable from 0 - 15 wait states in the port A bus control register (BCR).
Access
Type
X Mem
Access
Y Mem
Access
P Mem
Access
I/O
Access
+ ax
Cycle
+ ay
Cycle
+ ap
Cycle
+ aio
Cycle
+ axy
Cycle
X:
Int
—
—
—
0
—
—
—
—
X:
Ext
—
—
—
wx
—
—
—
—
Y:
—
Int
—
—
—
0
—
—
—
Y:
—
Ext
—
—
—
wy
—
—
—
P:
—
—
Int
—
—
—
0
—
—
P:
—
—
Ext
—
—
—
wp
—
—
I/O:
—
—
—
Int
—
—
—
0
—
I/O:
—
—
—
Ext
—
—
—
wio
—
L: XY:
Int
Int
—
—
—
—
—
—
0
L: XY:
Int
Ext
—
—
—
—
—
—
wy
L: XY:
Ext
Int
—
—
—
—
—
—
wx
L: XY:
Ext
Ext
—
—
—
—
—
—
2 + wx + wy
Table A-14 Memory Access Timing Summary
Summary of Contents for DSP56K
Page 12: ...xii LIST of TABLES MOTOROLA List of Tables Continued Table Page Number Title Number ...
Page 13: ...MOTOROLA DSP56K FAMILY INTRODUCTION 1 1 SECTION 1 DSP56K FAMILY INTRODUCTION ...
Page 31: ...MOTOROLA DATA ARITHMETIC LOGIC UNIT 3 1 SECTION 3 DATA ARITHMETIC LOGIC UNIT ...
Page 50: ...DATA ALU SUMMARY 3 20 DATA ARITHMETIC LOGIC UNIT MOTOROLA ...
Page 51: ...MOTOROLA ADDRESS GENERATION UNIT 4 1 SECTION 4 ADDRESS GENERATION UNIT ...
Page 77: ...MOTOROLA PROGRAM CONTROL UNIT 5 1 SECTION 5 PROGRAM CONTROL UNIT ...
Page 124: ...INSTRUCTION GROUPS 6 30 INSTRUCTION SET INTRODUCTION MOTOROLA ...
Page 125: ...MOTOROLA PROCESSING STATES 7 1 SECTION 7 PROCESSING STATES STOP WAIT EXCEPTION NORMAL RESET ...
Page 167: ...STOP PROCESSING STATE MOTOROLA PROCESSING STATES 7 43 ...
Page 168: ...STOP PROCESSING STATE 7 44 PROCESSING STATES MOTOROLA ...
Page 169: ...MOTOROLA PORT A 8 1 SECTION 8 PORT A ...
Page 176: ...PORT A INTERFACE 8 8 PORT A MOTOROLA ...
Page 177: ...MOTOROLA PLL CLOCK OSCILLATOR 9 1 SECTION 9 PLL CLOCK OSCILLATOR x x d Φ VCO ...
Page 191: ...10 2 ON CHIP EMULATION OnCE MOTOROLA SECTION 10 ON CHIP EMULATION OnCE ...
Page 218: ...USING THE OnCE MOTOROLA ON CHIP EMULATION OnCE 10 29 ...
Page 604: ...INSTRUCTION ENCODING A 338 INSTRUCTION SET DETAILS MOTOROLA ...
Page 605: ...MOTOROLA BENCHMARK PROGRAMS B 1 APPENDIX B BENCHMARK PROGRAMS T T T T T P1 P3 P2 P4 T T T ...
Page 609: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 5 ...
Page 611: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 7 ...
Page 613: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 9 ...
Page 615: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 11 ...