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Source code

VCVTPD2PH

Convert Packed Double Precision FP Values to Packed FP16 Values

stableVMJITAOTinstruction

Encodings

OpcodeInstructionOp/En64-bitCompat/LegacyDescription
EVEX.128.66.MAP5.W1 5A /rVCVTPD2PH xmm1{k1}{z}, xmm2/m128/m64bcstAValidValidConvert two packed double precision floating- AND AVX512VL) point values in xmm2/m128/m64bcst to two OR AVX10.1 packed FP16 values, and store the result in xmm1 subject to writemask k1.
EVEX.256.66.MAP5.W1 5A /rVCVTPD2PH xmm1{k1}{z}, ymm2/m256/m64bcstAValidValidConvert four packed double precision floating- AND AVX512VL) point values in ymm2/m256/m64bcst to four OR AVX10.1 packed FP16 values, and store the result in xmm1 subject to writemask k1.
EVEX.512.66.MAP5.W1 5A /rVCVTPD2PH xmm1{k1}{z}, zmm2/m512/m64bcst {er}AValidValidConvert eight packed double precision floating- OR AVX10.1 point values in zmm2/m512/m64bcst to eight packed FP16 values, and store the result in ymm1 subject to writemask k1.

Operand encoding

Each mode is a value of the Op/En column above. It says which field of the encoded instruction carries each operand, in the order they are written, and whether the instruction reads it, writes it or both.

A

  1. modrm.reg escrituraModRM byte, reg field (bits 5-3)
  2. modrm.rm lecturaModRM byte, r/m field (bits 2-0); with the SIB byte and the displacement when the mod field asks for them

Tupla: Full

Measured cost

Loading measurements from arch-data...

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 intrinsics

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 2-48, "Type E2 Class Exception Conditions."

Sources