Intel ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS MANUAL VOLUME 1 REV 2.3 Manual page 1725

PCMPEQB/PCMPEQW/PCMPEQD—Packed Compare for Equal
Opcode
0F 74 /r
0F 75 /r
0F 76 /r
Description
Compares the individual data elements (bytes, words, or doublewords) in the
destination operand (first operand) to the corresponding data elements in the source
operand (second operand). (See
corresponding data element in the destination operand is set to all ones; otherwise, it is
set to all zeros. The destination operand must be an MMX technology register; the
source operand may be either an MMX technology register or a 64-bit memory location.
Figure 3-10.
mm
mm/m64
mm
The PCMPEQB instruction compares the bytes in the destination operand to the
corresponding bytes in the source operand, with the bytes in the destination operand
being set according to the results.
The PCMPEQW instruction compares the words in the destination operand to the
corresponding words in the source operand, with the words in the destination operand
being set according to the results.
The PCMPEQD instruction compares the doublewords in the destination operand to the
corresponding doublewords in the source operand, with the doublewords in the
destination operand being set according to the results.
®
Volume 4: IA-32 Intel MMX™ Technology Instruction Reference
Instruction
PCMPEQB mm, mm/m64
PCMPEQW mm, mm/m64
PCMPEQD mm, mm/m64
Figure
Operation of the PCMPEQW Instruction
PCMPEQW mm, mm/m64
0000000000000000 0000000000000001
==
0000000000000000 0000000000000000
True
1111111111111111 0000000000000000
Description
Compare packed bytes in mm/m64 with packed bytes in mm for
equality.
Compare packed words in mm/m64 with packed words in mm for
equality.
Compare packed doublewords in mm/m64 with packed
doublewords in mm for equality.
3-10.) If a pair of data elements are equal, the
0000000000000111
== ==
0111000111000111
False False
0000000000000000
0111000111000111
==
0111000111000111
True
1111111111111111
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