_mm256_maskz_roundscale_pd
Classification
AVX-512, Miscellaneous, CPUID Test: AVX512F
Header File
Instruction
VRNDSCALEPD ymm {z}, ymm, imm8
Synopsis
_mm256_maskz_roundscale_pd(__mmask8 k, __m256d a, int imm8);
Description
Round packed double-precision (64-bit) floating-point elements in "a" to the number of fraction bits specified by "imm8", and store the results in "dst" using zeromask "k" (elements are zeroed out when the corresponding mask bit is not set). [round_imm_note]
Operation
DEFINE RoundScaleFP64(src1[63:0], imm8[7:0]) {
m[63:0] := FP64(imm8[7:4]) // number of fraction bits after the binary point to be preserved
tmp[63:0] := POW(2.0, -m) * ROUND(POW(2.0, m) * src1[63:0], imm8[3:0])
IF IsInf(tmp[63:0])
tmp[63:0] := src1[63:0]
FI
RETURN tmp[63:0]
}
FOR j := 0 to 3
i := j*64
IF k[j]
dst[i+63:i] := RoundScaleFP64(a[i+63:i], imm8[7:0])
ELSE
dst[i+63:i] := 0
FI
ENDFOR
dst[MAX:256] := 0