| Opcode/Instruction | Op/En | 64/32 bit Mode Support | CPUID Feature Flag | Description |
|---|---|---|---|---|
| EVEX.128.66.MAP5.W1 5A /r VCVTPD2PH xmm1{k1}{z}, xmm2/m128/m64bcst | A | V/V | AVX512-FP16 AVX512VL | Convert two packed double precision floating-point values in xmm2/m128/m64bcst to two packed FP16 values, and store the result in xmm1 subject to writemask k1. |
| EVEX.256.66.MAP5.W1 5A /r VCVTPD2PH xmm1{k1}{z}, ymm2/m256/m64bcst | A | V/V | AVX512-FP16 AVX512VL | Convert four packed double precision floating-point values in ymm2/m256/m64bcst to four packed FP16 values, and store the result in xmm1 subject to writemask k1. |
| EVEX.512.66.MAP5.W1 5A /r VCVTPD2PH xmm1{k1}{z}, zmm2/m512/m64bcst {er} | A | V/V | AVX512-FP16 | Convert eight packed double precision floating-point values in zmm2/m512/m64bcst to eight packed FP16 values, and store the result in ymm1 subject to writemask k1. |
| Op/En | Tuple | Operand 1 | Operand 2 | Operand 3 | Operand 4 |
|---|---|---|---|---|---|
| A | Full | ModRM:reg (w) | ModRM:r/m (r) | N/A | N/A |
Description
This instruction converts two, four, or eight packed double precision floating-point values in the source operand (second operand) to two, four, or eight packed FP16 values in the destination operand (first operand). When a conversion is inexact, the value returned is rounded according to the rounding control bits in the MXCSR register or the embedded rounding control bits.
EVEX encoded versions: The source operand is a ZMM/YMM/XMM register, a 512/256/128-bit memory location, or a 512/256/128-bit vector broadcasts from a 64-bit memory location. The destination operand is a XMM register conditionally updated with writemask k1. The upper bits (MAXVL-1:128/64/32) of the corresponding destination are zeroed.
EVEX.vvvv are reserved and must be 1111b otherwise instructions will #UD.
This instruction uses MXCSR.DAZ for handling FP64 inputs. FP16 outputs can be normal or denormal, and are not conditionally flushed to zero.
Operation
VCVTPD2PH DEST, SRC
VL = 128, 256 or 512
KL := VL / 64
IF *SRC is a register* and (VL = 512) AND (EVEX.b = 1):
SET_RM(EVEX.RC)
ELSE:
SET_RM(MXCSR.RC)
FOR j := 0 TO KL-1:
IF k1[j] OR *no writemask*:
IF *SRC is memory* and EVEX.b = 1:
tsrc := SRC.double[0]
ELSE
tsrc := SRC.double[j]
DEST.fp16[j] := Convert_fp64_to_fp16(tsrc)
ELSE IF *zeroing*:
DEST.fp16[j] := 0
// else dest.fp16[j] remains unchanged
DEST[MAXVL-1:VL/4] := 0
Intel C/C++ Compiler Intrinsic Equivalent
VCVTPD2PH __m128h _mm512_cvt_roundpd_ph (__m512d a, int rounding);
VCVTPD2PH __m128h _mm512_mask_cvt_roundpd_ph (__m128h src, __mmask8 k, __m512d a, int rounding);
VCVTPD2PH __m128h _mm512_maskz_cvt_roundpd_ph (__mmask8 k, __m512d a, int rounding);
VCVTPD2PH __m128h _mm_cvtpd_ph (__m128d a);
VCVTPD2PH __m128h _mm_mask_cvtpd_ph (__m128h src, __mmask8 k, __m128d a);
VCVTPD2PH __m128h _mm_maskz_cvtpd_ph (__mmask8 k, __m128d a);
VCVTPD2PH __m128h _mm256_cvtpd_ph (__m256d a);
VCVTPD2PH __m128h _mm256_mask_cvtpd_ph (__m128h src, __mmask8 k, __m256d a);
VCVTPD2PH __m128h _mm256_maskz_cvtpd_ph (__mmask8 k, __m256d a);
VCVTPD2PH __m128h _mm512_cvtpd_ph (__m512d a);
VCVTPD2PH __m128h _mm512_mask_cvtpd_ph (__m128h src, __mmask8 k, __m512d a);
VCVTPD2PH __m128h _mm512_maskz_cvtpd_ph (__mmask8 k, __m512d a);
SIMD Floating-Point Exceptions
Invalid, Underflow, Overflow, Precision, Denormal.
Other Exceptions
EVEX-encoded instructions, see Table 2-46, “Type E2 Class Exception Conditions.”