divpd

Divide Packed Double-Precision

DIVPD xmm, xmm/m128

Divides two 64-bit doubles.

Details

Divides two 64-bit double-precision floating-point values in the destination XMM register by the two 64-bit double-precision values in the source operand, storing both quotients in the destination. Operates on packed values in parallel and respects IEEE 754 rounding modes controlled by MXCSR; division by zero produces infinity or NaN according to IEEE 754 rules.

Pseudocode Operation

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

Example

DIVPD xmm0, xmm1

Encoding

Binary Layout
66
+0
0F
+1
5E
+2
 
Format SSE2
Opcode 66 0F 5E
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 5E /r DIVPD xmm1, xmm2/m128 A V/V SSE2 Divide packed double precision floating-point values in xmm1 by packed double precision floating-point values in xmm2/mem.
VEX.128.66.0F.WIG 5E /r VDIVPD xmm1, xmm2, xmm3/m128 B V/V AVX Divide packed double precision floating-point values in xmm2 by packed double precision floating-point values in xmm3/mem.
VEX.256.66.0F.WIG 5E /r VDIVPD ymm1, ymm2, ymm3/m256 B V/V AVX Divide packed double precision floating-point values in ymm2 by packed double precision floating-point values in ymm3/mem.
EVEX.128.66.0F.W1 5E /r VDIVPD xmm1 {k1}{z}, xmm2, xmm3/m128/m64bcst C V/V (AVX512VL AND AVX512F) OR AVX10.1 Divide packed double precision floating-point values in xmm2 by packed double precision floating-point values in xmm3/m128/m64bcst and write results to xmm1 subject to writemask k1.
EVEX.256.66.0F.W1 5E /r VDIVPD ymm1 {k1}{z}, ymm2, ymm3/m256/m64bcst C V/V (AVX512VL AND AVX512F) OR AVX10.1 Divide packed double precision floating-point values in ymm2 by packed double precision floating-point values in ymm3/m256/m64bcst and write results to ymm1 subject to writemask k1.
EVEX.512.66.0F.W1 5E /r VDIVPD zmm1 {k1}{z}, zmm2, zmm3/m512/m64bcst{er} C V/V AVX512F OR AVX10.1 Divide packed double precision floating-point values in zmm2 by packed double precision floating-point values in zmm3/m512/m64bcst and write results to 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) 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 divide of the double precision floating-point values in the first source operand by the floatingpoint values in the second source operand (the third operand). Results are written to the destination operand (the first operand). EVEX encoded versions: The first source operand (the second 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 conditionally updated with writemask k1. VEX.256 encoded version: The first source operand (the second 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 upper bits (MAXVL-1:256) of the corresponding destination are zeroed. VEX.128 encoded version: The first source operand (the second 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 the corresponding destination are zeroed. 128-bit Legacy SSE version: The second source operand (the second operand) can be an XMM register or an 128bit memory location. The destination is the same as the first source operand. The upper bits (MAXVL-1:128) of the corresponding destination are unmodified. DIVPD—Divide Packed Double Precision Floating-Point Values Vol. 2A 3-267

Operation

VDIVPD (EVEX Encoded Versions)
(KL, VL) = (2, 128), (4, 256), (8, 512)
IF (VL = 512) AND (EVEX.b = 1) AND SRC2 *is a register*
THEN
SET_ROUNDING_MODE_FOR_THIS_INSTRUCTION(EVEX.RC);  ; refer to Table 15-4 in the Intel® 64 and IA-32 Architectures
Software Developer’s Manual, Volume 1
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
IF (EVEX.b = 1) AND (SRC2 *is memory*)
THEN
DEST[i+63:i] := SRC1[i+63:i] / SRC2[63:0]
ELSE
DEST[i+63:i] := SRC1[i+63:i] / SRC2[i+63:i]
FI;
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

VDIVPD (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;

VDIVPD (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;

DIVPD (128-bit Legacy SSE Version)
DEST[63:0] := SRC1[63:0] / SRC2[63:0]
DEST[127:64] := SRC1[127:64] / SRC2[127:64]
DEST[MAXVL-1:128] (Unmodified)





DIVPD—Divide Packed Double Precision Floating-Point Values                                                                                  Vol. 2A 3-268

Intel C/C++ Compiler Intrinsic Equivalent

VDIVPD __m512d _mm512_div_pd( __m512d a, __m512d b);
VDIVPD __m512d _mm512_mask_div_pd(__m512d s, __mmask8 k, __m512d a, __m512d b);
VDIVPD __m512d _mm512_maskz_div_pd( __mmask8 k, __m512d a, __m512d b);
VDIVPD __m256d _mm256_mask_div_pd(__m256d s, __mmask8 k, __m256d a, __m256d b);
VDIVPD __m256d _mm256_maskz_div_pd( __mmask8 k, __m256d a, __m256d b);
VDIVPD __m128d _mm_mask_div_pd(__m128d s, __mmask8 k, __m128d a, __m128d b);
VDIVPD __m128d _mm_maskz_div_pd( __mmask8 k, __m128d a, __m128d b);
VDIVPD __m512d _mm512_div_round_pd( __m512d a, __m512d b, int);
VDIVPD __m512d _mm512_mask_div_round_pd(__m512d s, __mmask8 k, __m512d a, __m512d b, int);
VDIVPD __m512d _mm512_maskz_div_round_pd( __mmask8 k, __m512d a, __m512d b, int);
VDIVPD __m256d _mm256_div_pd (__m256d a, __m256d b);
DIVPD __m128d _mm_div_pd (__m128d a, __m128d b);

Exceptions

SIMD Floating-Point Exceptions

Overflow, Underflow, Invalid, Divide-by-Zero, 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.” DIVPD—Divide Packed Double Precision Floating-Point Values Vol. 2A 3-269