gstreamer/gst/videomixer/blend_mmx.h

#ifdef A32
static inline void
NAME_BLEND (guint8 * dest, const guint8 * src, gint src_height, gint src_width,
    gint src_stride, gint dest_stride, guint s_alpha)
{
  gint i;
  gint src_add = src_stride - (4 * src_width);
  gint dest_add = dest_stride - (4 * src_width);

  for (i = 0; i < src_height; i++) {
    /*      (P1 * (256 - A) + (P2 * A)) / 256
     * =>   (P1 * 256 - P1 * A + P2 * A) / 256
     * =>   (P1 * 256 + A * (P2 - P1) / 256
     * =>   P1 + (A * (P2 - P1)) / 256
     */
    /* *INDENT-OFF* */
    __asm__ __volatile__ (
        " pcmpeqd    %%mm5 ,   %%mm5   \n\t"   /* mm5 = 0xffff... */
#if A_OFF == 0
        " psrld        $24 ,   %%mm5   \n\t"   /* mm5 = 00 00 00 ff 00 00 00 ff, selector for alpha */
#else
        " pslld        $24 ,   %%mm5   \n\t"   /* mm5 = ff 00 00 00 ff 00 00 00, selector for alpha */
#endif
        " mov           %4 ,   %%eax   \n\t"   /* eax = s_alpha */
        " movd       %%eax ,   %%mm6   \n\t"   /* mm6 = s_alpha */
        " punpckldq  %%mm6 ,   %%mm6   \n\t"   /* mm6 = 00 00 00 aa 00 00 00 aa, alpha scale factor */

        " movl          %5 ,   %%ecx   \n\t"   /* ecx = src_width */
        " test          $1 ,   %%ecx   \n\t"   /* check odd pixel */
        " je                      1f   \n\t"

        /* do odd pixel */
        " movd        (%2) ,   %%mm2   \n\t"   /* mm2 = src,  00 00 00 00 sv su sy sa */
        " movd        (%3) ,   %%mm1   \n\t"   /* mm1 = dest, 00 00 00 00 dv du dy da */
        " movq       %%mm2 ,   %%mm0   \n\t"
        " punpcklbw  %%mm7 ,   %%mm2   \n\t"   /* mm2 = 00 sv 00 su 00 sy 00 sa */
        " pand       %%mm5 ,   %%mm0   \n\t"   /* mm0 = 00 00 00 00 00 00 00 sa, get alpha component  */
#if A_OFF != 0
        " psrld        $24 ,   %%mm0   \n\t"
#endif
        " punpcklbw  %%mm7 ,   %%mm1   \n\t"   /* mm1 = 00 dv 00 du 00 dy 00 da */
        " pmullw     %%mm6 ,   %%mm0   \n\t"   /* mult with scale */
        " psubw      %%mm1 ,   %%mm2   \n\t"   /* mm2 = mm2 - mm1 */
        " punpcklwd  %%mm0 ,   %%mm0   \n\t"
        " punpckldq  %%mm0 ,   %%mm0   \n\t"   /* mm0 == 00 aa 00 aa 00 aa 00 aa */
        " psrlw         $8 ,   %%mm0   \n\t"
        " pmullw     %%mm0 ,   %%mm2   \n\t"   /* mm2 == a * mm2 */
        " psllw         $8 ,   %%mm1   \n\t"   /* scale up */
        " paddw      %%mm1 ,   %%mm2   \n\t"   /* mm2 == mm2 + mm1 */
        " psrlw         $8 ,   %%mm2   \n\t"   /* scale down */
        " por        %%mm5 ,   %%mm2   \n\t"   /* set alpha to ff */
        " packuswb   %%mm2 ,   %%mm2   \n\t" 
        " movd       %%mm2 ,    (%3)   \n\t"   /* dest = mm1 */
        " add           $4 ,     %1    \n\t"
        " add           $4 ,     %0    \n\t"

        "1:                            \n\t"
        " sar           $1 ,   %%ecx   \n\t"   /* prepare for 2 pixel per loop */
        " cmp           $0 ,   %%ecx   \n\t"
        " je                      3f   \n\t"
        "2:                            \n\t"

