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PROGRAMERS REFERENCE MANUAL

APPENDIX B
IA MMX™ INSTRUCTION FORMATS AND ENCODINGS

B.1 Instruction Formats

All MMX instructions, except the EMMS instruction, use the same format similar as the two-byte Intel Architecture integer operations. Details of subfield encodings within these formats are presented below.

Table B­1. Encoding of Granularity of Data (gg) Field
gg
Granularity of Data
00
packed bytes
01
packed words
10
packed doublewords
11
quadword

Table B­2. Encoding of 32-bit General Purpose (reg) Field for Register-to-Register Operations
reg Field
Register Selected
000
EAX
001
ECX
010
EDX
011
EBX
100
ESP
101
EBP
110
ESI
111
EDI

NOTE: For register-to-register operations, the decoding of integer registers is independent of processor mode. For register-to-memory operations, the effective address is calculated based on the processor mode in effect.

Table B­3. Encoding of 64-bit MMX™ Register (mmxreg) Field
mmxreg Field
MMX Register Selected
000
mm0
001
mm1
010
mm2
011
mm3
100
mm4
101
mm5
110
mm6
111
mm7

For more details, see Table 25-2, Table 25-3, and Appendix F of the Pentium® Processor Family Developer's Manual.

B.2 Instruction Encodings and Datatype Cross-Reference

For each MMX instruction, Table B­4 lists instruction encodings and the datatypes supported-byte (B), word (W), doubleword (DW), and quadword (QW).

O
 = output
I
 = input
S
 = signed saturation
U
 = unsigned saturation
n/a
 = not applicable
Figure B-1. Key to Codes for Datatype Cross-Reference

