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[/] [mpeg2fpga/] [trunk/] [tools/] [mpeg2dec/] [idctref.c] - Blame information for rev 2

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1 2 kdv
#ifdef HAVE_MMX
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#include <string.h>
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void Initialize_Reference_IDCT() { /* nothing */ }
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/* perform intel mmx IDCT matrix multiply for 8x8 coefficient block */
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void Reference_IDCT(block, i)
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short *block;
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int i;  /* is intra */
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{
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   if (0)
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        block[0] += 8;   /* add 0.5 to [0][0] for I-frames */
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   IDCT_mmx(block);
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}
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#else
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/* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */
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/*
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 * Disclaimer of Warranty
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 *
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 * These software programs are available to the user without any license fee or
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 * royalty on an "as is" basis.  The MPEG Software Simulation Group disclaims
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 * any and all warranties, whether express, implied, or statuary, including any
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 * implied warranties or merchantability or of fitness for a particular
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 * purpose.  In no event shall the copyright-holder be liable for any
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 * incidental, punitive, or consequential damages of any kind whatsoever
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 * arising from the use of these programs.
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 *
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 * This disclaimer of warranty extends to the user of these programs and user's
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 * customers, employees, agents, transferees, successors, and assigns.
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 *
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 * The MPEG Software Simulation Group does not represent or warrant that the
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 * programs furnished hereunder are free of infringement of any third-party
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 * patents.
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 *
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 * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,
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 * are subject to royalty fees to patent holders.  Many of these patents are
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 * general enough such that they are unavoidable regardless of implementation
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 * design.
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 *
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 */
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/*  Perform IEEE 1180 reference (64-bit floating point, separable 8x1
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 *  direct matrix multiply) Inverse Discrete Cosine Transform
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*/
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/* Here we use math.h to generate constants.  Compiler results may
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   vary a little */
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#include <math.h>
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#include "config.h"
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#ifndef PI
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# ifdef M_PI
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#  define PI M_PI
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# else
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#  define PI 3.14159265358979323846
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# endif
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#endif
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/* global declarations */
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void Initialize_Fast_IDCTref _ANSI_ARGS_((void));
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void Reference_IDCT _ANSI_ARGS_((short *block));
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/* private data */
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/* cosine transform matrix for 8x1 IDCT */
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static double c[8][8];
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/* initialize DCT coefficient matrix */
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void Initialize_Reference_IDCT()
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{
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  int freq, time;
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  double scale;
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  for (freq=0; freq < 8; freq++)
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  {
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    scale = (freq == 0) ? sqrt(0.125) : 0.5;
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    for (time=0; time<8; time++)
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      c[freq][time] = scale*cos((PI/8.0)*freq*(time + 0.5));
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  }
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}
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/* perform IDCT matrix multiply for 8x8 coefficient block */
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void Reference_IDCT(block)
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short *block;
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{
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  int i, j, k, v;
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  double partial_product;
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  double tmp[64];
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  for (i=0; i<8; i++)
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    for (j=0; j<8; j++)
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    {
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      partial_product = 0.0;
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      for (k=0; k<8; k++)
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        partial_product+= c[k][j]*block[8*i+k];
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      tmp[8*i+j] = partial_product;
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    }
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  /* Transpose operation is integrated into address mapping by switching
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     loop order of i and j */
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  for (j=0; j<8; j++)
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    for (i=0; i<8; i++)
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    {
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      partial_product = 0.0;
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      for (k=0; k<8; k++)
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        partial_product+= c[k][i]*tmp[8*k+j];
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      v = (int) floor(partial_product+0.5);
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      block[8*i+j] = (v<-256) ? -256 : ((v>255) ? 255 : v);
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    }
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}
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#endif

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