VSUBSH - Subtract Scalar FP16 Value

Opcode/ Instruction

Op/ En

64/32 bit Mode Support

CPUID Feature Flag

Description

EVEX.LLIG.F3.MAP5.W0 5C /r VSUBSH xmm1{k1}{z}, xmm2, xmm3/m16 {er}

A

V/V

AVX512-FP16

Subtract the low FP16 value in xmm3/m16 from xmm2 and store the result in xmm1 subject to writemask k1. Bits 127:16 from xmm2 are copied to xmm1[127:16].

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)

N/A

Description

This instruction subtracts the low FP16 value from the second source operand from the corresponding value in the first source operand, storing the FP16 result in the destination operand. Bits 127:16 of the destination operand are copied from the corresponding bits of the first source operand. Bits MAXVL-1:128 of the destination operand are zeroed. The low FP16 element of the destination is updated according to the writemask.

Operation

VSUBSH (EVEX encoded versions) 

IF EVEX.b = 1 and SRC2 is a register:
   SET_RM(EVEX.RC)
ELSE
   SET_RM(MXCSR.RC)
IF k1[0] OR *no writemask*:
   DEST.fp16[0] := SRC1.fp16[0] - SRC2.fp16[0]
ELSE IF *zeroing*:
   DEST.fp16[0] := 0
// else dest.fp16[0] remains unchanged
DEST[127:16] := SRC1[127:16]
DEST[MAXVL-1:128] := 0

Intel C/C++ Compiler Intrinsic Equivalent 

VSUBSH __m128h _mm_mask_sub_round_sh (__m128h src, __mmask8 k, __m128h a, __m128h b, int rounding);
VSUBSH __m128h _mm_maskz_sub_round_sh (__mmask8 k, __m128h a, __m128h b, int rounding);
VSUBSH __m128h _mm_sub_round_sh (__m128h a, __m128h b, int rounding);
VSUBSH __m128h _mm_mask_sub_sh (__m128h src, __mmask8 k, __m128h a, __m128h b);
VSUBSH __m128h _mm_maskz_sub_sh (__mmask8 k, __m128h a, __m128h b);
VSUBSH __m128h _mm_sub_sh (__m128h a, __m128h b);

SIMD Floating-Point Exceptions

Invalid, Underflow, Overflow, Precision, Denormal.

Other Exceptions

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