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  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. }
  111.