pmulld

Packed Multiply Low Doubleword

PMULLD xmm1, xmm2/m128

Multiplies 32-bit integers, stores low 32-bit result.

Details

Multiplies four pairs of 32-bit signed integers in parallel, storing the low 32 bits of each product in the destination XMM register. This SSE4.1 instruction operates on 128-bit vectors and does not modify EFLAGS; overflow is silently discarded.

Pseudocode Operation

for (i = 0; i < 4; i++) {
  dest[i*32 : i*32+31] ← (src1[i*32 : i*32+31] * src2[i*32 : i*32+31]) & 0xFFFFFFFF
}

Example

PMULLD xmm1, xmm2/m128

Encoding

Binary Layout
66
+0
0F
+1
38
+2
40
+3
 
Format SSE4.1
Opcode 66 0F 38 40
Extension SSE4.1

Operands

  • dest
    128-bit XMM SIMD register
  • src
    128-bit XMM SIMD register or Memory operand

Reference (Intel® SDM)

Instruction Forms

Opcode Instruction Op/En 64/32-bit Mode CPUID Description
66 0F 38 40 /r PMULLD xmm1, xmm2/m128 A V/V SSE4_1 Multiply the packed dword signed integers in xmm1 and xmm2/m128 and store the low 32 bits of each product in xmm1.
VEX.128.66.0F38.WIG 40 /r VPMULLD xmm1, xmm2, xmm3/m128 B V/V AVX Multiply the packed dword signed integers in xmm2 and xmm3/m128 and store the low 32 bits of each product in xmm1.
VEX.256.66.0F38.WIG 40 /r VPMULLD ymm1, ymm2, ymm3/m256 B V/V AVX2 Multiply the packed dword signed integers in ymm2 and ymm3/m256 and store the low 32 bits of each product in ymm1.
EVEX.128.66.0F38.W0 40 /r VPMULLD xmm1 {k1}{z}, xmm2, xmm3/m128/m32bcst C V/V (AVX512VL AND AVX512F) OR AVX10.1 Multiply the packed dword signed integers in xmm2 and xmm3/m128/m32bcst and store the low 32 bits of each product in xmm1 under writemask k1.
EVEX.256.66.0F38.W0 40 /r VPMULLD ymm1 {k1}{z}, ymm2, ymm3/m256/m32bcst C V/V (AVX512VL AND AVX512F) OR AVX10.1 Multiply the packed dword signed integers in ymm2 and ymm3/m256/m32bcst and store the low 32 bits of each product in ymm1 under writemask k1.
EVEX.512.66.0F38.W0 40 /r VPMULLD zmm1 {k1}{z}, zmm2, zmm3/m512/m32bcst C V/V AVX512F OR AVX10.1 Multiply the packed dword signed integers in zmm2 and zmm3/m512/m32bcst and store the low 32 bits of each product in zmm1 under writemask k1.
EVEX.128.66.0F38.W1 40 /r VPMULLQ xmm1 {k1}{z}, xmm2, xmm3/m128/m64bcst C V/V (AVX512VL AND AVX512DQ) OR AVX10.1 Multiply the packed qword signed integers in xmm2 and xmm3/m128/m64bcst and store the low 64 bits of each product in xmm1 under writemask k1.
EVEX.256.66.0F38.W1 40 /r VPMULLQ ymm1 {k1}{z}, ymm2, ymm3/m256/m64bcst C V/V (AVX512VL AND AVX512DQ) OR AVX10.1 Multiply the packed qword signed integers in ymm2 and ymm3/m256/m64bcst and store the low 64 bits of each product in ymm1 under writemask k1.
EVEX.512.66.0F38.W1 40 /r VPMULLQ zmm1 {k1}{z}, zmm2, zmm3/m512/m64bcst C V/V AVX512DQ OR AVX10.1 Multiply the packed qword signed integers in zmm2 and zmm3/m512/m64bcst and store the low 64 bits of each product in zmm1 under 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) N/A N/A
B N/A ModRM:reg (w) VEX.vvvv (r) ModRM:r/m (r) N/A
C Full ModRM:reg (w) EVEX.vvvv (r) ModRM:r/m (r) N/A

