shufpd

Shuffle Packed Double-Precision

SHUFPD xmm1, xmm2/m128, imm8

Shuffles 64-bit doubles between two XMM registers.

Details

Shuffles two 64-bit double-precision floating-point values from the destination XMM register and source XMM/memory operand according to a 2-bit control value in the immediate byte, placing the result in the destination. The low bit selects element 0 of the result (from dest or src), the high bit selects element 1. No arithmetic flags are affected. Requires SSE2 or later.

Pseudocode Operation

dest[63:0] ← imm8[0] ? src[63:0] : dest[63:0]
dest[127:64] ← imm8[1] ? src[127:64] : dest[127:64]

Example

SHUFPD xmm1, xmm2/m128, 3

Encoding

Binary Layout
66
+0
0F
+1
C6
+2
 
Format SSE2
Opcode 66 0F C6
Extension SSE2

Operands

  • dest
    128-bit XMM SIMD register
  • src1
    128-bit XMM SIMD register or Memory operand
  • src2
    8-bit signed immediate

Reference (Intel® SDM)

Instruction Forms

Opcode Instruction Op/En 64/32-bit Mode CPUID Description
66 0F C6 /r ib SHUFPD xmm1, xmm2/m128, imm8 A V/V SSE2 Shuffle two pairs of double precision floating-point values from xmm1 and xmm2/m128 using imm8 to select from each pair, interleaved result is stored in xmm1.
VEX.128.66.0F.WIG C6 /r ib VSHUFPD xmm1, xmm2, xmm3/m128, imm8 B V/V AVX Shuffle two pairs of double precision floating-point values from xmm2 and xmm3/m128 using imm8 to select from each pair, interleaved result is stored in xmm1.
VEX.256.66.0F.WIG C6 /r ib VSHUFPD ymm1, ymm2, ymm3/m256, imm8 B V/V AVX Shuffle four pairs of double precision floating-point values from ymm2 and ymm3/m256 using imm8 to select from each pair, interleaved result is stored in xmm1.
EVEX.128.66.0F.W1 C6 /r ib VSHUFPD xmm1{k1}{z}, xmm2, xmm3/m128/m64bcst, imm8 C V/V (AVX512VL AND AVX512F) OR AVX10.1 Shuffle two pairs of double precision floating-point values from xmm2 and xmm3/m128/m64bcst using imm8 to select from each pair. store interleaved results in xmm1 subject to writemask k1.
EVEX.256.66.0F.W1 C6 /r ib VSHUFPD ymm1{k1}{z}, ymm2, ymm3/m256/m64bcst, imm8 C V/V (AVX512VL AND AVX512F) OR AVX10.1 Shuffle four pairs of double precision floating-point values from ymm2 and ymm3/m256/m64bcst using imm8 to select from each pair. store interleaved results in ymm1 subject to writemask k1.
EVEX.512.66.0F.W1 C6 /r ib VSHUFPD zmm1{k1}{z}, zmm2, zmm3/m512/m64bcst, imm8 C V/V AVX512F OR AVX10.1 Shuffle eight pairs of double precision floating-point values from zmm2 and zmm3/m512/m64bcst using imm8 to select from each pair. store interleaved results in zmm1 subject to writemask k1.

Instruction Operand Encoding

Op/En Tuple Type Operand 1 Operand 2 Operand 3 Operand 4
A N/A ModRM:reg (r, w) ModRM:r/m (r) imm8 N/A
B N/A ModRM:reg (w) VEX.vvvv (r) ModRM:r/m (r) imm8
C Full ModRM:reg (w) EVEX.vvvv (r) ModRM:r/m (r) imm8

