x86doc › VSQRTSH - Compute Square Root of Scalar FP16 Value

Opcode/Instruction | Op/En | 64/32 bit Mode Support | CPUID Feature Flag | Description |
---|---|---|---|---|

EVEX.LLIG.F3.MAP5.W0 51 /r VSQRTSH xmm1{k1}{z}, xmm2, xmm3/m16 {er} | A | V/V | AVX512-FP16 | Compute square root of the low FP16 value in xmm3/m16 and store the result in xmm1 subject to writemask k1. Bits 127:16 from xmm2 are copied to xmm1[127:16]. |

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 performs a scalar FP16 square-root computation on the source operand and stores 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**

**VSQRTSH dest{k1}, src1, src2**

IF k1[0] or *no writemask*:

DEST.fp16[0] := SQRT(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**

VSQRTSH __m128h _mm_mask_sqrt_round_sh (__m128h src, __mmask8 k, __m128h a, __m128h b, const int rounding);

VSQRTSH __m128h _mm_maskz_sqrt_round_sh (__mmask8 k, __m128h a, __m128h b, const int rounding);

VSQRTSH __m128h _mm_sqrt_round_sh (__m128h a, __m128h b, const int rounding);

VSQRTSH __m128h _mm_mask_sqrt_sh (__m128h src, __mmask8 k, __m128h a, __m128h b);

VSQRTSH __m128h _mm_maskz_sqrt_sh (__mmask8 k, __m128h a, __m128h b);

VSQRTSH __m128h _mm_sqrt_sh (__m128h a, __m128h b);

**SIMD Floating-Point Exceptions**

Invalid, Precision, Denormal

**Other Exceptions**

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