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 library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include "../dsputil.h"
  22
  23 #include "dsputil_altivec.h"
  24
  25 /*
  26   altivec-enhanced gmc1. ATM this code assume stride is a multiple of 8,
  27   to preserve proper dst alignement.
  28 */
  29 void gmc1_altivec(UINT8 *dst /* align 8 */, UINT8 *src /* align1 */, int stride, int h, int x16, int y16, int rounder)
  30 {
  31 POWERPC_TBL_DECLARE(altivec_gmc1_num, h == 8);
  32 #ifdef ALTIVEC_USE_REFERENCE_C_CODE
  33     const int A=(16-x16)*(16-y16);
  34     const int B=(   x16)*(16-y16);
  35     const int C=(16-x16)*(   y16);
  36     const int D=(   x16)*(   y16);
  37     int i;
  38
  39 POWERPC_TBL_START_COUNT(altivec_gmc1_num, h == 8);
  40
  41     for(i=0; i<h; i++)
  42     {
  43         dst[0]= (A*src[0] + B*src[1] + C*src[stride+0] + D*src[stride+1] + rounder)>>8;
  44         dst[1]= (A*src[1] + B*src[2] + C*src[stride+1] + D*src[stride+2] + rounder)>>8;
  45         dst[2]= (A*src[2] + B*src[3] + C*src[stride+2] + D*src[stride+3] + rounder)>>8;
  46         dst[3]= (A*src[3] + B*src[4] + C*src[stride+3] + D*src[stride+4] + rounder)>>8;
  47         dst[4]= (A*src[4] + B*src[5] + C*src[stride+4] + D*src[stride+5] + rounder)>>8;
  48         dst[5]= (A*src[5] + B*src[6] + C*src[stride+5] + D*src[stride+6] + rounder)>>8;
  49         dst[6]= (A*src[6] + B*src[7] + C*src[stride+6] + D*src[stride+7] + rounder)>>8;
  50         dst[7]= (A*src[7] + B*src[8] + C*src[stride+7] + D*src[stride+8] + rounder)>>8;
  51         dst+= stride;
  52         src+= stride;
  53     }
  54
  55 POWERPC_TBL_STOP_COUNT(altivec_gmc1_num, h == 8);
  56
  57 #else /* ALTIVEC_USE_REFERENCE_C_CODE */
  58     const unsigned short __attribute__ ((aligned(16))) rounder_a[8] =
  59       {rounder, rounder, rounder, rounder,
  60        rounder, rounder, rounder, rounder};
  61     const unsigned short __attribute__ ((aligned(16))) ABCD[8] =
  62       {
  63         (16-x16)*(16-y16), /* A */
  64         (   x16)*(16-y16), /* B */
  65         (16-x16)*(   y16), /* C */
  66         (   x16)*(   y16), /* D */
  67         0, 0, 0, 0         /* padding */
  68       };
  69     register const vector unsigned char vczero = (const vector unsigned char)vec_splat_u8(0);
  70     register const vector unsigned short vcsr8 = (const vector unsigned short)vec_splat_u16(8);
  71     register vector unsigned char dstv, dstv2, src_0, src_1, srcvA, srcvB, srcvC, srcvD;
  72     register vector unsigned short Av, Bv, Cv, Dv, rounderV, tempA, tempB, tempC, tempD;
  73     int i;
  74     unsigned long dst_odd = (unsigned long)dst & 0x0000000F;
  75     unsigned long src_really_odd = (unsigned long)src & 0x0000000F;
  76
  77
  78 POWERPC_TBL_START_COUNT(altivec_gmc1_num, h == 8);
  79
  80     tempA = vec_ld(0, (unsigned short*)ABCD);
  81     Av = vec_splat(tempA, 0);
  82     Bv = vec_splat(tempA, 1);
  83     Cv = vec_splat(tempA, 2);
  84     Dv = vec_splat(tempA, 3);
  85
  86     rounderV = vec_ld(0, (unsigned short*)rounder_a);
  87
  88     // we'll be able to pick-up our 9 char elements
  89     // at src from those 32 bytes
  90     // we load the first batch here, as inside the loop
  91     // we can re-use 'src+stride' from one iteration
  92     // as the 'src' of the next.
  93     src_0 = vec_ld(0, src);
  94     src_1 = vec_ld(16, src);
  95     srcvA = vec_perm(src_0, src_1, vec_lvsl(0, src));
  96
  97     if (src_really_odd != 0x0000000F)
  98     { // if src & 0xF == 0xF, then (src+1) is properly aligned on the second vector.
  99       srcvB = vec_perm(src_0, src_1, vec_lvsl(1, src));
 100     }
 101     else
 102     {
 103       srcvB = src_1;
 104     }
 105     srcvA = vec_mergeh(vczero, srcvA);
 106     srcvB = vec_mergeh(vczero, srcvB);
 107
 108     for(i=0; i<h; i++)
 109     {
 110       dst_odd = (unsigned long)dst & 0x0000000F;
 111       src_really_odd = (((unsigned long)src) + stride) & 0x0000000F;
 112
 113       dstv = vec_ld(0, dst);
 114
 115       // we we'll be able to pick-up our 9 char elements
 116       // at src + stride from those 32 bytes
 117       // then reuse the resulting 2 vectors srvcC and srcvD
 118       // as the next srcvA and srcvB
 119       src_0 = vec_ld(stride + 0, src);
 120       src_1 = vec_ld(stride + 16, src);
 121       srcvC = vec_perm(src_0, src_1, vec_lvsl(stride + 0, src));
 122
 123       if (src_really_odd != 0x0000000F)
 124       { // if src & 0xF == 0xF, then (src+1) is properly aligned on the second vector.
 125         srcvD = vec_perm(src_0, src_1, vec_lvsl(stride + 1, src));
 126       }
 127       else
 128       {
 129         srcvD = src_1;
 130       }
 131
 132       srcvC = vec_mergeh(vczero, srcvC);
 133       srcvD = vec_mergeh(vczero, srcvD);
 134
 135
 136       // OK, now we (finally) do the math :-)
 137       // those four instructions replaces 32 int muls & 32 int adds.
 138       // isn't AltiVec nice ?
 139       tempA = vec_mladd((vector unsigned short)srcvA, Av, rounderV);
 140       tempB = vec_mladd((vector unsigned short)srcvB, Bv, tempA);
 141       tempC = vec_mladd((vector unsigned short)srcvC, Cv, tempB);
 142       tempD = vec_mladd((vector unsigned short)srcvD, Dv, tempC);
 143
 144       srcvA = srcvC;
 145       srcvB = srcvD;
 146
 147       tempD = vec_sr(tempD, vcsr8);
 148
 149       dstv2 = vec_pack(tempD, (vector unsigned short)vczero);
 150
 151       if (dst_odd)
 152       {
 153         dstv2 = vec_perm(dstv, dstv2, vcprm(0,1,s0,s1));
 154       }
 155       else
 156       {
 157         dstv2 = vec_perm(dstv, dstv2, vcprm(s0,s1,2,3));
 158       }
 159
 160       vec_st(dstv2, 0, dst);
 161
 162       dst += stride;
 163       src += stride;
 164     }
 165
 166 POWERPC_TBL_STOP_COUNT(altivec_gmc1_num, h == 8);
 167
 168 #endif /* ALTIVEC_USE_REFERENCE_C_CODE */
 169 }