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CVTSS2SD—Convert Scalar Single-Precision Floating-Point Value to Scalar Double-Precision Floating-Point Value

Opcode/Instruction Op /En 64/32 bit Mode Support CPUID Feature Flag Description
F3 0F 5A /r CVTSS2SD xmm1, xmm2/m32 RM V/V SSE2 Convert one single-precision floating-point value in xmm2/m32 to one double-precision floating-point value in xmm1.
VEX.NDS.128.F3.0F.WIG 5A /r VCVTSS2SD xmm1, xmm2, xmm3/m32 RVM V/V AVX Convert one single-precision floating-point value in xmm3/m32 to one double-precision floating-point value and merge with high bits of xmm2.
EVEX.NDS.LIG.F3.0F.W0 5A /r VCVTSS2SD xmm1 {k1}{z}, xmm2, xmm3/m32{sae} T1S V/V AVX512F Convert one single-precision floating-point value in xmm3/m32 to one double-precision floating-point value and merge with high bits of xmm2 under writemask k1.

Instruction Operand Encoding

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

Description

Converts a single-precision floating-point value in the “convert-from” source operand to a double-precision floating-point value in the destination operand. When the “convert-from” source operand is an XMM register, the single-precision floating-point value is contained in the low doubleword of the register. The result is stored in the low quadword of the destination operand.

128-bit Legacy SSE version: The “convert-from” source operand (the second operand) is an XMM register or memory location. Bits (MAX_VL-1:64) of the corresponding destination register remain unchanged. The destina-tion operand is an XMM register.

VEX.128 and EVEX encoded versions: The “convert-from” source operand (the third operand) can be an XMM register or a 32-bit memory location. The first source and destination operands are XMM registers. Bits (127:64) of the XMM register destination are copied from the corresponding bits in the first source operand. Bits (MAX_VL-1:128) of the destination register are zeroed.

Software should ensure VCVTSS2SD is encoded with VEX.L=0. Encoding VCVTSS2SD with VEX.L=1 may encounter unpredictable behavior across different processor generations.

Operation


VCVTSS2SD (EVEX encoded version)

IF k1[0] or *no writemask*
    THEN
    DEST[63:0] (cid:197) Convert_Single_Precision_To_Double_Precision_Floating_Point(SRC2[31:0]);
    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] (cid:197) SRC1[127:64]
DEST[MAX_VL-1:128] (cid:197) 0


VCVTSS2SD (VEX.128 encoded version)

DEST[63:0] (cid:197)Convert_Single_Precision_To_Double_Precision_Floating_Point(SRC2[31:0])
DEST[127:64] (cid:197)SRC1[127:64]
DEST[MAX_VL-1:128] (cid:197)0


CVTSS2SD (128-bit Legacy SSE version)

DEST[63:0] (cid:197)Convert_Single_Precision_To_Double_Precision_Floating_Point(SRC[31:0]);
DEST[MAX_VL-1:64] (Unmodified)



Intel C/C++ Compiler Intrinsic Equivalent


VCVTSS2SD __m128d _mm_cvt_roundss_sd(__m128d a, __m128 b, int r);
VCVTSS2SD __m128d _mm_mask_cvt_roundss_sd(__m128d s, __mmask8 m, __m128d a,__m128 b, int r);
VCVTSS2SD __m128d _mm_maskz_cvt_roundss_sd(__mmask8 k, __m128d a, __m128 a, int r);
VCVTSS2SD __m128d _mm_mask_cvtss_sd(__m128d s, __mmask8 m, __m128d a,__m128 b);
VCVTSS2SD __m128d _mm_maskz_cvtss_sd(__mmask8 m, __m128d a,__m128 b);
CVTSS2SD __m128d_mm_cvtss_sd(__m128d a, __m128 a);



SIMD Floating-Point Exceptions


Invalid, Denormal


Other Exceptions





VEX-encoded instructions, see Exceptions Type 3.



EVEX-encoded instructions, see Exceptions Type E3.