subpd

Subtract Packed Double-Precision

SUBPD xmm, xmm/m128

Subtracts two 64-bit doubles.

Details

Subtracts two 64-bit double-precision floating-point values in the source operand from the two 64-bit double-precision values in the destination XMM register, storing both results in the destination. Operates on packed values in parallel and respects IEEE 754 rounding modes controlled by MXCSR.

Pseudocode Operation

dest[63:0] ← dest[63:0] - src[63:0];
dest[127:64] ← dest[127:64] - src[127:64];

Example

SUBPD xmm0, xmm1

Encoding

Binary Layout
66
+0
0F
+1
5C
+2
 
Format SSE2
Opcode 66 0F 5C
Extension SSE2

Operands

  • dest
    128-bit SSE/AVX register (XMM)
  • src
    128-bit XMM register or 128-bit memory

Reference (Intel® SDM)

Instruction Forms

Opcode Instruction Op/En 64/32-bit Mode CPUID Description
66 0F 5C /r SUBPD xmm1, xmm2/m128 A V/V SSE2 Subtract packed double precision floating-point values in xmm2/mem from xmm1 and store result in xmm1.
VEX.128.66.0F.WIG 5C /r VSUBPD xmm1,xmm2, xmm3/m128 B V/V AVX Subtract packed double precision floating-point values in xmm3/mem from xmm2 and store result in xmm1.
VEX.256.66.0F.WIG 5C /r VSUBPD ymm1, ymm2, ymm3/m256 B V/V AVX Subtract packed double precision floating-point values in ymm3/mem from ymm2 and store result in ymm1.
EVEX.128.66.0F.W1 5C /r VSUBPD xmm1 {k1}{z}, xmm2, xmm3/m128/m64bcst C V/V (AVX512VL AND AVX512F) OR AVX10.1 Subtract packed double precision floating-point values from xmm3/m128/m64bcst to xmm2 and store result in xmm1 with writemask k1.
EVEX.256.66.0F.W1 5C /r VSUBPD ymm1 {k1}{z}, ymm2, ymm3/m256/m64bcst C V/V (AVX512VL AND AVX512F) OR AVX10.1 Subtract packed double precision floating-point values from ymm3/m256/m64bcst to ymm2 and store result in ymm1 with writemask k1.
EVEX.512.66.0F.W1 5C /r VSUBPD zmm1 {k1}{z}, zmm2, zmm3/m512/m64bcst{er} C V/V AVX512F OR AVX10.1 Subtract packed double precision floating-point values from zmm3/m512/m64bcst to zmm2 and store result in zmm1 with 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 subtract of the two, four or eight packed double precision floating-point values of the second Source operand from the first Source operand, and stores the packed double precision floating-point results in the destination operand. VEX.128 and EVEX.128 encoded versions: The second source operand is an XMM register or an 128-bit memory location. The first source operand and destination operands are XMM registers. Bits (MAXVL-1:128) of the corresponding destination register are zeroed. VEX.256 and EVEX.256 encoded versions: The second source operand is an YMM register or an 256-bit memory location. The first source operand and destination operands are YMM registers. Bits (MAXVL-1:256) of the corresponding destination register are zeroed. EVEX.512 encoded version: The second source operand is a ZMM register, a 512-bit memory location or a 512-bit vector broadcasted from a 64-bit memory location. The first source operand and destination operands are ZMM registers. The destination operand is conditionally updated according to the writemask. 128-bit Legacy SSE version: The second source can be an XMM register or an 128-bit memory location. The destination is not distinct from the first source XMM register and the upper Bits (MAXVL-1:128) of the corresponding register destination are unmodified. SUBPD—Subtract Packed Double Precision Floating-Point Values Vol. 2B 4-686

Operation

VSUBPD (EVEX Encoded Versions When SRC2 Operand is a Vector Register)
(KL, VL) = (2, 128), (4, 256), (8, 512)
IF (VL = 512) AND (EVEX.b = 1)
THEN
SET_ROUNDING_MODE_FOR_THIS_INSTRUCTION(EVEX.RC);
ELSE
SET_ROUNDING_MODE_FOR_THIS_INSTRUCTION(MXCSR.RC);
FI;

