_mm_mask_reduce_round_ss
Classification
AVX-512, Miscellaneous, CPUID Test: AVX512DQ
Header File
Instruction
VREDUCESS xmm {k}, xmm, xmm {sae}, imm8
Synopsis
_mm_mask_reduce_round_ss(__m128 src, __mmask8 k, __m128 a, __m128 b, int imm8, int sae);
Description
Extract the reduced argument of the lower single-precision (32-bit) floating-point element in "b" by the number of bits specified by "imm8", 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 3 packed elements from "a" to the upper elements of "dst". [round_imm_note][sae_note]
Operation
DEFINE ReduceArgumentPS(src1[31:0], imm8[7:0]) {
m[31:0] := FP32(imm8[7:4]) // number of fraction bits after the binary point to be preserved
tmp[31:0] := POW(FP32(2.0), -m) * ROUND(POW(FP32(2.0), m) * src1[31:0], imm8[3:0])
tmp[31:0] := src1[31:0] - tmp[31:0]
IF IsInf(tmp[31:0])
tmp[31:0] := FP32(0.0)
FI
RETURN tmp[31:0]
}
IF k[0]
dst[31:0] := ReduceArgumentPS(b[31:0], imm8[7:0])
ELSE
dst[31:0] := src[31:0]
FI
dst[127:32] := a[127:32]
dst[MAX:128] := 0