The Tor Browser: media/libtheora/lib/x86/mmxloop.h@b8a032363ba2 (annotated)

media/libtheora/lib/x86/mmxloop.h@b8a032363ba2 (annotated)

media/libtheora/lib/x86/mmxloop.h

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 #if !defined(_x86_mmxloop_H)
 # define _x86_mmxloop_H (1)
 # include <stddef.h>
 # include "x86int.h"
 #if defined(OC_X86_ASM)
 /*On entry, mm0={a0,...,a7}, mm1={b0,...,b7}, mm2={c0,...,c7}, mm3={d0,...d7}.
   On exit, mm1={b0+lflim(R_0,L),...,b7+lflim(R_7,L)} and
    mm2={c0-lflim(R_0,L),...,c7-lflim(R_7,L)}; mm0 and mm3 are clobbered.*/
 #define OC_LOOP_FILTER8_MMX \
   "#OC_LOOP_FILTER8_MMX\n\t" \
   /*mm7=0*/ \
   "pxor %%mm7,%%mm7\n\t" \
   /*mm6:mm0={a0,...,a7}*/ \
   "movq %%mm0,%%mm6\n\t" \
   "punpcklbw %%mm7,%%mm0\n\t" \
   "punpckhbw %%mm7,%%mm6\n\t" \
   /*mm3:mm5={d0,...,d7}*/ \
   "movq %%mm3,%%mm5\n\t" \
   "punpcklbw %%mm7,%%mm3\n\t" \
   "punpckhbw %%mm7,%%mm5\n\t" \
   /*mm6:mm0={a0-d0,...,a7-d7}*/ \
   "psubw %%mm3,%%mm0\n\t" \
   "psubw %%mm5,%%mm6\n\t" \
   /*mm3:mm1={b0,...,b7}*/ \
   "movq %%mm1,%%mm3\n\t" \
   "punpcklbw %%mm7,%%mm1\n\t" \
   "movq %%mm2,%%mm4\n\t" \
   "punpckhbw %%mm7,%%mm3\n\t" \
   /*mm5:mm4={c0,...,c7}*/ \
   "movq %%mm2,%%mm5\n\t" \
   "punpcklbw %%mm7,%%mm4\n\t" \
   "punpckhbw %%mm7,%%mm5\n\t" \
   /*mm7={3}x4 \
     mm5:mm4={c0-b0,...,c7-b7}*/ \
   "pcmpeqw %%mm7,%%mm7\n\t" \
   "psubw %%mm1,%%mm4\n\t" \
   "psrlw $14,%%mm7\n\t" \
   "psubw %%mm3,%%mm5\n\t" \
   /*Scale by 3.*/ \
   "pmullw %%mm7,%%mm4\n\t" \
   "pmullw %%mm7,%%mm5\n\t" \
   /*mm7={4}x4 \
     mm5:mm4=f={a0-d0+3*(c0-b0),...,a7-d7+3*(c7-b7)}*/ \
   "psrlw $1,%%mm7\n\t" \
   "paddw %%mm0,%%mm4\n\t" \
   "psllw $2,%%mm7\n\t" \
   "movq (%[ll]),%%mm0\n\t" \
   "paddw %%mm6,%%mm5\n\t" \
   /*R_i has the range [-127,128], so we compute -R_i instead. \
     mm4=-R_i=-(f+4>>3)=0xFF^(f-4>>3)*/ \
   "psubw %%mm7,%%mm4\n\t" \
   "psubw %%mm7,%%mm5\n\t" \
   "psraw $3,%%mm4\n\t" \
   "psraw $3,%%mm5\n\t" \
   "pcmpeqb %%mm7,%%mm7\n\t" \
   "packsswb %%mm5,%%mm4\n\t" \
   "pxor %%mm6,%%mm6\n\t" \
   "pxor %%mm7,%%mm4\n\t" \
   "packuswb %%mm3,%%mm1\n\t" \
   /*Now compute lflim of -mm4 cf. Section 7.10 of the sepc.*/ \
   /*There's no unsigned byte+signed byte with unsigned saturation op code, so \
      we have to split things by sign (the other option is to work in 16 bits, \
      but working in 8 bits gives much better parallelism). \