        /* do even pixels */
        " movq        (%2) ,   %%mm2   \n\t"   /* mm2 = src,  sv1 su1 sy1 sa1  sv0 su0 sy0 sa0 */
        " movq        (%3) ,   %%mm1   \n\t"   /* mm1 = dest, dv1 du1 dy1 da1  dv0 du0 dy0 da0 */
        " movq       %%mm2 ,   %%mm4   \n\t"
        " movq       %%mm1 ,   %%mm3   \n\t"
        " movq       %%mm2 ,   %%mm0   \n\t"   /* copy for doing the alpha */

        " pxor       %%mm7 ,   %%mm7   \n\t"  
        " punpcklbw  %%mm7 ,   %%mm2   \n\t"   /* mm2 = 00 sv0  00 su0  00 sy0  00 sa0 */
        " punpckhbw  %%mm7 ,   %%mm4   \n\t"   /* mm4 = 00 sv1  00 su1  00 sy1  00 sa1 */
        " punpcklbw  %%mm7 ,   %%mm1   \n\t"   /* mm1 = 00 dv0  00 du0  00 dy0  00 da0 */
        " punpckhbw  %%mm7 ,   %%mm3   \n\t"   /* mm2 = 00 dv1  00 du1  00 dy1  00 da1 */

        " pand       %%mm5 ,   %%mm0   \n\t"   /* mm0 = 00 00 00 sa1  00 00 00 sa0 */
#if A_OFF != 0
        " psrld        $24 ,   %%mm0   \n\t"
#endif
        " psubw      %%mm1 ,   %%mm2   \n\t"   /* mm2 = mm2 - mm1 */
        " pmullw     %%mm6 ,   %%mm0   \n\t"   /* mult with scale */
        " psubw      %%mm3 ,   %%mm4   \n\t"   /* mm4 = mm4 - mm3 */
        " psrlw         $8 ,   %%mm0   \n\t"   /* scale back */
        " movq       %%mm0 ,   %%mm7   \n\t"   /* save copy */
        " punpcklwd  %%mm0 ,   %%mm0   \n\t"   /* mm0 = 00 00   00 00   00 aa0  00 aa0 */
        " punpckhwd  %%mm7 ,   %%mm7   \n\t"   /* mm7 = 00 00   00 00   00 aa1  00 aa1 */
        " punpckldq  %%mm0 ,   %%mm0   \n\t"   /* mm0 = 00 aa0  00 aa0  00 aa0  00 aa0 */
        " punpckldq  %%mm7 ,   %%mm7   \n\t"   /* mm7 = 00 aa1  00 aa1  00 aa1  00 aa1 */

        " pmullw     %%mm0 ,   %%mm2   \n\t"   /* mm2 == aa * mm2 */
        " pmullw     %%mm7 ,   %%mm4   \n\t"   /* mm2 == aa * mm2 */
        " psllw         $8 ,   %%mm1   \n\t"
        " psllw         $8 ,   %%mm3   \n\t"
        " paddw      %%mm1 ,   %%mm2   \n\t"   /* mm2 == mm2 + mm1 */
        " paddw      %%mm3 ,   %%mm4   \n\t"   /* mm2 == mm2 + mm1 */

        " psrlw         $8 ,   %%mm2   \n\t"
        " psrlw         $8 ,   %%mm4   \n\t"
        " packuswb   %%mm4 ,   %%mm2   \n\t"
        " por        %%mm5 ,   %%mm2   \n\t"   /* set alpha to ff */
        " movq       %%mm2 ,    (%3)   \n\t"

        " add           $8 ,     %1    \n\t"
        " add           $8 ,     %0    \n\t"
        " dec           %%ecx          \n\t"
        " jne                     2b   \n\t"

        "3:                            \n\t"
        :"=r" (src), "=r" (dest)
        :"0" (src), "1" (dest), "m" (s_alpha), "m" (src_width)
        :"%eax", "%ecx", "memory",
         "st", "st(1)", "st(2)", "st(3)", "st(4)", "st(5)", "st(6)", "st(7)"
#ifdef __MMX__
        , "mm0", "mm1", "mm2", "mm4", "mm3", "mm5", "mm6", "mm7"
#endif
    );
      /* *INDENT-ON* */
    src += src_add;
    dest += dest_add;
  }
  __asm__ __volatile__ ("emms");
}
#endif