Description

Performs a SIMD signed multiply of the packed signed dword/qword integers from each element of the first source operand with the corresponding element in the second source operand. The low 32/64 bits of each 64/128-bit intermediate results are stored to the destination operand. 128-bit Legacy SSE version: The first source and destination operands are XMM registers. The second source operand is an XMM register or a 128-bit memory location. Bits (MAXVL-1:128) of the corresponding ZMM destination register remain unchanged. VEX.128 encoded version: The first source and destination operands are XMM registers. The second source operand is an XMM register or a 128-bit memory location. Bits (MAXVL-1:128) of the corresponding ZMM register are zeroed. VEX.256 encoded version: The first source operand is a YMM register; The second source operand is a YMM register or 256-bit memory location. Bits (MAXVL-1:256) of the corresponding destination ZMM register are zeroed. PMULLD/PMULLQ—Multiply Packed Integers and Store Low Result Vol. 2B 4-387 EVEX encoded versions: The first source operand is a ZMM/YMM/XMM register. The second source operand is a ZMM/YMM/XMM register, a 512/256/128-bit memory location or a 512/256/128-bit vector broadcasted from a 32/64-bit memory location. The destination operand is conditionally updated based on writemask k1.

Operation

VPMULLQ (EVEX Encoded Versions)
(KL, VL) = (2, 128), (4, 256), (8, 512)
FOR j := 0 TO KL-1
i := j * 64
IF k1[j] OR *no writemask* THEN
IF (EVEX.b == 1) AND (SRC2 *is memory*)
THEN Temp[127:0] := SRC1[i+63:i] * SRC2[63:0]
ELSE Temp[127:0] := SRC1[i+63:i] * SRC2[i+63:i]
FI;
DEST[i+63:i] := Temp[63:0]
ELSE
IF *merging-masking*                                 ; merging-masking
THEN *DEST[i+63:i] remains unchanged*
ELSE                                                         ; zeroing-masking
DEST[i+63:i] := 0
FI
FI;
ENDFOR
DEST[MAXVL-1:VL] := 0

VPMULLD (EVEX Encoded Versions)
(KL, VL) = (4, 128), (8, 256), (16, 512)
FOR j := 0 TO KL-1
i := j * 32
IF k1[j] OR *no writemask* THEN
IF (EVEX.b = 1) AND (SRC2 *is memory*)
THEN Temp[63:0] := SRC1[i+31:i] * SRC2[31:0]
ELSE Temp[63:0] := SRC1[i+31:i] * SRC2[i+31:i]
FI;
DEST[i+31:i] := Temp[31:0]
ELSE
IF *merging-masking*                                 ; merging-masking
*DEST[i+31:i] remains unchanged*
ELSE                                                         ; zeroing-masking
DEST[i+31:i] := 0
FI
FI;
ENDFOR
DEST[MAXVL-1:VL] := 0





PMULLD/PMULLQ—Multiply Packed Integers and Store Low Result                                                                             Vol. 2B 4-388
VPMULLD (VEX.256 Encoded Version)
Temp0[63:0] := SRC1[31:0] * SRC2[31:0]
Temp1[63:0] := SRC1[63:32] * SRC2[63:32]
Temp2[63:0] := SRC1[95:64] * SRC2[95:64]
Temp3[63:0] := SRC1[127:96] * SRC2[127:96]
Temp4[63:0] := SRC1[159:128] * SRC2[159:128]
Temp5[63:0] := SRC1[191:160] * SRC2[191:160]
Temp6[63:0] := SRC1[223:192] * SRC2[223:192]
Temp7[63:0] := SRC1[255:224] * SRC2[255:224]

