VCVTSH2SD - Convert Low FP16 Value to an FP64 Value

Opcode/ Instruction

Op/ En

64/32 bit Mode Support

CPUID Feature Flag

Description

EVEX.LLIG.F3.MAP5.W0 5A /r VCVTSH2SD xmm1{k1}{z}, xmm2, xmm3/m16 {sae}

A

V/V

AVX512-FP16

Convert the low FP16 value in xmm3/m16 to an FP64 value and store the result in the low element of xmm1 subject to writemask k1. Bits 127:64 of xmm2 are copied to xmm1[127:64].

Instruction Operand Encoding

Op/En

Tuple

Operand 1

Operand 2

Operand 3

Operand 4

A

Scalar

ModRM:reg (w)

VEX.vvvv (r)

ModRM:r/m (r)

N/A

Description

This instruction converts the low FP16 element in the second source operand to a FP64 element in the low element of the destination operand.

Bits 127:64 of the destination operand are copied from the corresponding bits of the first source operand. Bits MAXVL-1:128 of the destination operand are zeroed. The low FP64 element of the destination is updated according to the writemask.

Operation

VCVTSH2SD dest, src1, src2 

IF k1[0] OR *no writemask*:
   DEST.fp64[0] := Convert_fp16_to_fp64(SRC2.fp16[0])
ELSE IF *zeroing*:
   DEST.fp64[0] := 0
// else dest.fp64[0] remains unchanged
DEST[127:64] := SRC1[127:64]
DEST[MAXVL-1:128] := 0

Intel C/C++ Compiler Intrinsic Equivalent 

VCVTSH2SD __m128d _mm_cvt_roundsh_sd (__m128d a, __m128h b, const int sae);
VCVTSH2SD __m128d _mm_mask_cvt_roundsh_sd (__m128d src, __mmask8 k, __m128d a, __m128h b, const int sae);
VCVTSH2SD __m128d _mm_maskz_cvt_roundsh_sd (__mmask8 k, __m128d a, __m128h b, const int sae);
VCVTSH2SD __m128d _mm_cvtsh_sd (__m128d a, __m128h b);
VCVTSH2SD __m128d _mm_mask_cvtsh_sd (__m128d src, __mmask8 k, __m128d a, __m128h b);
VCVTSH2SD __m128d _mm_maskz_cvtsh_sd (__mmask8 k, __m128d a, __m128h b);

SIMD Floating-Point Exceptions

Invalid, Denormal.

Other Exceptions

EVEX-encoded instructions, see Table 2-47, "Type E3 Class Exception Conditions."