4:446
Volume 4: IA-32 Intel
®
MMX™ Technology Instruction Reference
PSUBB/PSUBW/PSUBD—Packed Subtract
Description
Subtracts the individual data elements (bytes, words, or doublewords) of the source
operand (second operand) from the individual data elements of the destination operand
(first operand). (See
.) If the result of a subtraction exceeds the range for
the specified data type (overflows), the result is wrapped around, meaning that the
result is truncated so that only the lower (least significant) bits of the result are
returned (that is, the carry is ignored).
The destination operand must be an MMX technology register; the source operand can
be either an MMX technology register or a quadword memory location.
The PSUBB instruction subtracts the bytes of the source operand from the bytes of the
destination operand and stores the results to the destination operand. When an
individual result is too large to be represented in 8 bits, the lower 8 bits of the result
are written to the destination operand and therefore the result wraps around.
The PSUBW instruction subtracts the words of the source operand from the words of the
destination operand and stores the results to the destination operand. When an
individual result is too large to be represented in 16 bits, the lower 16 bits of the result
are written to the destination operand and therefore the result wraps around.
The PSUBD instruction subtracts the doublewords of the source operand from the
doublewords of the destination operand and stores the results to the destination
operand. When an individual result is too large to be represented in 32 bits, the lower
32 bits of the result are written to the destination operand and therefore the result
wraps around.
Opcode
Instruction
Description
0F F8 /r
PSUBB
mm, mm/m64
Subtract packed bytes in
mm/m64
from packed bytes in
mm
.
0F F9 /r
PSUBW
mm, mm/m64
Subtract packed words in
mm/m64
from packed words in
mm
.
0F FA /r
PSUBD
mm, mm/m64
Subtract packed doublewords in
mm/m64
from packed
doublewords in
mm
.
Figure 3-19. Operation of the PSUBW Instruction
3006028
PSUBW mm, mm/m64
mm
mm/m64
mm
1000000000000000
0000000000000001
0111111111111111
0111111100111000
1110100011111001
1001011000111111
–
–
–
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Summary of Contents for ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS VOLUME 3 REV 2.3
Page 1: ......
Page 11: ...x Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 13: ...1 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 33: ...1 22 Volume 1 Part 1 Introduction to the Intel Itanium Architecture ...
Page 57: ...1 46 Volume 1 Part 1 Execution Environment ...
Page 147: ...1 136 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 149: ...1 138 Volume 1 Part 2 About the Optimization Guide ...
Page 191: ...1 180 Volume 1 Part 2 Predication Control Flow and Instruction Stream ...
Page 230: ......
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Page 250: ...2 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 264: ...2 16 Volume 2 Part 1 Intel Itanium System Environment ...
Page 380: ...2 132 Volume 2 Part 1 Interruptions ...
Page 398: ...2 150 Volume 2 Part 1 Register Stack Engine ...
Page 486: ...2 238 Volume 2 Part 1 IA 32 Interruption Vector Descriptions ...
Page 750: ...2 502 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 754: ...2 506 Volume 2 Part 2 About the System Programmer s Guide ...
Page 796: ...2 548 Volume 2 Part 2 Interruptions and Serialization ...
Page 808: ...2 560 Volume 2 Part 2 Context Management ...
Page 842: ...2 594 Volume 2 Part 2 Floating point System Software ...
Page 850: ...2 602 Volume 2 Part 2 IA 32 Application Support ...
Page 862: ...2 614 Volume 2 Part 2 External Interrupt Architecture ...
Page 870: ...2 622 Volume 2 Part 2 Performance Monitoring Support ...
Page 891: ......
Page 1099: ...3 200 Volume 3 Instruction Reference padd Interruptions Illegal Operation fault ...
Page 1295: ...3 396 Volume 3 Resource and Dependency Semantics ...
Page 1296: ......
Page 1302: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 1494: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Page 1647: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Page 1884: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Page 1885: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Page 1886: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 1898: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...