     We compute abs(R_i), but save a mask of which terms were negative in mm6. \
     Then we compute mm4=abs(lflim(R_i,L))=min(abs(R_i),max(2*L-abs(R_i),0)). \
     Finally, we split mm4 into positive and negative pieces using the mask in \
      mm6, and add and subtract them as appropriate.*/ \
   /*mm4=abs(-R_i)*/ \
   /*mm7=255-2*L*/ \
   "pcmpgtb %%mm4,%%mm6\n\t" \
   "psubb %%mm0,%%mm7\n\t" \
   "pxor %%mm6,%%mm4\n\t" \
   "psubb %%mm0,%%mm7\n\t" \
   "psubb %%mm6,%%mm4\n\t" \
   /*mm7=255-max(2*L-abs(R_i),0)*/ \
   "paddusb %%mm4,%%mm7\n\t" \
   /*mm4=min(abs(R_i),max(2*L-abs(R_i),0))*/ \
   "paddusb %%mm7,%%mm4\n\t" \
   "psubusb %%mm7,%%mm4\n\t" \
   /*Now split mm4 by the original sign of -R_i.*/ \
   "movq %%mm4,%%mm5\n\t" \
   "pand %%mm6,%%mm4\n\t" \
   "pandn %%mm5,%%mm6\n\t" \
   /*mm1={b0+lflim(R_0,L),...,b7+lflim(R_7,L)}*/ \
   /*mm2={c0-lflim(R_0,L),...,c7-lflim(R_7,L)}*/ \
   "paddusb %%mm4,%%mm1\n\t" \
   "psubusb %%mm4,%%mm2\n\t" \
   "psubusb %%mm6,%%mm1\n\t" \
   "paddusb %%mm6,%%mm2\n\t" \
 /*On entry, mm0={a0,...,a7}, mm1={b0,...,b7}, mm2={c0,...,c7}, mm3={d0,...d7}.
   On exit, mm1={b0+lflim(R_0,L),...,b7+lflim(R_7,L)} and
    mm2={c0-lflim(R_0,L),...,c7-lflim(R_7,L)}.
   All other MMX registers are clobbered.*/
 #define OC_LOOP_FILTER8_MMXEXT \
   "#OC_LOOP_FILTER8_MMXEXT\n\t" \
   /*R_i=(a_i-3*b_i+3*c_i-d_i+4>>3) has the range [-127,128], so we compute \
      -R_i=(-a_i+3*b_i-3*c_i+d_i+3>>3) instead.*/ \
   /*This first part is based on the transformation \
       f = -(3*(c-b)+a-d+4>>3) \
         = -(3*(c+255-b)+(a+255-d)+4-1020>>3) \
         = -(3*(c+~b)+(a+~d)-1016>>3) \
         = 127-(3*(c+~b)+(a+~d)>>3) \
         = 128+~(3*(c+~b)+(a+~d)>>3) (mod 256). \
     Although pavgb(a,b) = (a+b+1>>1) (biased up), we rely heavily on the \
      fact that ~pavgb(~a,~b) = (a+b>>1) (biased down). \
     Using this, the last expression above can be computed in 8 bits of working \
      precision via: \
       u = ~pavgb(~b,c); \
       v = pavgb(b,~c); \
       This mask is 0 or 0xFF, and controls whether t is biased up or down: \
       m = u-v; \
       t = m^pavgb(m^~a,m^d); \
       f = 128+pavgb(pavgb(t,u),v); \
     This required some careful analysis to ensure that carries are propagated \
      correctly in all cases, but has been checked exhaustively.*/ \
