Assembly x64 Intro - MMX 4x4W Transpose

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; pOut mm1, mm4, mm5, mm3
%macro MMX_Trans4x4W 5
    MMX_XSwap wd, %1, %2, %5
    MMX_XSwap wd, %3, %4, %2
    MMX_XSwap dq, %1, %3, %4
    MMX_XSwap dq, %5, %2, %3
%endmacro

%macro MMX_XSwap 4
    movq        %4, %2
    punpckh%1   %4, %3
    punpckl%1   %2, %3
%endmacro

MMX_Trans4x4W mm0, mm1, mm2, mm3, mm4

Here, assume, mm0 = a3a2a1a0, mm1 = b3b2b1b0, mm2 = c3c2c1c0, mm3 = d3d2d1d0 (4个16bit)

MMX_Trans4x4W mm0, mm1, mm2, mm3, mm4 将使得

mm0 = d0c0b0a0, mm3 = d1c1b1a1, mm4 = d2c2b2a2, mm2 = d3c3b3a3

上述展开如下：

MMX_XSwap wd, mm0, mm1, mm4 =>

movq mm4, mm0 => mm4 = mm0 = a3a2a1a0

punpckhwd mm4, mm1 => mm4 = b3a3b2a2

punpcklwd mm0, mm1 => mm0 = b1a1b0a0

MMX_XSwap wd, mm2, mm3, mm1 =>

movq mm1, mm2 => mm1 = mm2 = c3c2c1c0

punpckhwd mm1, mm3 => mm1 = d3c3d2c2

punpcklwd mm2, mm3 => mm2 = d1c1d0c0

MMX_XSwap dq, mm0, mm2, mm3 =>

movq mm3, mm0 => mm3 = mm0 = b1a1b0a0

punpckhdq mm3, mm2 => mm3 = d1c1b1a1

punpckldq mm0, mm2 => mm0 = d0c0b0a0

MMX_XSwap dq, mm4, mm1, mm2 =>

movq mm2, mm4 => mm2 = mm4 = b3a3b2a2

punpckhdq mm2, mm1 => mm2 = d3c3b3a3

punpckldq mm4, mm1 => mm4 = d2c2b2a2

=> mm0 = d0c0b0a0, mm3 = d1c1b1a1, mm4 = d2c2b2a2, mm2 = d3c3b3a3

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