libavcodec/ppc/gmc_altivec.c

   1 /*
   2  * GMC (Global Motion Compensation)
   3  * AltiVec-enabled
   4  * Copyright (c) 2003 Romain Dolbeau <romain@dolbeau.org>
   5  *
   6  * This file is part of FFmpeg.
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include "libavcodec/dsputil.h"
  24
  25 #include "gcc_fixes.h"
  26
  27 #include "dsputil_ppc.h"
  28 #include "util_altivec.h"
  29
  30 /*
  31   altivec-enhanced gmc1. ATM this code assume stride is a multiple of 8,
  32   to preserve proper dst alignment.
  33 */
  34 #define GMC1_PERF_COND (h==8)
  35 void gmc1_altivec(uint8_t *dst /* align 8 */, uint8_t *src /* align1 */, int stride, int h, int x16, int y16, int rounder)
  36 {
  37 POWERPC_PERF_DECLARE(altivec_gmc1_num, GMC1_PERF_COND);
  38     const DECLARE_ALIGNED_16(unsigned short, rounder_a[8]) =
  39       {rounder, rounder, rounder, rounder,
  40        rounder, rounder, rounder, rounder};
  41     const DECLARE_ALIGNED_16(unsigned short, ABCD[8]) =
  42       {
  43         (16-x16)*(16-y16), /* A */
  44         (   x16)*(16-y16), /* B */
  45         (16-x16)*(   y16), /* C */
  46         (   x16)*(   y16), /* D */
  47         0, 0, 0, 0         /* padding */
  48       };
  49     register const vector unsigned char vczero = (const vector unsigned char)vec_splat_u8(0);
  50     register const vector unsigned short vcsr8 = (const vector unsigned short)vec_splat_u16(8);
  51     register vector unsigned char dstv, dstv2, src_0, src_1, srcvA, srcvB, srcvC, srcvD;
  52     register vector unsigned short Av, Bv, Cv, Dv, rounderV, tempA, tempB, tempC, tempD;
  53     int i;
  54     unsigned long dst_odd = (unsigned long)dst & 0x0000000F;
  55     unsigned long src_really_odd = (unsigned long)src & 0x0000000F;
  56
  57
  58 POWERPC_PERF_START_COUNT(altivec_gmc1_num, GMC1_PERF_COND);
  59
  60     tempA = vec_ld(0, (unsigned short*)ABCD);
  61     Av = vec_splat(tempA, 0);
  62     Bv = vec_splat(tempA, 1);
  63     Cv = vec_splat(tempA, 2);
  64     Dv = vec_splat(tempA, 3);
  65
  66     rounderV = vec_ld(0, (unsigned short*)rounder_a);
  67
  68     // we'll be able to pick-up our 9 char elements
  69     // at src from those 32 bytes
  70     // we load the first batch here, as inside the loop
  71     // we can re-use 'src+stride' from one iteration
  72     // as the 'src' of the next.
  73     src_0 = vec_ld(0, src);
  74     src_1 = vec_ld(16, src);
  75     srcvA = vec_perm(src_0, src_1, vec_lvsl(0, src));
  76
  77     if (src_really_odd != 0x0000000F)
  78     { // if src & 0xF == 0xF, then (src+1) is properly aligned on the second vector.
  79       srcvB = vec_perm(src_0, src_1, vec_lvsl(1, src));
  80     }
  81     else
  82     {
  83       srcvB = src_1;
  84     }
  85     srcvA = vec_mergeh(vczero, srcvA);
  86     srcvB = vec_mergeh(vczero, srcvB);
  87
  88     for(i=0; i<h; i++)
  89     {
  90       dst_odd = (unsigned long)dst & 0x0000000F;
  91       src_really_odd = (((unsigned long)src) + stride) & 0x0000000F;
  92
  93       dstv = vec_ld(0, dst);
  94
  95       // we we'll be able to pick-up our 9 char elements
  96       // at src + stride from those 32 bytes
  97       // then reuse the resulting 2 vectors srvcC and srcvD
  98       // as the next srcvA and srcvB
  99       src_0 = vec_ld(stride + 0, src);
 100       src_1 = vec_ld(stride + 16, src);
 101       srcvC = vec_perm(src_0, src_1, vec_lvsl(stride + 0, src));
 102
 103       if (src_really_odd != 0x0000000F)
 104       { // if src & 0xF == 0xF, then (src+1) is properly aligned on the second vector.
 105         srcvD = vec_perm(src_0, src_1, vec_lvsl(stride + 1, src));
 106       }
 107       else
 108       {
 109         srcvD = src_1;
 110       }
 111
 112       srcvC = vec_mergeh(vczero, srcvC);
 113       srcvD = vec_mergeh(vczero, srcvD);
 114
 115
 116       // OK, now we (finally) do the math :-)
 117       // those four instructions replaces 32 int muls & 32 int adds.
 118       // isn't AltiVec nice ?
 119       tempA = vec_mladd((vector unsigned short)srcvA, Av, rounderV);
 120       tempB = vec_mladd((vector unsigned short)srcvB, Bv, tempA);
 121       tempC = vec_mladd((vector unsigned short)srcvC, Cv, tempB);
 122       tempD = vec_mladd((vector unsigned short)srcvD, Dv, tempC);
 123
 124       srcvA = srcvC;
 125       srcvB = srcvD;
 126
 127       tempD = vec_sr(tempD, vcsr8);
 128
 129       dstv2 = vec_pack(tempD, (vector unsigned short)vczero);
 130
 131       if (dst_odd)
 132       {
 133         dstv2 = vec_perm(dstv, dstv2, vcprm(0,1,s0,s1));
 134       }
 135       else
 136       {
 137         dstv2 = vec_perm(dstv, dstv2, vcprm(s0,s1,2,3));
 138       }
 139
 140       vec_st(dstv2, 0, dst);
 141
 142       dst += stride;
 143       src += stride;
 144     }
 145
 146 POWERPC_PERF_STOP_COUNT(altivec_gmc1_num, GMC1_PERF_COND);
 147 }