   /*input (a, b, c, d, ., ., ., .)*/ \
   /*ff=0xFF; \
     u=b; \
     v=c; \
     ll=255-2*L;*/ \
   "pcmpeqb %%mm7,%%mm7\n\t" \
   "movq %%mm1,%%mm4\n\t" \
   "movq %%mm2,%%mm5\n\t" \
   "movq (%[ll]),%%mm6\n\t" \
   /*allocated u, v, ll, ff: (a, b, c, d, u, v, ll, ff)*/ \
   /*u^=ff; \
     v^=ff;*/ \
   "pxor %%mm7,%%mm4\n\t" \
   "pxor %%mm7,%%mm5\n\t" \
   /*allocated ll: (a, b, c, d, u, v, ll, ff)*/ \
   /*u=pavgb(u,c); \
     v=pavgb(v,b);*/ \
   "pavgb %%mm2,%%mm4\n\t" \
   "pavgb %%mm1,%%mm5\n\t" \
   /*u^=ff; \
     a^=ff;*/ \
   "pxor %%mm7,%%mm4\n\t" \
   "pxor %%mm7,%%mm0\n\t" \
   /*m=u-v;*/ \
   "psubb %%mm5,%%mm4\n\t" \
   /*freed u, allocated m: (a, b, c, d, m, v, ll, ff)*/ \
   /*a^=m; \
     d^=m;*/ \
   "pxor %%mm4,%%mm0\n\t" \
   "pxor %%mm4,%%mm3\n\t" \
   /*t=pavgb(a,d);*/ \
   "pavgb %%mm3,%%mm0\n\t" \
   "psllw $7,%%mm7\n\t" \
   /*freed a, d, ff, allocated t, of: (t, b, c, ., m, v, ll, of)*/ \
   /*t^=m; \
     u=m+v;*/ \
   "pxor %%mm4,%%mm0\n\t" \
   "paddb %%mm5,%%mm4\n\t" \
   /*freed t, m, allocated f, u: (f, b, c, ., u, v, ll, of)*/ \
   /*f=pavgb(f,u); \
     of=128;*/ \
   "pavgb %%mm4,%%mm0\n\t" \
   "packsswb %%mm7,%%mm7\n\t" \
   /*freed u, ff, allocated ll: (f, b, c, ., ll, v, ll, of)*/ \
   /*f=pavgb(f,v);*/ \
   "pavgb %%mm5,%%mm0\n\t" \
   "movq %%mm7,%%mm3\n\t" \
   "movq %%mm6,%%mm4\n\t" \
   /*freed v, allocated of: (f, b, c, of, ll, ., ll, of)*/ \
   /*Now compute lflim of R_i=-(128+mm0) cf. Section 7.10 of the sepc.*/ \
   /*There's no unsigned byte+signed byte with unsigned saturation op code, so \
      we have to split things by sign (the other option is to work in 16 bits, \
      but staying in 8 bits gives much better parallelism).*/ \
   /*Instead of adding the offset of 128 in mm3, we use it to split mm0. \
     This is the same number of instructions as computing a mask and splitting \
      after the lflim computation, but has shorter dependency chains.*/ \
   /*mm0=R_i<0?-R_i:0 (denoted abs(R_i<0))\
     mm3=R_i>0?R_i:0* (denoted abs(R_i>0))*/ \
   "psubusb %%mm0,%%mm3\n\t" \
   "psubusb %%mm7,%%mm0\n\t" \
   /*mm6=255-max(2*L-abs(R_i<0),0) \
     mm4=255-max(2*L-abs(R_i>0),0)*/ \
   "paddusb %%mm3,%%mm4\n\t" \
   "paddusb %%mm0,%%mm6\n\t" \
   /*mm0=min(abs(R_i<0),max(2*L-abs(R_i<0),0)) \
     mm3=min(abs(R_i>0),max(2*L-abs(R_i>0),0))*/ \
   "paddusb %%mm4,%%mm3\n\t" \
   "paddusb %%mm6,%%mm0\n\t" \
