Volume 4: IA-32 Intel
®
MMX™ Technology Instruction Reference
4:405
PACKSSWB/PACKSSDW—Pack with Signed Saturation
Description
Packs and saturates signed words into bytes (PACKSSWB) or signed doublewords into
words (PACKSSDW). The PACKSSWB instruction packs 4 signed words from the
destination operand (first operand) and 4 signed words from the source operand
(second operand) into 8 signed bytes in the destination operand. If the signed value of
a word is beyond the range of a signed byte (that is, greater than 7FH or less than
80H), the saturated byte value of 7FH or 80H, respectively, is stored into the
destination.
The PACKSSDW instruction packs 2 signed doublewords from the destination operand
(first operand) and 2 signed doublewords from the source operand (second operand)
into 4 signed words in the destination operand (see
). If the signed value of a
doubleword is beyond the range of a signed word (that is, greater than 7FFFH or less
than 8000H), the saturated word value of 7FFFH or 8000H, respectively, is stored into
the destination.
The destination operand for either the PACKSSWB or PACKSSDW instruction must be an
MMX technology register; the source operand may be either an MMX technology
register or a quadword memory location.
Operation
IF instruction is PACKSSWB
THEN
DEST(7..0)
SaturateSignedWordToSignedByte DEST(15..0);
DEST(15..8)
SaturateSignedWordToSignedByte DEST(31..16);
DEST(23..16)
SaturateSignedWordToSignedByte DEST(47..32);
DEST(31..24)
SaturateSignedWordToSignedByte DEST(63..48);
DEST(39..32)
SaturateSignedWordToSignedByte SRC(15..0);
DEST(47..40)
SaturateSignedWordToSignedByte SRC(31..16);
DEST(55..48)
SaturateSignedWordToSignedByte SRC(47..32);
DEST(63..56)
SaturateSignedWordToSignedByte SRC(63..48);
Opcode
Instruction
Description
0F 63 /r
PACKSSWB
mm,
mm/m64
Packs and saturate pack 4 signed words from
mm
and 4
signed words from
mm/m64
into 8 signed bytes in
mm
.
0F 6B /r
PACKSSDW
mm,
mm/m64
Pack and saturate 2 signed doublewords from
mm
and 2
signed doublewords from
mm/m64
into 4 signed words in
mm
.
Figure 3-3.
Operation of the PACKSSDW Instruction
mm/m64
mm
D
C
B
A
D’
C’
B’
A’
mm
PACKSSDW mm, mm/m64
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: ......
Page 248: ...236 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
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 ...