permute 指令

AVX

1.

VPERMILPD — Permute Double-Precision Floating-Point Values

VPERMILPD xmm1, xmm2,xmm3/m128

Permute double-precision
floating-point values in
xmm2 using controls from
xmm3/mem and store result

in xmm1.

從imm8或者是xmm3寄存器中，選取src或者dest.

類似於shuffle

2.VPERM2F128 — Permute Floating-Point Values

VPERM2F128
CASE IMM8[1:0] of
0: DEST[127:0]  SRC1[127:0]
1: DEST[127:0]  SRC1[255:128]
2: DEST[127:0]  SRC2[127:0]
3: DEST[127:0]  SRC2[255:128]
ESAC
CASE IMM8[5:4] of
0: DEST[255:128]  SRC1[127:0]
1: DEST[255:128]  SRC1[255:128]
2: DEST[255:128]  SRC2[127:0]
3: DEST[255:128]  SRC2[255:128]
ESAC
IF (imm8[3])
DEST[127:0]  0
FI
IF (imm8[7])
DEST[VLMAX-1:128]  0
F