DEST[31:0] := Temp0[31:0]
DEST[63:32] := Temp1[31:0]
DEST[95:64] := Temp2[31:0]
DEST[127:96] := Temp3[31:0]
DEST[159:128] := Temp4[31:0]
DEST[191:160] := Temp5[31:0]
DEST[223:192] := Temp6[31:0]
DEST[255:224] := Temp7[31:0]
DEST[MAXVL-1:256] := 0

VPMULLD (VEX.128 Encoded Version)
Temp0[63:0] := SRC1[31:0] * SRC2[31:0]
Temp1[63:0] := SRC1[63:32] * SRC2[63:32]
Temp2[63:0] := SRC1[95:64] * SRC2[95:64]
Temp3[63:0] := SRC1[127:96] * SRC2[127:96]
DEST[31:0] := Temp0[31:0]
DEST[63:32] := Temp1[31:0]
DEST[95:64] := Temp2[31:0]
DEST[127:96] := Temp3[31:0]
DEST[MAXVL-1:128] := 0

PMULLD (128-bit Legacy SSE Version)
Temp0[63:0] := DEST[31:0] * SRC[31:0]
Temp1[63:0] := DEST[63:32] * SRC[63:32]
Temp2[63:0] := DEST[95:64] * SRC[95:64]
Temp3[63:0] := DEST[127:96] * SRC[127:96]
DEST[31:0] := Temp0[31:0]
DEST[63:32] := Temp1[31:0]
DEST[95:64] := Temp2[31:0]
DEST[127:96] := Temp3[31:0]
DEST[MAXVL-1:128] (Unmodified)





PMULLD/PMULLQ—Multiply Packed Integers and Store Low Result                                                                             Vol. 2B 4-389

Intel C/C++ Compiler Intrinsic Equivalent

VPMULLD __m512i _mm512_mullo_epi32(__m512i a, __m512i b);
VPMULLD __m512i _mm512_mask_mullo_epi32(__m512i s, __mmask16 k, __m512i a, __m512i b);
VPMULLD __m512i _mm512_maskz_mullo_epi32( __mmask16 k, __m512i a, __m512i b);
VPMULLD __m256i _mm256_mask_mullo_epi32(__m256i s, __mmask8 k, __m256i a, __m256i b);
VPMULLD __m256i _mm256_maskz_mullo_epi32( __mmask8 k, __m256i a, __m256i b);
VPMULLD __m128i _mm_mask_mullo_epi32(__m128i s, __mmask8 k, __m128i a, __m128i b);
VPMULLD __m128i _mm_maskz_mullo_epi32( __mmask8 k, __m128i a, __m128i b);
VPMULLD __m256i _mm256_mullo_epi32(__m256i a, __m256i b);
PMULLD __m128i _mm_mullo_epi32(__m128i a, __m128i b);
VPMULLQ __m512i _mm512_mullo_epi64(__m512i a, __m512i b);
VPMULLQ __m512i _mm512_mask_mullo_epi64(__m512i s, __mmask8 k, __m512i a, __m512i b);
VPMULLQ __m512i _mm512_maskz_mullo_epi64( __mmask8 k, __m512i a, __m512i b);
VPMULLQ __m256i _mm256_mullo_epi64(__m256i a, __m256i b);
VPMULLQ __m256i _mm256_mask_mullo_epi64(__m256i s, __mmask8 k, __m256i a, __m256i b);
VPMULLQ __m256i _mm256_maskz_mullo_epi64( __mmask8 k, __m256i a, __m256i b);
VPMULLQ __m128i _mm_mullo_epi64(__m128i a, __m128i b);
VPMULLQ __m128i _mm_mask_mullo_epi64(__m128i s, __mmask8 k, __m128i a, __m128i b);
VPMULLQ __m128i _mm_maskz_mullo_epi64( __mmask8 k, __m128i a, __m128i b);

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 2-51, “Type E4 Class Exception Conditions.” PMULLD/PMULLQ—Multiply Packed Integers and Store Low Result Vol. 2B 4-390