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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
Содержание ITANIUM ARCHITECTURE
Страница 1: ......
Страница 7: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 199: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Страница 269: ...4 262 Volume 4 Base IA 32 Instruction Reference LES Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 270: ...Volume 4 Base IA 32 Instruction Reference 4 263 LFS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 273: ...4 266 Volume 4 Base IA 32 Instruction Reference LGS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 288: ...Volume 4 Base IA 32 Instruction Reference 4 281 LSS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 352: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Страница 368: ...Volume 4 Base IA 32 Instruction Reference 4 361 SHL SHR Shift Instructions See entry for SAL SAR SHL SHR ...
Страница 373: ...4 366 Volume 4 Base IA 32 Instruction Reference SIDT Store Interrupt Descriptor Table Register See entry for SGDT SIDT ...
Страница 589: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Страница 590: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Страница 591: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 603: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...
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