FOR j := 0 TO KL-1
i := j * 64
IF k1[j] OR *no writemask*
THEN DEST[i+63:i] := SRC1[i+63:i] - SRC2[i+63:i]
ELSE
IF *merging-masking*                                 ; merging-masking
THEN *DEST[63:0] remains unchanged*
ELSE                                                         ; zeroing-masking
DEST[63:0] := 0
FI;
FI;
ENDFOR
DEST[MAXVL-1:VL] := 0

VSUBPD (EVEX Encoded Versions When SRC2 Operand is a Memory Source)
(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)
THEN    DEST[i+63:i] := SRC1[i+63:i] - SRC2[63:0];
ELSE     EST[i+63:i] := SRC1[i+63:i] - SRC2[i+63:i];
FI;
ELSE
IF *merging-masking*                                 ; merging-masking
THEN *DEST[63:0] remains unchanged*
ELSE                                                         ; zeroing-masking
DEST[63:0] := 0
FI;
FI;
ENDFOR
DEST[MAXVL-1:VL] := 0

VSUBPD (VEX.256 Encoded Version)
DEST[63:0] := SRC1[63:0] - SRC2[63:0]
DEST[127:64] := SRC1[127:64] - SRC2[127:64]
DEST[191:128] := SRC1[191:128] - SRC2[191:128]
DEST[255:192] := SRC1[255:192] - SRC2[255:192]
DEST[MAXVL-1:256] := 0





SUBPD—Subtract Packed Double Precision Floating-Point Values                                                                               Vol. 2B 4-687
VSUBPD (VEX.128 Encoded Version)
DEST[63:0] := SRC1[63:0] - SRC2[63:0]
DEST[127:64] := SRC1[127:64] - SRC2[127:64]
DEST[MAXVL-1:128] := 0

SUBPD (128-bit Legacy SSE Version)
DEST[63:0] := DEST[63:0] - SRC[63:0]
DEST[127:64] := DEST[127:64] - SRC[127:64]
DEST[MAXVL-1:128] (Unmodified)

Intel C/C++ Compiler Intrinsic Equivalent

VSUBPD __m512d _mm512_sub_pd (__m512d a, __m512d b);
VSUBPD __m512d _mm512_mask_sub_pd (__m512d s, __mmask8 k, __m512d a, __m512d b);
VSUBPD __m512d _mm512_maskz_sub_pd (__mmask8 k, __m512d a, __m512d b);
VSUBPD __m512d _mm512_sub_round_pd (__m512d a, __m512d b, int);
VSUBPD __m512d _mm512_mask_sub_round_pd (__m512d s, __mmask8 k, __m512d a, __m512d b, int);
VSUBPD __m512d _mm512_maskz_sub_round_pd (__mmask8 k, __m512d a, __m512d b, int);
VSUBPD __m256d _mm256_sub_pd (__m256d a, __m256d b);
VSUBPD __m256d _mm256_mask_sub_pd (__m256d s, __mmask8 k, __m256d a, __m256d b);
VSUBPD __m256d _mm256_maskz_sub_pd (__mmask8 k, __m256d a, __m256d b);
SUBPD __m128d _mm_sub_pd (__m128d a, __m128d b);
VSUBPD __m128d _mm_mask_sub_pd (__m128d s, __mmask8 k, __m128d a, __m128d b);
VSUBPD __m128d _mm_maskz_sub_pd (__mmask8 k, __m128d a, __m128d b);

Exceptions

SIMD Floating-Point Exceptions

Overflow, Underflow, Invalid, Precision, Denormal.

Other Exceptions

VEX-encoded instructions, see Table 2-19, “Type 2 Class Exception Conditions.” EVEX-encoded instructions, see Table 2-48, “Type E2 Class Exception Conditions.” SUBPD—Subtract Packed Double Precision Floating-Point Values Vol. 2B 4-688