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 A V/V SSE2 Add the low double-precision floating-point value from xmm2/mem to xmm1 and store the result in xmm1.
VEX.LIG.F2.0F.WIG 58 /r VADDSD xmm1, xmm2, xmm3/m64 B V/V AVX Add the low double-precision floating-point value from xmm3/mem to xmm2 and store the result in xmm1.
EVEX.LLIG.F2.0F.W1 58 /r VADDSD xmm1 {k1}{z}, xmm2, xmm3/m64{er} C 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 Tuple Type Operand 1 Operand 2 Operand 3 Operand 4
A NA ModRM:reg (r, w) ModRM:r/m (r) NA NA
B NA ModRM:reg (w) VEX.vvvv (r) ModRM:r/m (r) NA
C Tuple1 Scalar ModRM:reg (w) EVEX.vvvv (r) 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 (MAXVL-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 (MAXVL-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_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;
DEST[127:64] := SRC1[127:64]
DEST[MAXVL-1:128] := 0

VADDSD (VEX.128 encoded version)

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

ADDSD (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

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 Table 2-20, “Type 3 Class Exception Conditions”.
EVEX-encoded instruction, see Table 2-47, “Type E3 Class Exception Conditions”.