vmulph

Multiply Packed FP16 Values

VMULPH zmm1 {k1}, zmm2, zmm3/m512

Multiplies half-precision floating-point values.

Details

Multiplies 32 pairs of half-precision (FP16) floating-point values from zmm2 and zmm3/m512, storing the result in zmm1 with optional write masking via k1. Follows IEEE 754 semantics with rounding controlled by MXCSR. Requires AVX-512-FP16 extension. Exception flags in MXCSR are set per IEEE 754 rules (underflow, overflow, precision, invalid operation).

Pseudocode Operation

for i ← 0 to 31 do
  if (k1[i] or no_mask) then
    zmm1[16*i+15:16*i] ← FP16_MUL(zmm2[16*i+15:16*i], zmm3[16*i+15:16*i]);
  else if (zeroing_mask)
    zmm1[16*i+15:16*i] ← 0;
endfor;
// MXCSR exception flags updated per result

Example

VMULPH zmm1, zmm2, zmm3/m512

Encoding

Binary Layout

EVEX

Format EVEX

Opcode EVEX.512.NP.MAP5.W0 59 /r

Extension AVX-512-FP16

Operands

dest
512-bit ZMM AVX-512 register
src1
512-bit ZMM AVX-512 register
src2
512-bit ZMM AVX-512 register or Memory operand

Reference (Intel® SDM)

Instruction Forms

Opcode	Instruction	Op/En	64/32-bit Mode	CPUID	Description
EVEX.128.NP.MAP5.W0 59 /r	VMULPH xmm1{k1}{z}, xmm2, xmm3/m128/m16bcst	A	V/V	(AVX512_FP16 AND AVX512VL) OR AVX10.1	Multiply packed FP16 values from xmm3/m128/m16bcst to xmm2 and store the result in xmm1 subject to writemask k1.
EVEX.256.NP.MAP5.W0 59 /r	VMULPH ymm1{k1}{z}, ymm2, ymm3/m256/m16bcst	A	V/V	(AVX512_FP16 AND AVX512VL) OR AVX10.1	Multiply packed FP16 values from ymm3/m256/m16bcst to ymm2 and store the result in ymm1 subject to writemask k1.
EVEX.512.NP.MAP5.W0 59 /r	VMULPH zmm1{k1}{z}, zmm2, zmm3/m512/m16bcst {er}	A	V/V	AVX512_FP16 OR AVX10.1	Multiply packed FP16 values in zmm3/m512/m16bcst with zmm2 and store the result in zmm1 subject to writemask k1.

Instruction Operand Encoding

Op/En	Tuple Type	Operand 1	Operand 2	Operand 3	Operand 4
A	Full	ModRM:reg (w)	VEX.vvvv (r)	ModRM:r/m (r)	N/A

Description

This instruction multiplies packed FP16 values from source operands and stores the packed FP16 result in the destination operand. The destination elements are updated according to the writemask.

Operation

VMULPH (EVEX encoded versions) when src2 operand is a register
VL = 128, 256 or 512
KL := VL/16

IF (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*:
DEST.fp16[j] := SRC1.fp16[j] * SRC2.fp16[j]
ELSE IF *zeroing*:
DEST.fp16[j] := 0
// else dest.fp16[j] remains unchanged

DEST[MAXVL-1:VL] := 0





VMULPH—Multiply Packed FP16 Values                                                                                                          Vol. 2C 5-430
VMULPH (EVEX encoded versions) when src2 operand is a memory source
VL = 128, 256 or 512
KL := VL/16

FOR j := 0 TO KL-1:
IF k1[j] OR *no writemask*:
IF EVEX.b = 1:
DEST.fp16[j] := SRC1.fp16[j] * SRC2.fp16[0]
ELSE:
DEST.fp16[j] := SRC1.fp16[j] * SRC2.fp16[j]
ELSE IF *zeroing*:
DEST.fp16[j] := 0
// else dest.fp16[j] remains unchanged

DEST[MAXVL-1:VL] := 0

Intel C/C++ Compiler Intrinsic Equivalent

VMULPH __m128h _mm_mask_mul_ph (__m128h src, __mmask8 k, __m128h a, __m128h b);
VMULPH __m128h _mm_maskz_mul_ph (__mmask8 k, __m128h a, __m128h b);
VMULPH __m128h _mm_mul_ph (__m128h a, __m128h b);
VMULPH __m256h _mm256_mask_mul_ph (__m256h src, __mmask16 k, __m256h a, __m256h b);
VMULPH __m256h _mm256_maskz_mul_ph (__mmask16 k, __m256h a, __m256h b);
VMULPH __m256h _mm256_mul_ph (__m256h a, __m256h b);
VMULPH __m512h _mm512_mask_mul_ph (__m512h src, __mmask32 k, __m512h a, __m512h b);
VMULPH __m512h _mm512_maskz_mul_ph (__mmask32 k, __m512h a, __m512h b);
VMULPH __m512h _mm512_mul_ph (__m512h a, __m512h b);
VMULPH __m512h _mm512_mask_mul_round_ph (__m512h src, __mmask32 k, __m512h a, __m512h b, int rounding);
VMULPH __m512h _mm512_maskz_mul_round_ph (__mmask32 k, __m512h a, __m512h b, int rounding);
VMULPH __m512h _mm512_mul_round_ph (__m512h a, __m512h b, int rounding);

Exceptions

SIMD Floating-Point Exceptions

Invalid, Underflow, Overflow, Precision, Denormal

Other Exceptions

EVEX-encoded instructions, see Table 2-48, “Type E2 Class Exception Conditions.” VMULPH—Multiply Packed FP16 Values Vol. 2C 5-431