Description

Selects a double precision floating-point value of an input pair using a bit control and move to a designated element of the destination operand. The low-to-high order of double precision element of the destination operand is interleaved between the first source operand and the second source operand at the granularity of input pair of 128 bits. Each bit in the imm8 byte, starting from bit 0, is the select control of the corresponding element of the destination to received the shuffled result of an input pair. EVEX encoded versions: The first source operand is a ZMM/YMM/XMM register. The second source operand can be a ZMM/YMM/XMM register, a 512/256/128-bit memory location or a 512/256/128-bit vector broadcasted from a 64-bit memory location The destination operand is a ZMM/YMM/XMM register updated according to the writemask. The select controls are the lower 8/4/2 bits of the imm8 byte. VEX.256 encoded version: The first source operand is a YMM register. The second source operand can be a YMM register or a 256-bit memory location. The destination operand is a YMM register. The select controls are the bit 3:0 of the imm8 byte, imm8[7:4) are ignored. VEX.128 encoded version: The first source operand is a XMM register. The second source operand can be a XMM register or a 128-bit memory location. The destination operand is a XMM register. The upper bits (MAXVL-1:128) of SHUFPD—Packed Interleave Shuffle of Pairs of Double Precision Floating-Point Values Vol. 2B 4-645 the corresponding ZMM register destination are zeroed. The select controls are the bit 1:0 of the imm8 byte, imm8[7:2) are ignored. 128-bit Legacy SSE version: The second source can be an XMM register or an 128-bit memory location. The destination operand and the first source operand is the same and is an XMM register. The upper bits (MAXVL-1:128) of the corresponding ZMM register destination are unmodified. The select controls are the bit 1:0 of the imm8 byte, imm8[7:2) are ignored. SRC1 X3 X2 X1 X0 SRC2 Y3 Y2 Y1 Y0 DEST Y2 or Y3 X2 or X3 Y0 or Y1 X0 or X1 Figure 4-25. 256-bit VSHUFPD Operation of Four Pairs of Double Precision Floating-Point Values

Operation

VSHUFPD (EVEX Encoded Versions When SRC2 is a Vector Register)
(KL, VL) = (2, 128), (4, 256), (8, 512)
IF IMM0[0] = 0
THEN TMP_DEST[63:0] := SRC1[63:0]
ELSE TMP_DEST[63:0] := SRC1[127:64] FI;
IF IMM0[1] = 0
THEN TMP_DEST[127:64] := SRC2[63:0]
ELSE TMP_DEST[127:64] := SRC2[127:64] FI;
IF VL >= 256
IF IMM0[2] = 0
THEN TMP_DEST[191:128] := SRC1[191:128]
ELSE TMP_DEST[191:128] := SRC1[255:192] FI;
IF IMM0[3] = 0
THEN TMP_DEST[255:192] := SRC2[191:128]
ELSE TMP_DEST[255:192] := SRC2[255:192] FI;
FI;
IF VL >= 512
IF IMM0[4] = 0
THEN TMP_DEST[319:256] := SRC1[319:256]
ELSE TMP_DEST[319:256] := SRC1[383:320] FI;
IF IMM0[5] = 0
THEN TMP_DEST[383:320] := SRC2[319:256]
ELSE TMP_DEST[383:320] := SRC2[383:320] FI;
IF IMM0[6] = 0
THEN TMP_DEST[447:384] := SRC1[447:384]
ELSE TMP_DEST[447:384] := SRC1[511:448] FI;
IF IMM0[7] = 0
THEN TMP_DEST[511:448] := SRC2[447:384]
ELSE TMP_DEST[511:448] := SRC2[511:448] FI;
FI;
FOR j := 0 TO KL-1
i := j * 64



SHUFPD—Packed Interleave Shuffle of Pairs of Double Precision Floating-Point Values                                                       Vol. 2B 4-646
IF k1[j] OR *no writemask*
THEN DEST[i+63:i] := TMP_DEST[i+63:i]
ELSE
IF *merging-masking*                                 ; merging-masking
THEN *DEST[i+63:i] remains unchanged*
ELSE *zeroing-masking*                            ; zeroing-masking
DEST[i+63:i] := 0
FI
FI;
ENDFOR
DEST[MAXVL-1:VL] := 0

VSHUFPD (EVEX Encoded Versions When SRC2 is Memory)
(KL, VL) = (2, 128), (4, 256), (8, 512)

FOR j := 0 TO KL-1
i := j * 64
IF (EVEX.b = 1)
THEN TMP_SRC2[i+63:i] := SRC2[63:0]
ELSE TMP_SRC2[i+63:i] := SRC2[i+63:i]
FI;
ENDFOR;
IF IMM0[0] = 0
THEN TMP_DEST[63:0] := SRC1[63:0]
ELSE TMP_DEST[63:0] := SRC1[127:64] FI;
IF IMM0[1] = 0
THEN TMP_DEST[127:64] := TMP_SRC2[63:0]
ELSE TMP_DEST[127:64] := TMP_SRC2[127:64] FI;
IF VL >= 256
IF IMM0[2] = 0
THEN TMP_DEST[191:128] := SRC1[191:128]
ELSE TMP_DEST[191:128] := SRC1[255:192] FI;
IF IMM0[3] = 0
THEN TMP_DEST[255:192] := TMP_SRC2[191:128]
ELSE TMP_DEST[255:192] := TMP_SRC2[255:192] FI;
FI;
IF VL >= 512
IF IMM0[4] = 0
THEN TMP_DEST[319:256] := SRC1[319:256]
ELSE TMP_DEST[319:256] := SRC1[383:320] FI;
IF IMM0[5] = 0
THEN TMP_DEST[383:320] := TMP_SRC2[319:256]
ELSE TMP_DEST[383:320] := TMP_SRC2[383:320] FI;
IF IMM0[6] = 0
THEN TMP_DEST[447:384] := SRC1[447:384]
ELSE TMP_DEST[447:384] := SRC1[511:448] FI;
IF IMM0[7] = 0
THEN TMP_DEST[511:448] := TMP_SRC2[447:384]
ELSE TMP_DEST[511:448] := TMP_SRC2[511:448] FI;
FI;
FOR j := 0 TO KL-1
i := j * 64
IF k1[j] OR *no writemask*
THEN DEST[i+63:i] := TMP_DEST[i+63:i]


