PSHUFLW

Shuffle Packed Low Words

stableVMJITAOTinstruction

Encodings

Opcode	Instruction	Op/En	64-bit	Compat/Legacy	Description
`F2 0F 70 /r ib`	`PSHUFLW xmm1, xmm2/m128, imm8`	A	Valid	Valid	Shuffle the low words in xmm2/m128 based on the encoding in imm8 and store the result in xmm1.
`VEX.128.F2.0F.WIG 70 /r ib`	`VPSHUFLW xmm1, xmm2/m128, imm8`	A	Valid	Valid	Shuffle the low words in xmm2/m128 based on the encoding in imm8 and store the result in xmm1.
`VEX.256.F2.0F.WIG 70 /r ib`	`VPSHUFLW ymm1, ymm2/m256, imm8`	A	Valid	Valid	Shuffle the low words in ymm2/m256 based on the encoding in imm8 and store the result in ymm1.
`EVEX.128.F2.0F.WIG 70 /r ib`	`VPSHUFLW xmm1 {k1}{z}, xmm2/m128, imm8`	B	Valid	Valid	Shuffle the low words in xmm2/m128 based on AVX512BW) OR the encoding in imm8 and store the result in AVX10.1 xmm1 under write mask k1.
`EVEX.256.F2.0F.WIG 70 /r ib`	`VPSHUFLW ymm1 {k1}{z}, ymm2/m256, imm8`	B	Valid	Valid	Shuffle the low words in ymm2/m256 based on AVX512BW) OR the encoding in imm8 and store the result in AVX10.1 ymm1 under write mask k1.
`EVEX.512.F2.0F.WIG 70 /r ib`	`VPSHUFLW zmm1 {k1}{z}, zmm2/m512, imm8`	B	Valid	Valid	Shuffle the low words in zmm2/m512 based on OR AVX10.1 the encoding in imm8 and store the result in zmm1 under write mask k1.

Operand encoding

Each mode is a value of the Op/En column above. It says which field of the encoded instruction carries each operand, in the order they are written, and whether the instruction reads it, writes it or both.

A

modrm.reg escrituraModRM byte, reg field (bits 5-3)
modrm.rm lecturaModRM byte, r/m field (bits 2-0); with the SIB byte and the displacement when the mod field asks for them
imm8immediate byte after the instruction

B

modrm.reg escrituraModRM byte, reg field (bits 5-3)
modrm.rm lecturaModRM byte, r/m field (bits 2-0); with the SIB byte and the displacement when the mod field asks for them
imm8immediate byte after the instruction

Tupla: Full Mem

Measured cost

Loading measurements from arch-data...

Description

Copies words from the low quadword of a 128-bit lane of the source operand and inserts them in the low quadword of the destination operand at word locations (of the respective lane) selected with the immediate operand. The 256-bit operation is similar to the in-lane operation used by the 256-bit VPSHUFD instruction, which is illustrated in Figure 4-16. For 128-bit operation, only the low 128-bit lane is operative. Each 2-bit field in the immediate operand selects the contents of one word location in the low quadword of the destination operand. The binary encodings of the immediate operand fields select words (0, 1, 2 or 3) from the low quadword of the source operand to be copied to the destination operand. The high quadword of the source operand is copied to the high quadword of the destination operand, for each 128-bit lane.

Note that this instruction permits a word in the low quadword of the source operand to be copied to more than one word location in the low quadword of the destination operand.

In 64-bit mode and not encoded with VEX/EVEX, using a REX prefix in the form of REX.R permits this instruction to access additional registers (XMM8-XMM15).

128-bit Legacy SSE version: The destination operand is an XMM register. The source operand can be an XMM register or a 128-bit memory location. Bits (MAXVL-1:128) of the corresponding YMM destination register remain unchanged.

VEX.128 encoded version: The destination operand is an XMM register. The source operand can be an XMM register or a 128-bit memory location. Bits (MAXVL-1:128) of the destination YMM register are zeroed.

VEX.256 encoded version: The destination operand is an YMM register. The source operand can be an YMM register or a 256-bit memory location.

EVEX encoded version: The destination operand is a ZMM/YMM/XMM registers. The source operand can be a ZMM/YMM/XMM register, a 512/256/128-bit memory location. The destination is updated according to the writemask.

Note: In VEX encoded versions, VEX.vvvv is reserved and must be 1111b otherwise instructions will #UD.

Operation

PSHUFLW (128-bit Legacy SSE Version)
DEST[15:0] := (SRC >> (imm[1:0] *16))[15:0]
DEST[31:16] := (SRC >> (imm[3:2] * 16))[15:0]
DEST[47:32] := (SRC >> (imm[5:4] * 16))[15:0]
DEST[63:48] := (SRC >> (imm[7:6] * 16))[15:0]
DEST[127:64] := SRC[127:64]
DEST[MAXVL-1:128] (Unmodified)

VPSHUFLW (VEX.128 Encoded Version)
DEST[15:0] := (SRC1 >> (imm[1:0] *16))[15:0]
DEST[31:16] := (SRC1 >> (imm[3:2] * 16))[15:0]
DEST[47:32] := (SRC1 >> (imm[5:4] * 16))[15:0]
DEST[63:48] := (SRC1 >> (imm[7:6] * 16))[15:0]
DEST[127:64] := SRC[127:64]
DEST[MAXVL-1:128] := 0

