# MULSD — Multiply Scalar Double Precision Floating-Point Value

Opcode/Instruction | Op / En | 64/32 bit Mode Support | CPUID Feature Flag | Description
--- | --- | --- | --- | ---
F2 0F 59 /r MULSD xmm1,xmm2/m64 | A | V/V | SSE2 | Multiply the low double precision floating-point value in xmm2/m64 by low double precision floating-point value in xmm1.
VEX.LIG.F2.0F.WIG 59 /r VMULSD xmm1,xmm2, xmm3/m64 | B | V/V | AVX | Multiply the low double precision floating-point value in xmm3/m64 by low double precision floating-point value in xmm2.
EVEX.LLIG.F2.0F.W1 59 /r VMULSD xmm1 {k1}{z}, xmm2, xmm3/m64 {er} | C | V/V | AVX512F | Multiply the low double precision floating-point value in xmm3/m64 by low double precision floating-point value in xmm2.

## 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 | Tuple1 Scalar | ModRM:reg (w) | EVEX.vvvv (r) | ModRM:r/m (r) | N/A

## Description ¶

Multiplies the low double precision floating-point value in the second source operand by the low double precision floating-point value in the first source operand, and stores the double precision floating-point result in the destination operand. The second source operand can be an XMM register or a 64-bit memory location. The first source operand and the destination operands are XMM registers.

128-bit Legacy SSE version: The first source operand and the destination operand are the same. Bits (MAXVL-1:64) of the corresponding destination register remain unchanged.

VEX.128 and EVEX encoded version: The quadword at bits 127:64 of the destination operand is copied from the same bits of the first source operand. Bits (MAXVL-1:128) of the destination register are zeroed.

EVEX encoded version: The low quadword element of the destination operand is updated according to the write-mask.

Software should ensure VMULSD is encoded with VEX.L=0. Encoding VMULSD with VEX.L=1 may encounter unpredictable behavior across different processor generations.

## Operation ¶

### VMULSD (EVEX Encoded Version) ¶

    IF (EVEX.b = 1) AND SRC2 *is a register*
        THEN
            SET_ROUNDING_MODE_FOR_THIS_INSTRUCTION(EVEX.RC);
        ELSE
            SET_ROUNDING_MODE_FOR_THIS_INSTRUCTION(MXCSR.RC);
    FI;
    IF k1[0] or *no writemask*
        THEN DEST[63:0] := SRC1[63:0] * SRC2[63:0]
        ELSE
            IF *merging-masking* ; merging-masking
                THEN *DEST[63:0] remains unchanged*
                ELSE ; zeroing-masking
                    THEN DEST[63:0] := 0
                FI
        FI;
    ENDFOR
    DEST[127:64] := SRC1[127:64]
    DEST[MAXVL-1:128] := 0

### VMULSD (VEX.128 Encoded Version) ¶

    DEST[63:0] := SRC1[63:0] * SRC2[63:0]
    DEST[127:64] := SRC1[127:64]
    DEST[MAXVL-1:128] := 0

### MULSD (128-bit Legacy SSE Version) ¶

    DEST[63:0] := DEST[63:0] * SRC[63:0]
    DEST[MAXVL-1:64] (Unmodified)

## Intel C/C++ Compiler Intrinsic Equivalent ¶

    VMULSD __m128d _mm_mask_mul_sd(__m128d s, __mmask8 k, __m128d a, __m128d b);

    VMULSD __m128d _mm_maskz_mul_sd( __mmask8 k, __m128d a, __m128d b);

    VMULSD __m128d _mm_mul_round_sd( __m128d a, __m128d b, int);

    VMULSD __m128d _mm_mask_mul_round_sd(__m128d s, __mmask8 k, __m128d a, __m128d b, int);

    VMULSD __m128d _mm_maskz_mul_round_sd( __mmask8 k, __m128d a, __m128d b, int);

    MULSD __m128d _mm_mul_sd (__m128d a, __m128d b)

## SIMD Floating-Point Exceptions ¶

Overflow, Underflow, Invalid, Precision, Denormal.

## Other Exceptions ¶

Non-EVEX-encoded instruction, see Table 2-20, “Type 3 Class Exception Conditions.”

EVEX-encoded instruction, see Table 2-47, “Type E3 Class Exception Conditions.”