| Opcode/Instruction | Op/En | 64/32 bit Mode Support | CPUID Feature Flag | Description |
|---|---|---|---|---|
| EVEX.LLIG.F2.MAP5.W1 5A /r VCVTSD2SH xmm1{k1}{z}, xmm2, xmm3/m64 {er} | A | V/V | AVX512-FP16 | Convert the low FP64 value in xmm3/m64 to an FP16 value and store the result in the low element of xmm1 subject to writemask k1. Bits 127:16 of xmm2 are copied to xmm1[127:16]. |
| 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 FP64 value in the second source operand to an FP16 value, and stores the result in the low element of the destination operand.
When the conversion is inexact, the value returned is rounded according to the rounding control bits in the MXCSR register.
Bits 127:16 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 FP16 element of the destination is updated according to the writemask.
Operation
VCVTSD2SH dest, src1, src2
IF *SRC2 is a register* and (EVEX.b = 1):
SET_RM(EVEX.RC)
ELSE:
SET_RM(MXCSR.RC)
IF k1[0] OR *no writemask*:
DEST.fp16[0] := Convert_fp64_to_fp16(SRC2.fp64[0])
ELSE IF *zeroing*:
DEST.fp16[0] := 0
// else dest.fp16[0] remains unchanged
DEST[127:16] := SRC1[127:16]
DEST[MAXVL-1:128] := 0
Intel C/C++ Compiler Intrinsic Equivalent
VCVTSD2SH __m128h _mm_cvt_roundsd_sh (__m128h a, __m128d b, const int rounding);
VCVTSD2SH __m128h _mm_mask_cvt_roundsd_sh (__m128h src, __mmask8 k, __m128h a, __m128d b, const int rounding);
VCVTSD2SH __m128h _mm_maskz_cvt_roundsd_sh (__mmask8 k, __m128h a, __m128d b, const int rounding);
VCVTSD2SH __m128h _mm_cvtsd_sh (__m128h a, __m128d b);
VCVTSD2SH __m128h _mm_mask_cvtsd_sh (__m128h src, __mmask8 k, __m128h a, __m128d b);
VCVTSD2SH __m128h _mm_maskz_cvtsd_sh (__mmask8 k, __m128h a, __m128d b);
SIMD Floating-Point Exceptions
Invalid, Underflow, Overflow, Precision, Denormal.
Other Exceptions
EVEX-encoded instructions, see Table 2-47, “Type E3 Class Exception Conditions.”