GAS illegally encodes FMA4.

[NEGISHI, Kiyoshi]

Hi,

I believe that encoding old INTEL AVX FMA and AMD FMA4 is different  
specifications.

in gas format:
    vfmaddpd %xmm4,%xmm6,%xmm2,%xmm7

operand order is
    vfmaddpd src3, src2, src1, dest

that's right?

gas encoding this is
    c4 e3 c9 69 fc 20

this means
    ModRM.reg=%xmm7 VEX.vvvv=%xmm6 ModRM.r/m=%xmm4 imm8[7:4]=%xmm2


This is AVX FMA encoding because src1=imm8[7:4].

The AMD FMA4 encoding is src1=VEX.vvvv, so right:
    c4 e3 e9 69 fc 60

    ModRM.reg=%xmm7 VEX.vvvv=%xmm2 ModRM.r/m=%xmm4 imm8[7:4]=%xmm6


Negishi.