VCMPSH - Compare Scalar FP16 Values

Opcode/ Instruction

Op/ En

64/32 bit Mode Support

CPUID Feature Flag

Description

EVEX.LLIG.F3.0F3A.W0 C2 /r /ib VCMPSH k1{k2}, xmm2, xmm3/m16 {sae}, imm8

A

V/V

AVX512-FP16

Compare low FP16 values in xmm3/m16 and xmm2 using bits 4:0 of imm8 as a comparison predicate subject to writemask k2, and store the result in mask register k1.

Instruction Operand Encoding

Op/En

Tuple

Operand 1

Operand 2

Operand 3

Operand 4

A

Scalar

ModRM:reg (w)

VEX.vvvv (r)

ModRM:r/m (r)

imm8 (r)

Description

This instruction compares the FP16 values from the lowest element of the source operands and stores the result in the destination mask operand. The comparison predicate operand (immediate byte bits 4:0) specifies the type of comparison performed on the pair of packed FP16 values. The low destination bit is updated according to the writemask. Bits MAXKL-1:1 of the destination operand are zeroed.

Operation 

CASE (imm8 & 0x1F) OF
0: CMP_OPERATOR := EQ_OQ;
1: CMP_OPERATOR := LT_OS;
2: CMP_OPERATOR := LE_OS;
3: CMP_OPERATOR := UNORD_Q;
4: CMP_OPERATOR := NEQ_UQ;
5: CMP_OPERATOR := NLT_US;
6: CMP_OPERATOR := NLE_US;
7: CMP_OPERATOR := ORD_Q;
8: CMP_OPERATOR := EQ_UQ;
9: CMP_OPERATOR := NGE_US;
10: CMP_OPERATOR := NGT_US;
11: CMP_OPERATOR := FALSE_OQ;
12: CMP_OPERATOR := NEQ_OQ;
13: CMP_OPERATOR := GE_OS;
14: CMP_OPERATOR := GT_OS;
15: CMP_OPERATOR := TRUE_UQ;
16: CMP_OPERATOR := EQ_OS;
17: CMP_OPERATOR := LT_OQ;
18: CMP_OPERATOR := LE_OQ;
19: CMP_OPERATOR := UNORD_S;
20: CMP_OPERATOR := NEQ_US;
21: CMP_OPERATOR := NLT_UQ;
22: CMP_OPERATOR := NLE_UQ;
23: CMP_OPERATOR := ORD_S;
24: CMP_OPERATOR := EQ_US;
25: CMP_OPERATOR := NGE_UQ;
26: CMP_OPERATOR := NGT_UQ;
27: CMP_OPERATOR := FALSE_OS;
28: CMP_OPERATOR := NEQ_OS;
29: CMP_OPERATOR := GE_OQ;
30: CMP_OPERATOR := GT_OQ;
31: CMP_OPERATOR := TRUE_US;
ESAC

VCMPSH (EVEX Encoded Versions) 

IF k2[0] OR *no writemask*:
   DEST.bit[0] := SRC1.fp16[0] CMP_OPERATOR SRC2.fp16[0]
ELSE
   DEST.bit[0] := 0
DEST[MAXKL-1:1] := 0

Intel C/C++ Compiler Intrinsic Equivalent 

VCMPSH __mmask8 _mm_cmp_round_sh_mask (__m128h a, __m128h b, const int imm8, const int sae);
VCMPSH __mmask8 _mm_mask_cmp_round_sh_mask (__mmask8 k1, __m128h a, __m128h b, const int imm8, const int sae);
VCMPSH __mmask8 _mm_cmp_sh_mask (__m128h a, __m128h b, const int imm8);
VCMPSH __mmask8 _mm_mask_cmp_sh_mask (__mmask8 k1, __m128h a, __m128h b, const int imm8);

SIMD Floating-Point Exceptions

Invalid, Denormal.

Other Exceptions

EVEX-encoded instructions, see Table 2-47, "Type E3 Class Exception Conditions."