VCVTPH2PD

VCVTPH2PD — Convert Packed FP16 Values to FP64 Values

Opcode/ Instruction	Op/ En	64/32 Bit Mode Support	CPUID Feature Flag	Description
EVEX.128.NP.MAP5.W0 5A /r VCVTPH2PD xmm1{k1}{z}, xmm2/m32/m16bcst	A	V/V	(AVX512_FP16 AND AVX512VL) OR AVX10.1	Convert packed FP16 values in xmm2/m32/m16bcst to FP64 values, and store result in xmm1 subject to writemask k1.
EVEX.256.NP.MAP5.W0 5A /r VCVTPH2PD ymm1{k1}{z}, xmm2/m64/m16bcst	A	V/V	(AVX512_FP16 AND AVX512VL) OR AVX10.1	Convert packed FP16 values in xmm2/m64/m16bcst to FP64 values, and store result in ymm1 subject to writemask k1.
EVEX.512.NP.MAP5.W0 5A /r VCVTPH2PD zmm1{k1}{z}, xmm2/m128/m16bcst {sae}	A	V/V	AVX512_FP16 OR AVX10.1	Convert packed FP16 values in xmm2/m128/m16bcst to FP64 values, and store result in zmm1 subject to writemask k1.

Instruction Operand Encoding

Op/En	Tuple	Operand 1	Operand 2	Operand 3	Operand 4
A	Quarter	ModRM:reg (w)	ModRM:r/m (r)	N/A	N/A

Description

This instruction converts packed FP16 values to FP64 values in the destination register. The destination elements are updated according to the writemask.

This instruction handles both normal and denormal FP16 inputs.

Operation

VCVTPH2PD DEST, SRC

VL = 128, 256, or 512
KL ← VL/64
FOR j ← 0 TO KL-1:
    IF k1[j] OR *no writemask*:
        IF *SRC is memory* and EVEX.b = 1:
            tsrc ← SRC.fp16[0]
        ELSE
            tsrc ← SRC.fp16[j]
        DEST.fp64[j] ← Convert_fp16_to_fp64(tsrc)
    ELSE IF *zeroing*:
        DEST.fp64[j] ← 0
    // else dest.fp64[j] remains unchanged

Intel C/C++ Compiler Intrinsic Equivalent

VCVTPH2PD __m512d _mm512_cvt_roundph_pd (__m128h a, int sae);
VCVTPH2PD __m512d _mm512_mask_cvt_roundph_pd (__m512d src, __mmask8 k, __m128h a, int sae);
VCVTPH2PD __m512d _mm512_maskz_cvt_roundph_pd (__mmask8 k, __m128h a, int sae);
VCVTPH2PD __m128d _mm_cvtph_pd (__m128h a);
VCVTPH2PD __m128d _mm_mask_cvtph_pd (__m128d src, __mmask8 k, __m128h a);
VCVTPH2PD __m128d _mm_maskz_cvtph_pd (__mmask8 k, __m128h a);
VCVTPH2PD __m256d _mm256_cvtph_pd (__m128h a);
VCVTPH2PD __m256d _mm256_mask_cvtph_pd (__m256d src, __mmask8 k, __m128h a);
VCVTPH2PD __m256d _mm256_maskz_cvtph_pd (__mmask8 k, __m128h a);
VCVTPH2PD __m512d _mm512_cvtph_pd (__m128h a);
VCVTPH2PD __m512d _mm512_mask_cvtph_pd (__m512d src, __mmask8 k, __m128h a);
VCVTPH2PD __m512d _mm512_maskz_cvtph_pd (__mmask8 k, __m128h a);

SIMD Floating-Point Exceptions

Invalid, Denormal.

Other Exceptions

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Source: Intel® 64 and IA-32 Architectures Software Developer's Manual, Combined Volumes (Order Number 325462-091US, March 2026)
Generated: 7-6-2026