VPSHUFLW (VEX.256 Encoded Version)
DEST[15:0] := (SRC1 >> (imm[1:0] *16))[15:0]
DEST[31:16] := (SRC1 >> (imm[3:2] * 16))[15:0]
DEST[47:32] := (SRC1 >> (imm[5:4] * 16))[15:0]
DEST[63:48] := (SRC1 >> (imm[7:6] * 16))[15:0]
DEST[127:64] := SRC1[127:64]
DEST[143:128] := (SRC1 >> (imm[1:0] *16))[143:128]
DEST[159:144] := (SRC1 >> (imm[3:2] * 16))[143:128]
DEST[175:160] := (SRC1 >> (imm[5:4] * 16))[143:128]
DEST[191:176] := (SRC1 >> (imm[7:6] * 16))[143:128]
DEST[255:192] := SRC1[255:192]
DEST[MAXVL-1:256] := 0

VPSHUFLW (EVEX.U1.512 Encoded Version)
(KL, VL) = (8, 128), (16, 256), (32, 512)
IF VL >= 128

    TMP_DEST[15:0] := (SRC1 >> (imm[1:0] *16))[15:0]
    TMP_DEST[31:16] := (SRC1 >> (imm[3:2] * 16))[15:0]
    TMP_DEST[47:32] := (SRC1 >> (imm[5:4] * 16))[15:0]
    TMP_DEST[63:48] := (SRC1 >> (imm[7:6] * 16))[15:0]
    TMP_DEST[127:64] := SRC1[127:64]
FI;
IF VL >= 256
    TMP_DEST[143:128] := (SRC1 >> (imm[1:0] *16))[143:128]
    TMP_DEST[159:144] := (SRC1 >> (imm[3:2] * 16))[143:128]
    TMP_DEST[175:160] := (SRC1 >> (imm[5:4] * 16))[143:128]
    TMP_DEST[191:176] := (SRC1 >> (imm[7:6] * 16))[143:128]
    TMP_DEST[255:192] := SRC1[255:192]
FI;
IF VL >= 512
    TMP_DEST[271:256] := (SRC1 >> (imm[1:0] *16))[271:256]
    TMP_DEST[287:272] := (SRC1 >> (imm[3:2] * 16))[271:256]
    TMP_DEST[303:288] := (SRC1 >> (imm[5:4] * 16))[271:256]
    TMP_DEST[319:304] := (SRC1 >> (imm[7:6] * 16))[271:256]
    TMP_DEST[383:320] := SRC1[383:320]


    TMP_DEST[399:384] := (SRC1 >> (imm[1:0] *16))[399:384]
    TMP_DEST[415:400] := (SRC1 >> (imm[3:2] * 16))[399:384]
    TMP_DEST[431:416] := (SRC1 >> (imm[5:4] * 16))[399:384]
    TMP_DEST[447:432] := (SRC1 >> (imm[7:6] * 16))[399:384]
    TMP_DEST[511:448] := SRC1[511:448]
FI;

FOR j := 0 TO KL-1

i := j * 16

IF k1[j] OR *no writemask*

     THEN DEST[i+15:i] := TMP_DEST[i+15:i];

     ELSE

             IF *merging-masking*            ; merging-masking

                 THEN *DEST[i+15:i] remains unchanged*

                 ELSE *zeroing-masking*      ; zeroing-masking

                    DEST[i+15:i] := 0

             FI

FI;

ENDFOR

DEST[MAXVL-1:VL] := 0

Intel C/C++ compiler intrinsics

VPSHUFLW __m512i _mm512_shufflelo_epi16(__m512i a, int n);
VPSHUFLW __m512i _mm512_mask_shufflelo_epi16(__m512i s, __mmask16 k, __m512i a, int n );
VPSHUFLW __m512i _mm512_maskz_shufflelo_epi16( __mmask16 k, __m512i a, int n );
VPSHUFLW __m256i _mm256_mask_shufflelo_epi16(__m256i s, __mmask8 k, __m256i a, int n );
VPSHUFLW __m256i _mm256_maskz_shufflelo_epi16( __mmask8 k, __m256i a, int n );
VPSHUFLW __m128i _mm_mask_shufflelo_epi16(__m128i s, __mmask8 k, __m128i a, int n );
VPSHUFLW __m128i _mm_maskz_shufflelo_epi16( __mmask8 k, __m128i a, int n );
(V)PSHUFLW:__m128i _mm_shufflelo_epi16(__m128i a, int n) VPSHUFLW:__m256i _mm256_shufflelo_epi16(__m256i a, const int n);

Flags affected

None.

SIMD Floating-Point Exceptions

None.

Other Exceptions

Non-EVEX-encoded instruction, see Table 2-21, "Type 4 Class Exception Conditions."

EVEX-encoded instruction, see Exceptions Type E4NF.nb in Table 2-52, "Type E4NF Class Exception Conditions."

Additionally:

#UD                    If VEX.vvvv != 1111B, or EVEX.vvvv != 1111B.

PSHUFLW

Encodings

Operand encoding

A

B

Measured cost

Description#

Operation#

Intel C/C++ compiler intrinsics#

Flags affected#

SIMD Floating-Point Exceptions#