_mm_roundscale_pd
Classification
AVX-512, Miscellaneous, CPUID Test: AVX512F
Header File
Instruction
VRNDSCALEPD xmm, xmm, imm8
Synopsis
_mm_roundscale_pd(__m128d 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". [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 1
i := j*64
dst[i+63:i] := RoundScaleFP64(a[i+63:i], imm8[7:0])
ENDFOR
dst[MAX:128] := 0