_mm_rsqrt28_round_sd
Classification
AVX-512, Elementary Math Functions, CPUID Test: AVX512ER
Header File
Instruction
VRSQRT28SD xmm, xmm, xmm {sae}
Synopsis
_mm_rsqrt28_round_sd(__m128d a, __m128d b, int sae);
Description
Compute the approximate reciprocal square root of the lower double-precision (64-bit) floating-point element in "b", store the result in the lower element of "dst", and copy the upper element from "a" to the upper element of "dst". The maximum relative error for this approximation is less than 2^-28. [sae_note]
Operation
dst[63:0] := (1.0 / SQRT(b[63:0]))
dst[127:64] := a[127:64]
dst[MAX:128] := 0