모두의 코드
PSHUFW (Intel x86/64 assembly instruction)

작성일 : 2020-09-01 이 글은 573 번 읽혔습니다.

PSHUFW

Shuffle Packed Words

참고 사항

아래 표를 해석하는 방법은 x86-64 명령어 레퍼런스 읽는 법 글을 참조하시기 바랍니다.

Opcode/
Instruction

Op/
En

64-Bit
Mode

Compat/
Leg Mode

Description

0F 70 /r ib
PSHUFW mm1 mm2/m64 imm8

RMI

Valid

Valid

Shuffle the words in mm2/m64 based on the encoding in imm8 and store the result in mm1.

Instruction Operand Encoding

Op/En

Operand 1

Operand 2

Operand 3

Operand 4

RMI

ModRM:reg (w)

ModRM:r/m (r)

imm8

NA

Description

Copies words from the source operand (second operand) and inserts them in the destination operand (first operand) at word locations selected with the order operand (third operand). This operation is similar to the opera-tion used by the PSHUFD instruction, which is illustrated in Figure 4-16. For the PSHUFW instruction, each 2-bit field in the order operand selects the contents of one word location in the destination operand. The encodings of the order operand fields select words from the source operand to be copied to the destination operand.

The source operand can be an MMX technology register or a 64-bit memory location. The destination operand is an MMX technology register. The order operand is an 8-bit immediate. Note that this instruction permits a word in the source operand to be copied to more than one word location in the destination operand.

In 64-bit mode, using a REX prefix in the form of REX.R permits this instruction to access additional registers (XMM8-XMM15).

Operation

DEST[15:0] <- (SRC >> (ORDER[1:0] * 16))[15:0];
DEST[31:16] <- (SRC >> (ORDER[3:2] * 16))[15:0];
DEST[47:32] <- (SRC >> (ORDER[5:4] * 16))[15:0];
DEST[63:48] <- (SRC >> (ORDER[7:6] * 16))[15:0];

Intel C/C++ Compiler Intrinsic Equivalent

PSHUFW : __m64 _mm_shuffle_pi16(__m64 a, int n)

Flags Affected

None.

Numeric Exceptions

None.

Other Exceptions

See Table 22-7, "Exception Conditions for SIMD/MMX Instructions with Memory Reference," in the Intel(R) 64 and IA-32 Architectures Software Developer's Manual, Volume 3A.

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