mpegvideo_alpha.c

   1 /*
   2  * Alpha optimized DSP utils
   3  * Copyright (c) 2002 Falk Hueffner <falk@debian.org>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "libavutil/attributes.h"
  23 #include "libavcodec/mpegvideo.h"
  24 #include "asm.h"
  25
  26 static void dct_unquantize_h263_axp(int16_t *block, int n_coeffs,
  27                                     uint64_t qscale, uint64_t qadd)
  28 {
  29     uint64_t qmul = qscale << 1;
  30     uint64_t correction = WORD_VEC(qmul * 255 >> 8);
  31     int i;
  32
  33     qadd = WORD_VEC(qadd);
  34
  35     for(i = 0; i <= n_coeffs; block += 4, i += 4) {
  36         uint64_t levels, negmask, zeros, add, sub;
  37
  38         levels = ldq(block);
  39         if (levels == 0)
  40             continue;
  41
  42 #ifdef __alpha_max__
  43         /* I don't think the speed difference justifies runtime
  44            detection.  */
  45         negmask = maxsw4(levels, -1); /* negative -> ffff (-1) */
  46         negmask = minsw4(negmask, 0); /* positive -> 0000 (0) */
  47 #else
  48         negmask = cmpbge(WORD_VEC(0x7fff), levels);
  49         negmask &= (negmask >> 1) | (1 << 7);
  50         negmask = zap(-1, negmask);
  51 #endif
  52
  53         zeros = cmpbge(0, levels);
  54         zeros &= zeros >> 1;
  55         /* zeros |= zeros << 1 is not needed since qadd <= 255, so
  56            zapping the lower byte suffices.  */
  57
  58         levels *= qmul;
  59         levels -= correction & (negmask << 16);
  60
  61         add = qadd & ~negmask;
  62         sub = qadd &  negmask;
  63         /* Set qadd to 0 for levels == 0.  */
  64         add = zap(add, zeros);
  65         levels += add;
  66         levels -= sub;
  67
  68         stq(levels, block);
  69     }
  70 }
  71
  72 static void dct_unquantize_h263_intra_axp(MpegEncContext *s, int16_t *block,
  73                                     int n, int qscale)
  74 {
  75     int n_coeffs;
  76     uint64_t qadd;
  77     int16_t block0 = block[0];
  78
  79     if (!s->h263_aic) {
  80         if (n < 4)
  81             block0 *= s->y_dc_scale;
  82         else
  83             block0 *= s->c_dc_scale;
  84         qadd = (qscale - 1) | 1;
  85     } else {
  86         qadd = 0;
  87     }
  88
  89     if(s->ac_pred)
  90         n_coeffs = 63;
  91     else
  92         n_coeffs = s->inter_scantable.raster_end[s->block_last_index[n]];
  93
  94     dct_unquantize_h263_axp(block, n_coeffs, qscale, qadd);
  95
  96     block[0] = block0;
  97 }
  98
  99 static void dct_unquantize_h263_inter_axp(MpegEncContext *s, int16_t *block,
 100                                     int n, int qscale)
 101 {
 102     int n_coeffs = s->inter_scantable.raster_end[s->block_last_index[n]];
 103     dct_unquantize_h263_axp(block, n_coeffs, qscale, (qscale - 1) | 1);
 104 }
 105
 106 av_cold void ff_mpv_common_init_axp(MpegEncContext *s)
 107 {
 108     s->dct_unquantize_h263_intra = dct_unquantize_h263_intra_axp;
 109     s->dct_unquantize_h263_inter = dct_unquantize_h263_inter_axp;
 110 }