mpegvideodsp.c

   1 /*
   2  * GMC (Global Motion Compensation), AltiVec-enabled
   3  *
   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 "libavutil/mem.h"
  24 #include "libavutil/ppc/types_altivec.h"
  25 #include "libavutil/ppc/util_altivec.h"
  26 #include "libavcodec/mpegvideodsp.h"
  27
  28 #if HAVE_ALTIVEC
  29 /* AltiVec-enhanced gmc1. ATM this code assumes stride is a multiple of 8
  30  * to preserve proper dst alignment. */
  31 static void gmc1_altivec(uint8_t *dst /* align 8 */, uint8_t *src /* align1 */,
  32                          int stride, int h, int x16, int y16, int rounder)
  33 {
  34     int i;
  35     const DECLARE_ALIGNED(16, unsigned short, rounder_a) = rounder;
  36     const DECLARE_ALIGNED(16, unsigned short, ABCD)[8] = {
  37         (16 - x16) * (16 - y16), /* A */
  38              (x16) * (16 - y16), /* B */
  39         (16 - x16) * (y16),      /* C */
  40              (x16) * (y16),      /* D */
  41         0, 0, 0, 0               /* padding */
  42     };
  43     register const vector unsigned char vczero =
  44         (const vector unsigned char) vec_splat_u8(0);
  45     register const vector unsigned short vcsr8 =
  46         (const vector unsigned short) vec_splat_u16(8);
  47     register vector unsigned char dstv, dstv2, srcvB, srcvC, srcvD;
  48     register vector unsigned short tempB, tempC, tempD;
  49     unsigned long dst_odd        = (unsigned long) dst & 0x0000000F;
  50     unsigned long src_really_odd = (unsigned long) src & 0x0000000F;
  51     register vector unsigned short tempA =
  52         vec_ld(0, (const unsigned short *) ABCD);
  53     register vector unsigned short Av = vec_splat(tempA, 0);
  54     register vector unsigned short Bv = vec_splat(tempA, 1);
  55     register vector unsigned short Cv = vec_splat(tempA, 2);
  56     register vector unsigned short Dv = vec_splat(tempA, 3);
  57     register vector unsigned short rounderV =
  58         vec_splat((vec_u16) vec_lde(0, &rounder_a), 0);
  59
  60     /* we'll be able to pick-up our 9 char elements at src from those
  61      * 32 bytes we load the first batch here, as inside the loop we can
  62      * reuse 'src + stride' from one iteration as the 'src' of the next. */
  63     register vector unsigned char src_0 = vec_ld(0, src);
  64     register vector unsigned char src_1 = vec_ld(16, src);
  65     register vector unsigned char srcvA = vec_perm(src_0, src_1,
  66                                                    vec_lvsl(0, src));
  67
  68     if (src_really_odd != 0x0000000F)
  69         /* If (src & 0xF) == 0xF, then (src + 1) is properly aligned
  70          * on the second vector. */
  71         srcvB = vec_perm(src_0, src_1, vec_lvsl(1, src));
  72     else
  73         srcvB = src_1;
  74     srcvA = vec_mergeh(vczero, srcvA);
  75     srcvB = vec_mergeh(vczero, srcvB);
  76
  77     for (i = 0; i < h; i++) {
  78         dst_odd        =   (unsigned long) dst            & 0x0000000F;
  79         src_really_odd = (((unsigned long) src) + stride) & 0x0000000F;
  80
  81         dstv = vec_ld(0, dst);
  82
  83         /* We'll be able to pick-up our 9 char elements at src + stride from
  84          * those 32 bytes then reuse the resulting 2 vectors srvcC and srcvD
  85          * as the next srcvA and srcvB. */
  86         src_0 = vec_ld(stride +  0, src);
  87         src_1 = vec_ld(stride + 16, src);
  88         srcvC = vec_perm(src_0, src_1, vec_lvsl(stride + 0, src));
  89
  90         if (src_really_odd != 0x0000000F)
  91             /* If (src & 0xF) == 0xF, then (src + 1) is properly aligned
  92              * on the second vector. */
  93             srcvD = vec_perm(src_0, src_1, vec_lvsl(stride + 1, src));
  94         else
  95             srcvD = src_1;
  96
  97         srcvC = vec_mergeh(vczero, srcvC);
  98         srcvD = vec_mergeh(vczero, srcvD);
  99
 100         /* OK, now we (finally) do the math :-)
 101          * Those four instructions replace 32 int muls & 32 int adds.
 102          * Isn't AltiVec nice? */
 103         tempA = vec_mladd((vector unsigned short) srcvA, Av, rounderV);
 104         tempB = vec_mladd((vector unsigned short) srcvB, Bv, tempA);
 105         tempC = vec_mladd((vector unsigned short) srcvC, Cv, tempB);
 106         tempD = vec_mladd((vector unsigned short) srcvD, Dv, tempC);
 107
 108         srcvA = srcvC;
 109         srcvB = srcvD;
 110
 111         tempD = vec_sr(tempD, vcsr8);
 112
 113         dstv2 = vec_pack(tempD, (vector unsigned short) vczero);
 114
 115         if (dst_odd)
 116             dstv2 = vec_perm(dstv, dstv2, vcprm(0, 1, s0, s1));
 117         else
 118             dstv2 = vec_perm(dstv, dstv2, vcprm(s0, s1, 2, 3));
 119
 120         vec_st(dstv2, 0, dst);
 121
 122         dst += stride;
 123         src += stride;
 124     }
 125 }
 126 #endif /* HAVE_ALTIVEC */
 127
 128 av_cold void ff_mpegvideodsp_init_ppc(MpegVideoDSPContext *c)
 129 {
 130 #if HAVE_ALTIVEC
 131     c->gmc1 = gmc1_altivec;
 132 #endif /* HAVE_ALTIVEC */
 133 }