ADDSD—Add Scalar Double-Precision Floating-Point Values

Opcode/Instruction	Op /En	64/32 bit Mode Support	CPUID Feature Flag	Description
F2 0F 58 /r ADDSD xmm1, xmm2/m64	RM	V/V	SSE2	Add the low double-precision floating-point value from xmm2/mem to xmm1 and store the result in xmm1.
VEX.NDS.128.F2.0F.WIG 58 /r VADDSD xmm1, xmm2, xmm3/m64	RVM	V/V	AVX	Add the low double-precision floating-point value from xmm3/mem to xmm2 and store the result in xmm1.
EVEX.NDS.LIG.F2.0F.W1 58 /r VADDSD xmm1 {k1}{z}, xmm2, xmm3/m64{er}	T1S	V/V	AVX512F	Add the low double-precision floating-point value from xmm3/m64 to xmm2 and store the result in xmm1 with writemask k1.

Instruction Operand Encoding

Op/En	Operand 1	Operand 2	Operand 3	Operand 4
RM	ModRM:reg (r, w)	ModRM:r/m (r)	NA	NA
RVM	ModRM:reg (w)	VEX.vvvv	ModRM:r/m (r)	NA
T1S-RVM	ModRM:reg (w)	EVEX.vvvv	ModRM:r/m (r)	NA

Description

Adds the low double-precision floating-point values from the second source operand and 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 and destination operands are XMM registers.

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

EVEX and VEX.128 encoded version: The first source operand is encoded by EVEX.vvvv/VEX.vvvv. Bits (127:64) of the XMM register destination are copied from corresponding bits in the first source operand. Bits (MAX_VL-1:128) of the destination register are zeroed.

EVEX version: The low quadword element of the destination is updated according to the writemask.

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

Operation

VADDSD (EVEX encoded version)

IF (EVEX.b = 1) AND SRC2 *is a register*
    THEN
    SET_RM(EVEX.RC);
    ELSE
    SET_RM(MXCSR.RM);
FI;
IF k1[0] or *no writemask*
    THEN
    DEST[63:0] (cid:197) 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] (cid:197) 0
    FI;
FI;
DEST[127:64] (cid:197) SRC1[127:64]
DEST[MAX_VL-1:128] (cid:197) 0

VADDSD (VEX.128 encoded version)

DEST[63:0] (cid:197)SRC1[63:0] + SRC2[63:0]
DEST[127:64] (cid:197)SRC1[127:64]
DEST[MAX_VL-1:128] (cid:197)0

ADDSD (128-bit Legacy SSE version)

DEST[63:0] (cid:197)DEST[63:0] + SRC[63:0]
DEST[MAX_VL-1:64] (Unmodified)

Intel C/C++ Compiler Intrinsic Equivalent

VADDSD __m128d _mm_mask_add_sd (__m128d s, __mmask8 k, __m128d a, __m128d b);
VADDSD __m128d _mm_maskz_add_sd (__mmask8 k, __m128d a, __m128d b);
VADDSD __m128d _mm_add_round_sd (__m128d a, __m128d b, int);
VADDSD __m128d _mm_mask_add_round_sd (__m128d s, __mmask8 k, __m128d a, __m128d b, int);
VADDSD __m128d _mm_maskz_add_round_sd (__mmask8 k, __m128d a, __m128d b, int);
ADDSD __m128d _mm_add_sd (__m128d a, __m128d b);

SIMD Floating-Point Exceptions

Overflow, Underflow, Invalid, Precision, Denormal

Other Exceptions

VEX-encoded instruction, see Exceptions Type 3.

EVEX-encoded instruction, see Exceptions Type E3.