Table B­4. IA MMX™ Instruction Formats and Encodings
Instruction
Format
B
W
DW
QW
EMMS - Empty MMX state 0000 1111:01110111
n/a
n/a
n/a
n/a
MOVD - Move doubleword
N
N
Y
N
reg to mmxreg0000 1111:01101110: 11 mmxreg reg
reg from mmxreg0000 1111:01111110: 11 mmxreg reg
mem to mmxreg0000 1111:01101110: mod mmxreg r/m
mem from mmxreg0000 1111:01111110: mod mmxreg r/m
MOVQ - Move quadword
N
N
N
Y
mmxreg2 to mmxreg10000 1111:01101111: 11 mmxreg1 mmxreg2
mmxreg2 from mmxreg1 0000 1111:01111111: 11 mmxreg1 mmxreg2
mem to mmxreg0000 1111:01101111: mod mmxreg r/m
mem from mmxreg0000 1111:01111111: mod mmxreg r/m
Table B­4. IA MMX™ Instruction Formats and Encodings (Contd.)
Instruction
Format
B
W
DW
QW
PACKSSDW1 - Pack dword to word data (signed with saturation)
n/a
O
I
n/a
mmxreg2 to mmxreg10000 1111:01101011: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:01101011: mod mmxreg r/m
PACKSSWB1 - Pack word to byte data (signed with saturation)
O
I
n/a
n/a
mmxreg2 to mmxreg10000 1111:01100011: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:01100011: mod mmxreg r/m
PACKUSWB1 - Pack word to byte data (unsigned with saturation)
O
I
n/a
n/a
mmxreg2 to mmxreg10000 1111:01100111: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:01100111: mod mmxreg r/m
PADD - Add with wrap-around
Y
Y
Y
N
mmxreg2 to mmxreg10000 1111: 111111gg: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111: 111111gg: mod mmxreg r/m
Table B­4. IA MMX™ Instruction Formats and Encodings (Contd.)
Instruction
Format
B
W
DW
QW
PADDS - Add signed with saturation
Y
Y
N
N
mmxreg2 to mmxreg10000 1111: 111011gg: 11 mmxreg1 mmxreg2
memory to reg0000 1111: 111011gg: mod reg r/m
PADDUS - Add unsigned with saturation
Y
Y
N
N
mmxreg2 to mmxreg10000 1111: 110111gg: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111: 110111gg: mod mmxreg r/m
PAND - Bitwise And
N
N
N
Y
mmxreg2 to mmxreg10000 1111:11011011: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:11011011: mod mmxreg r/m
PANDN - Bitwise AndNot
N
N
N
Y
mmxreg2 to mmxreg10000 1111:11011111: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:11011111: mod mmxreg r/m
PCMPEQ - Packed compare for equality
Y
Y
Y
N
mmxreg2 with mmxreg1 0000 1111:011101gg: 11 mmxreg1 mmxreg2
memory with mmxreg0000 1111:011101gg: mod mmxreg r/m
Table B­4. IA MMX™ Instruction Formats and Encodings (Contd.)
Instruction
Format
B
W
DW
QW
PCMPGT - Packed compare greater (signed)
Y
Y
Y
N
mmxreg2 with mmxreg1 0000 1111:011001gg: 11 mmxreg1 mmxreg2
memory with mmxreg0000 1111:011001gg: mod mmxreg r/m
PMADD - Packed multiply add
n/a
I
O
n/a
mmxreg2 to mmxreg10000 1111:11110101: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:11110101: mod mmxreg r/m
PMULH - Packed multiplication
N
Y
N
N
mmxreg2 to mmxreg10000 1111:11100101: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:11100101: mod mmxreg r/m
PMULL - Packed multiplication
N
Y
N
N
mmxreg2 to mmxreg10000 1111:11010101: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:11010101: mod mmxreg r/m
POR - Bitwise Or
N
N
N
Y
mmxreg2 to mmxreg10000 1111:11101011: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:11101011: mod mmxreg r/m
Table B­4. IA MMX™ Instruction Formats and Encodings (Contd.)
Instruction
Format
B
W
DW
QW
PSLL2 - Packed shift left logical
N
Y
Y
Y
mmxreg2 by mmxreg10000 1111:111100gg: 11 mmxreg1 mmxreg2
mmxreg by memory0000 1111:111100gg: 11 mmxreg r/m
mmxreg by immediate 0000 1111:011100gg: 11 110 mmxreg: imm8 data
PSRA2 - Packed shift right arithmetic
N
Y
Y
N
mmxreg2 by mmxreg10000 1111:111000gg: 11 mmxreg1 mmxreg2
mmxreg by memory0000 1111:111000gg: 11 mmxreg r/m
mmxreg by immediate 0000 1111:011100gg: 11 100 mmxreg: imm8 data
PSRL2 - Packed shift right logical
N
Y
Y
Y
mmxreg2 by mmxreg10000 1111:110100gg: 11 mmxreg1 mmxreg2
mmxreg by memory0000 1111:110100gg: 11 mmxreg r/m
mmxreg by immediate 0000 1111:011100gg: 11 010 mmxreg: imm8 data
PSUB - Subtract with wrap-around
Y
Y
Y
N
mmxreg2 to mmxreg10000 1111:111110gg: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:111110gg: mod mmxreg r/m
Table B­4. IA MMX™ Instruction Formats and Encodings (Contd.)
Instruction
Format
B
W
DW
QW
PSUBS - Subtract signed with saturation
Y
Y
N
N
mmxreg2 to mmxreg10000 1111:111010gg: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:111010gg: mod mmxreg r/m
PSUBUS - Subtract unsigned with saturation
Y
Y
N
N
mmxreg2 to mmxreg10000 1111:110110gg: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:110110gg: mod mmxreg r/m
PUNPCKH - Unpack high data to next larger type
Y
Y
Y
N
mmxreg2 to mmxreg10000 1111:011010gg: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:011010gg: mod mmxreg r/m
PUNPCKL - Unpack low data to next larger type
Y
Y
Y
N
mmxreg2 to mmxreg10000 1111:011000gg: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:011000gg: mod mmxreg r/m
Table B­4. IA MMX™ Instruction Formats and Encodings (Contd.)
Instruction
Format
B
W
DW
QW
PXOR - Bitwise Xor
N
N
N
Y
mmxreg2 to mmxreg10000 1111:11101111: 11 mmxreg1 mmxreg2
memory to mmxreg0000 1111:11101111: mod mmxreg r/m

NOTE:

1. The PACK instructions perform saturation from signed packed data of one type to signed or unsigned data of the next smaller type.

2. The format of shift instructions has one additional format to support shifting by immediate shift-counts. The shift operations are not supported equally for all data types.
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