SHUFPD—Packed Interleave Shuffle of Pairs of Double Precision Floating-Point Values                                                       Vol. 2B 4-647
ELSE
IF *merging-masking*                                 ; merging-masking
THEN *DEST[i+63:i] remains unchanged*
ELSE *zeroing-masking*                            ; zeroing-masking
DEST[i+63:i] := 0
FI
FI;
ENDFOR
DEST[MAXVL-1:VL] := 0

VSHUFPD (VEX.256 Encoded Version)
IF IMM0[0] = 0
THEN DEST[63:0] := SRC1[63:0]
ELSE DEST[63:0] := SRC1[127:64] FI;
IF IMM0[1] = 0
THEN DEST[127:64] := SRC2[63:0]
ELSE DEST[127:64] := SRC2[127:64] FI;
IF IMM0[2] = 0
THEN DEST[191:128] := SRC1[191:128]
ELSE DEST[191:128] := SRC1[255:192] FI;
IF IMM0[3] = 0
THEN DEST[255:192] := SRC2[191:128]
ELSE DEST[255:192] := SRC2[255:192] FI;
DEST[MAXVL-1:256] (Unmodified)

VSHUFPD (VEX.128 Encoded Version)
IF IMM0[0] = 0
THEN DEST[63:0] := SRC1[63:0]
ELSE DEST[63:0] := SRC1[127:64] FI;
IF IMM0[1] = 0
THEN DEST[127:64] := SRC2[63:0]
ELSE DEST[127:64] := SRC2[127:64] FI;
DEST[MAXVL-1:128] := 0

VSHUFPD (128-bit Legacy SSE Version)
IF IMM0[0] = 0
THEN DEST[63:0] := SRC1[63:0]
ELSE DEST[63:0] := SRC1[127:64] FI;
IF IMM0[1] = 0
THEN DEST[127:64] := SRC2[63:0]
ELSE DEST[127:64] := SRC2[127:64] FI;
DEST[MAXVL-1:128] (Unmodified)





SHUFPD—Packed Interleave Shuffle of Pairs of Double Precision Floating-Point Values                                                       Vol. 2B 4-648

Intel C/C++ Compiler Intrinsic Equivalent

VSHUFPD __m512d _mm512_shuffle_pd(__m512d a, __m512d b, int imm);
VSHUFPD __m512d _mm512_mask_shuffle_pd(__m512d s, __mmask8 k, __m512d a, __m512d b, int imm);
VSHUFPD __m512d _mm512_maskz_shuffle_pd( __mmask8 k, __m512d a, __m512d b, int imm);
VSHUFPD __m256d _mm256_shuffle_pd (__m256d a, __m256d b, const int select);
VSHUFPD __m256d _mm256_mask_shuffle_pd(__m256d s, __mmask8 k, __m256d a, __m256d b, int imm);
VSHUFPD __m256d _mm256_maskz_shuffle_pd( __mmask8 k, __m256d a, __m256d b, int imm);
SHUFPD __m128d _mm_shuffle_pd (__m128d a, __m128d b, const int select);
VSHUFPD __m128d _mm_mask_shuffle_pd(__m128d s, __mmask8 k, __m128d a, __m128d b, int imm);
VSHUFPD __m128d _mm_maskz_shuffle_pd( __mmask8 k, __m128d a, __m128d b, int imm);

Exceptions

SIMD Floating-Point Exceptions

None.

Other Exceptions

Non-EVEX-encoded instruction, see Table 2-21, “Type 4 Class Exception Conditions.” EVEX-encoded instruction, see Table 2-52, “Type E4NF Class Exception Conditions.” SHUFPD—Packed Interleave Shuffle of Pairs of Double Precision Floating-Point Values Vol. 2B 4-649