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Source code

VMAXPH

Return Maximum of Packed FP16 Values

stableVMJITAOTinstruction

Encodings

OpcodeInstructionOp/En64-bitCompat/LegacyDescription
EVEX.128.NP.MAP5.W0 5F /rVMAXPH xmm1{k1}{z}, xmm2, xmm3/m128/m16bcstAValidValidReturn the maximum packed FP16 values AND AVX512VL) between xmm2 and xmm3/m128/m16bcst and OR AVX10.1 store the result in xmm1 subject to writemask k1.
EVEX.256.NP.MAP5.W0 5F /rVMAXPH ymm1{k1}{z}, ymm2, ymm3/m256/m16bcstAValidValidReturn the maximum packed FP16 values AND AVX512VL) between ymm2 and ymm3/m256/m16bcst and OR AVX10.1 store the result in ymm1 subject to writemask k1.
EVEX.512.NP.MAP5.W0 5F /rVMAXPH zmm1{k1}{z}, zmm2, zmm3/m512/m16bcst {sae}AValidValidReturn the maximum packed FP16 values OR AVX10.1 between zmm2 and zmm3/m512/m16bcst and store the result in zmm1 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. vex.vvvv lecturaVEX prefix, vvvv field (inverted)
  3. 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 performs a SIMD compare of the packed FP16 values in the first source operand and the second source operand and returns the maximum value for each pair of values to the destination operand.

If the values being compared are both 0.0s (of either sign), the value in the second operand (source operand) is returned. If a value in the second operand is an SNaN, then SNaN is forwarded unchanged to the destination (that is, a QNaN version of the SNaN is not returned).

If only one value is a NaN (SNaN or QNaN) for this instruction, the second operand (source operand), either a NaN or a valid floating-point value, is written to the result. If instead of this behavior, it is required that the NaN source operand (from either the first or second operand) be returned, the action of VMAXPH can be emulated using a sequence of instructions, such as, a comparison followed by AND, ANDN and OR.

EVEX encoded versions: The first source operand (the second operand) is a ZMM/YMM/XMM register. The second source operand can be a ZMM/YMM/XMM register, a 512/256/128-bit memory location or a 512/256/128-bit vector broadcast from a 16-bit memory location. The destination operand is a ZMM/YMM/XMM register conditionally updated with writemask k1.

Operation

def MAX(SRC1, SRC2):
    IF (SRC1 = 0.0) and (SRC2 = 0.0):
          DEST := SRC2
    ELSE IF (SRC1 = NaN):
          DEST := SRC2
    ELSE IF (SRC2 = NaN):
          DEST := SRC2
    ELSE IF (SRC1 > SRC2):
          DEST := SRC1
    ELSE:
          DEST := SRC2


VMAXPH dest, src1, src2
VL = 128, 256 or 512
KL := VL/16

FOR j := 0 TO KL-1:
    IF k1[j] OR *no writemask*:
          IF EVEX.b = 1:
                tsrc2 := SRC2.fp16[0]
          ELSE:
                tsrc2 := SRC2.fp16[j]
          DEST.fp16[j] := MAX(SRC1.fp16[j], tsrc2)
    ELSE IF *zeroing*:
          DEST.fp16[j] := 0
    // else dest.fp16[j] remains unchanged

DEST[MAXVL-1:VL] := 0

Intel C/C++ compiler intrinsics

VMAXPH __m128h _mm_mask_max_ph (__m128h src, __mmask8 k, __m128h a, __m128h b);
VMAXPH __m128h _mm_maskz_max_ph (__mmask8 k, __m128h a, __m128h b);
VMAXPH __m128h _mm_max_ph (__m128h a, __m128h b);
VMAXPH __m256h _mm256_mask_max_ph (__m256h src, __mmask16 k, __m256h a, __m256h b);
VMAXPH __m256h _mm256_maskz_max_ph (__mmask16 k, __m256h a, __m256h b);
VMAXPH __m256h _mm256_max_ph (__m256h a, __m256h b);
VMAXPH __m512h _mm512_mask_max_ph (__m512h src, __mmask32 k, __m512h a, __m512h b);
VMAXPH __m512h _mm512_maskz_max_ph (__mmask32 k, __m512h a, __m512h b);
VMAXPH __m512h _mm512_max_ph (__m512h a, __m512h b);
VMAXPH __m512h _mm512_mask_max_round_ph (__m512h src, __mmask32 k, __m512h a, __m512h b, int sae);
VMAXPH __m512h _mm512_maskz_max_round_ph (__mmask32 k, __m512h a, __m512h b, int sae);
VMAXPH __m512h _mm512_max_round_ph (__m512h a, __m512h b, int sae);

SIMD Floating-Point Exceptions

Invalid, Denormal.

Other Exceptions

EVEX-encoded instructions, see Table 2-48, "Type E2 Class Exception Conditions."

Sources