3-497
INSTRUCTION SET REFERENCE
PCMPGTB/PCMPGTW/PCMPGTDPacked Compare for Greater
Than
Description
These instructions compare the individual signed data elements (bytes, words, or doublewords)
in the destination operand (first operand) to the corresponding signed data elements in the source
operand (second operand) (refer to Figure 3-62). If a data element in the destination operand is
greater than its corresponding data element in the source operand, the data element in the desti-
nation operand is set to all ones; otherwise, it is set to all zeroes. 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.
The PCMPGTB instruction compares the signed bytes in the destination operand to the corre-
sponding signed bytes in the source operand, with the bytes in the destination operand being set
according to the results.
The PCMPGTW instruction compares the signed words in the destination operand to the corre-
sponding signed words in the source operand, with the words in the destination operand being
set according to the results.
The PCMPGTD instruction compares the signed doublewords in the destination operand to the
corresponding signed doublewords in the source operand, with the doublewords in the destina-
tion operand being set according to the results.
Opcode
Instruction
Description
0F 64 /r
PCMPGTB mm,
mm/m64
Compare packed bytes in mm with packed bytes in
mm/m64 for greater value.
0F 65 /r
PCMPGTW mm,
mm/m64
Compare packed words in mm with packed words in
mm/m64 for greater value.
0F 66 /r
PCMPGTD mm,
mm/m64
Compare packed doublewords in mm with packed
doublewords in mm/m64 for greater value.
Figure 3-62. Operation of the PCMPGTW Instruction
PCMPGTW mm, mm/m64
mm
mm/m64
mm
0000000000000000
0000000000000000
0000000000000000
0000000000000001
0000000000000000
1111111111111111
0000000000000111
0111000111000111
0000000000000000
0111000111000111
0111000111000111
0000000000000000
False
False
True
False
3006021
>
>
>
>