   "psubusb %%mm4,%%mm3\n\t" \
   "psubusb %%mm6,%%mm0\n\t" \
   /*mm1={b0+lflim(R_0,L),...,b7+lflim(R_7,L)}*/ \
   /*mm2={c0-lflim(R_0,L),...,c7-lflim(R_7,L)}*/ \
   "paddusb %%mm3,%%mm1\n\t" \
   "psubusb %%mm3,%%mm2\n\t" \
   "psubusb %%mm0,%%mm1\n\t" \
   "paddusb %%mm0,%%mm2\n\t" \
 #define OC_LOOP_FILTER_V(_filter,_pix,_ystride,_ll) \
   do{ \
     ptrdiff_t ystride3__; \
     __asm__ __volatile__( \
       /*mm0={a0,...,a7}*/ \
       "movq (%[pix]),%%mm0\n\t" \
       /*ystride3=_ystride*3*/ \
       "lea (%[ystride],%[ystride],2),%[ystride3]\n\t" \
       /*mm3={d0,...,d7}*/ \
       "movq (%[pix],%[ystride3]),%%mm3\n\t" \
       /*mm1={b0,...,b7}*/ \
       "movq (%[pix],%[ystride]),%%mm1\n\t" \
       /*mm2={c0,...,c7}*/ \
       "movq (%[pix],%[ystride],2),%%mm2\n\t" \
       _filter \
       /*Write it back out.*/ \
       "movq %%mm1,(%[pix],%[ystride])\n\t" \
       "movq %%mm2,(%[pix],%[ystride],2)\n\t" \
       :[ystride3]"=&r"(ystride3__) \
       :[pix]"r"(_pix-_ystride*2),[ystride]"r"((ptrdiff_t)(_ystride)), \
        [ll]"r"(_ll) \
       :"memory" \
     ); \
   } \
   while(0)
 #define OC_LOOP_FILTER_H(_filter,_pix,_ystride,_ll) \
   do{ \
     unsigned char *pix__; \
     ptrdiff_t      ystride3__; \
     ptrdiff_t      d__; \
     pix__=(_pix)-2; \
     __asm__ __volatile__( \
       /*x x x x d0 c0 b0 a0*/ \
       "movd (%[pix]),%%mm0\n\t" \
       /*x x x x d1 c1 b1 a1*/ \
       "movd (%[pix],%[ystride]),%%mm1\n\t" \
       /*ystride3=_ystride*3*/ \
       "lea (%[ystride],%[ystride],2),%[ystride3]\n\t" \
       /*x x x x d2 c2 b2 a2*/ \
       "movd (%[pix],%[ystride],2),%%mm2\n\t" \
       /*x x x x d3 c3 b3 a3*/ \
       "lea (%[pix],%[ystride],4),%[d]\n\t" \
       "movd (%[pix],%[ystride3]),%%mm3\n\t" \
       /*x x x x d4 c4 b4 a4*/ \
       "movd (%[d]),%%mm4\n\t" \
       /*x x x x d5 c5 b5 a5*/ \
       "movd (%[d],%[ystride]),%%mm5\n\t" \
       /*x x x x d6 c6 b6 a6*/ \
       "movd (%[d],%[ystride],2),%%mm6\n\t" \
       /*x x x x d7 c7 b7 a7*/ \
       "movd (%[d],%[ystride3]),%%mm7\n\t" \
       /*mm0=d1 d0 c1 c0 b1 b0 a1 a0*/ \
       "punpcklbw %%mm1,%%mm0\n\t" \
       /*mm2=d3 d2 c3 c2 b3 b2 a3 a2*/ \
       "punpcklbw %%mm3,%%mm2\n\t" \
       /*mm3=d1 d0 c1 c0 b1 b0 a1 a0*/ \
       "movq %%mm0,%%mm3\n\t" \
       /*mm0=b3 b2 b1 b0 a3 a2 a1 a0*/ \
       "punpcklwd %%mm2,%%mm0\n\t" \
