_mm_mask_rsqrt14_sd
Classification
AVX-512, Elementary Math Functions, CPUID Test: AVX512F
Header File
Instruction
VRSQRT14SD xmm {k}, xmm, xmm
Synopsis
_mm_mask_rsqrt14_sd(__m128d src, __mmask8 k, __m128d a, __m128d b);
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" using writemask "k" (the element is copied from "src" when mask bit 0 is not set), and copy the upper element from "a" to the upper element of "dst". The maximum relative error for this approximation is less than 2^-14.
Operation
IF k[0]
dst[63:0] := (1.0 / SQRT(b[63:0]))
ELSE
dst[63:0] := src[63:0]
FI
dst[127:64] := a[127:64]
dst[MAX:128] := 0