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

Instruction Operand Encoding

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