       /*mm3=d3 d2 d1 d0 c3 c2 c1 c0*/ \
       "punpckhwd %%mm2,%%mm3\n\t" \
       /*mm1=b3 b2 b1 b0 a3 a2 a1 a0*/ \
       "movq %%mm0,%%mm1\n\t" \
       /*mm4=d5 d4 c5 c4 b5 b4 a5 a4*/ \
       "punpcklbw %%mm5,%%mm4\n\t" \
       /*mm6=d7 d6 c7 c6 b7 b6 a7 a6*/ \
       "punpcklbw %%mm7,%%mm6\n\t" \
       /*mm5=d5 d4 c5 c4 b5 b4 a5 a4*/ \
       "movq %%mm4,%%mm5\n\t" \
       /*mm4=b7 b6 b5 b4 a7 a6 a5 a4*/ \
       "punpcklwd %%mm6,%%mm4\n\t" \
       /*mm5=d7 d6 d5 d4 c7 c6 c5 c4*/ \
       "punpckhwd %%mm6,%%mm5\n\t" \
       /*mm2=d3 d2 d1 d0 c3 c2 c1 c0*/ \
       "movq %%mm3,%%mm2\n\t" \
       /*mm0=a7 a6 a5 a4 a3 a2 a1 a0*/ \
       "punpckldq %%mm4,%%mm0\n\t" \
       /*mm1=b7 b6 b5 b4 b3 b2 b1 b0*/ \
       "punpckhdq %%mm4,%%mm1\n\t" \
       /*mm2=c7 c6 c5 c4 c3 c2 c1 c0*/ \
       "punpckldq %%mm5,%%mm2\n\t" \
       /*mm3=d7 d6 d5 d4 d3 d2 d1 d0*/ \
       "punpckhdq %%mm5,%%mm3\n\t" \
       _filter \
       /*mm2={b0+R_0'',...,b7+R_7''}*/ \
       "movq %%mm1,%%mm0\n\t" \
       /*mm1={b0+R_0'',c0-R_0'',...,b3+R_3'',c3-R_3''}*/ \
       "punpcklbw %%mm2,%%mm1\n\t" \
       /*mm2={b4+R_4'',c4-R_4'',...,b7+R_7'',c7-R_7''}*/ \
       "punpckhbw %%mm2,%%mm0\n\t" \
       /*[d]=c1 b1 c0 b0*/ \
       "movd %%mm1,%[d]\n\t" \
       "movw %w[d],1(%[pix])\n\t" \
       "psrlq $32,%%mm1\n\t" \
       "shr $16,%[d]\n\t" \
       "movw %w[d],1(%[pix],%[ystride])\n\t" \
       /*[d]=c3 b3 c2 b2*/ \
       "movd %%mm1,%[d]\n\t" \
       "movw %w[d],1(%[pix],%[ystride],2)\n\t" \
       "shr $16,%[d]\n\t" \
       "movw %w[d],1(%[pix],%[ystride3])\n\t" \
       "lea (%[pix],%[ystride],4),%[pix]\n\t" \
       /*[d]=c5 b5 c4 b4*/ \
       "movd %%mm0,%[d]\n\t" \
       "movw %w[d],1(%[pix])\n\t" \
       "psrlq $32,%%mm0\n\t" \
       "shr $16,%[d]\n\t" \
       "movw %w[d],1(%[pix],%[ystride])\n\t" \
       /*[d]=c7 b7 c6 b6*/ \
       "movd %%mm0,%[d]\n\t" \
       "movw %w[d],1(%[pix],%[ystride],2)\n\t" \
       "shr $16,%[d]\n\t" \
       "movw %w[d],1(%[pix],%[ystride3])\n\t" \
       :[pix]"+r"(pix__),[ystride3]"=&r"(ystride3__),[d]"=&r"(d__) \
       :[ystride]"r"((ptrdiff_t)(_ystride)),[ll]"r"(_ll) \
       :"memory" \
     ); \
   } \
   while(0)
 # endif
 #endif

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media/libtheora/lib/x86/mmxloop.h@b8a032363ba2 (annotated)

media/libtheora/lib/x86/mmxloop.h