INSTRUCTION DESCRIPTIONS
A - 276
INSTRUCTION SET DETAILS
MOTOROLA
Operation:
Assembler Syntax:
D–S
➞
D (parallel move)
SUB S,D (parallel move)
Description: Subtract the source operand S from the destination operand D and store
the result in the destination operand D. Words (24 bits), long words (48 bits), and accu-
mulators (56 bits) may be subtracted from the destination accumulator.
Note: The carry bit is set correctly using word or long-word source operands if the exten-
sion register of the destination accumulator (A2 or B2) is the sign extension of bit 47 of
the destination accumulator (A or B). The carry bit is always set correctly using accumu-
lator source operands.
Example:
:
SUB X1,A X:(R2)+N2,R0
;24-bit subtract, load R0, update R2
:
Explanation of Example: Prior to execution, the 24-bit X1 register contains the value
$000003, and the 56-bit A accumulator contains the value $00:000058:242424. The
SUB instruction automatically appends the 24-bit value in the X1 register with 24 LS
zeros, sign extends the resulting 48-bit long word to 56 bits, and subtracts the result from
the 56-bit A accumulator. Thus, 24-bit operands are subtracted from the MSP portion of
A or B (A1 or B1) because all arithmetic instructions assume a fractional, twos comple-
ment data representation. Note that 24-bit operands can be subtracted from the LSP por-
tion of A or B (A0 or B0) by loading the 24-bit operand into X0 or Y0, forming a 48-bit
word by loading X1 or Y1 with the sign extension of X0 or Y0, and executing a SUB X,A
or SUB Y,A instruction.
SUB
Subtract
SUB
Before Execution
After Execution
X1
$000003
A
A
$00:000058:242424
$00:000055:242424
$000003
X1
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 ...