fdct_mmx.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

/*
 * MMX optimized forward DCT
 * The gcc porting is Copyright (c) 2001 Fabrice Bellard.
 * cleanup/optimizations are Copyright (c) 2002-2004 Michael Niedermayer <[e-mail]>
 * SSE2 optimization is Copyright (c) 2004 Denes Balatoni.
 *
 * from  fdctam32.c - AP922 MMX(3D-Now) forward-DCT
 *
 *  Intel Application Note AP-922 - fast, precise implementation of DCT
 *        http://developer.intel.com/vtune/cbts/appnotes.htm
 *
 * Also of inspiration:
 * a page about fdct at http://www.geocities.com/ssavekar/dct.htm
 * Skal's fdct at http://skal.planet-d.net/coding/dct.html
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include "common.h"
#include "dsputil.h"
#include "mmx.h"

#define ATTR_ALIGN(align) __attribute__ ((__aligned__ (align)))

//////////////////////////////////////////////////////////////////////
//
// constants for the forward DCT
// -----------------------------
//
// Be sure to check that your compiler is aligning all constants to QWORD
// (8-byte) memory boundaries!  Otherwise the unaligned memory access will
// severely stall MMX execution.
//
//////////////////////////////////////////////////////////////////////

#define BITS_FRW_ACC   3 //; 2 or 3 for accuracy
#define SHIFT_FRW_COL  BITS_FRW_ACC
#define SHIFT_FRW_ROW  (BITS_FRW_ACC + 17 - 3)
#define RND_FRW_ROW    (1 << (SHIFT_FRW_ROW-1))
//#define RND_FRW_COL    (1 << (SHIFT_FRW_COL-1))

#define X8(x) x,x,x,x,x,x,x,x

//concatenated table, for forward DCT transformation
static const int16_t fdct_tg_all_16[24] ATTR_ALIGN(16) = {
    X8(13036),  // tg * (2<<16) + 0.5
    X8(27146),  // tg * (2<<16) + 0.5
    X8(-21746)  // tg * (2<<16) + 0.5
};

static const int16_t ocos_4_16[8] ATTR_ALIGN(16) = {
    X8(23170)   //cos * (2<<15) + 0.5
};

static const int16_t fdct_one_corr[8] ATTR_ALIGN(16) = { X8(1) };

static const int32_t fdct_r_row[2] ATTR_ALIGN(8) = {RND_FRW_ROW, RND_FRW_ROW };

static struct
{
 const int32_t fdct_r_row_sse2[4] ATTR_ALIGN(16);
} fdct_r_row_sse2 ATTR_ALIGN(16)=
{{
 RND_FRW_ROW, RND_FRW_ROW, RND_FRW_ROW, RND_FRW_ROW
}};
//static const long fdct_r_row_sse2[4] ATTR_ALIGN(16) = {RND_FRW_ROW, RND_FRW_ROW, RND_FRW_ROW, RND_FRW_ROW};

static const int16_t tab_frw_01234567[] ATTR_ALIGN(8) = {  // forward_dct coeff table
  16384,   16384,   22725,   19266,
  16384,   16384,   12873,    4520,
  21407,    8867,   19266,   -4520,
  -8867,  -21407,  -22725,  -12873,
  16384,  -16384,   12873,  -22725,
 -16384,   16384,    4520,   19266,
   8867,  -21407,    4520,  -12873,
  21407,   -8867,   19266,  -22725,

  22725,   22725,   31521,   26722,
  22725,   22725,   17855,    6270,
  29692,   12299,   26722,   -6270,
 -12299,  -29692,  -31521,  -17855,
  22725,  -22725,   17855,  -31521,
 -22725,   22725,    6270,   26722,
  12299,  -29692,    6270,  -17855,
  29692,  -12299,   26722,  -31521,

  21407,   21407,   29692,   25172,
  21407,   21407,   16819,    5906,
  27969,   11585,   25172,   -5906,
 -11585,  -27969,  -29692,  -16819,
  21407,  -21407,   16819,  -29692,
 -21407,   21407,    5906,   25172,
  11585,  -27969,    5906,  -16819,
  27969,  -11585,   25172,  -29692,

  19266,   19266,   26722,   22654,
  19266,   19266,   15137,    5315,
  25172,   10426,   22654,   -5315,
 -10426,  -25172,  -26722,  -15137,
  19266,  -19266,   15137,  -26722,
 -19266,   19266,    5315,   22654,
  10426,  -25172,    5315,  -15137,
  25172,  -10426,   22654,  -26722,

  16384,   16384,   22725,   19266,
  16384,   16384,   12873,    4520,
  21407,    8867,   19266,   -4520,
  -8867,  -21407,  -22725,  -12873,
  16384,  -16384,   12873,  -22725,
 -16384,   16384,    4520,   19266,
   8867,  -21407,    4520,  -12873,
  21407,   -8867,   19266,  -22725,

  19266,   19266,   26722,   22654,
  19266,   19266,   15137,    5315,
  25172,   10426,   22654,   -5315,
 -10426,  -25172,  -26722,  -15137,
  19266,  -19266,   15137,  -26722,
 -19266,   19266,    5315,   22654,
  10426,  -25172,    5315,  -15137,
  25172,  -10426,   22654,  -26722,

  21407,   21407,   29692,   25172,
  21407,   21407,   16819,    5906,
  27969,   11585,   25172,   -5906,
 -11585,  -27969,  -29692,  -16819,
  21407,  -21407,   16819,  -29692,
 -21407,   21407,    5906,   25172,
  11585,  -27969,    5906,  -16819,
  27969,  -11585,   25172,  -29692,

  22725,   22725,   31521,   26722,
  22725,   22725,   17855,    6270,
  29692,   12299,   26722,   -6270,
 -12299,  -29692,  -31521,  -17855,
  22725,  -22725,   17855,  -31521,
 -22725,   22725,    6270,   26722,
  12299,  -29692,    6270,  -17855,
  29692,  -12299,   26722,  -31521,
};

static struct
{
 const int16_t tab_frw_01234567_sse2[256] ATTR_ALIGN(16);
} tab_frw_01234567_sse2 ATTR_ALIGN(16) =
{{
//static const int16_t tab_frw_01234567_sse2[] ATTR_ALIGN(16) = {  // forward_dct coeff table
#define TABLE_SSE2 C4,  C4,  C1,  C3, -C6, -C2, -C1, -C5, \
                   C4,  C4,  C5,  C7,  C2,  C6,  C3, -C7, \
                  -C4,  C4,  C7,  C3,  C6, -C2,  C7, -C5, \
                   C4, -C4,  C5, -C1,  C2, -C6,  C3, -C1,
// c1..c7 * cos(pi/4) * 2^15
#define C1 22725
#define C2 21407
#define C3 19266
#define C4 16384
#define C5 12873
#define C6 8867
#define C7 4520
TABLE_SSE2

#undef C1
#undef C2
#undef C3
#undef C4
#undef C5
#undef C6
#undef C7
#define C1 31521
#define C2 29692
#define C3 26722
#define C4 22725
#define C5 17855
#define C6 12299
#define C7 6270
TABLE_SSE2

#undef C1
#undef C2
#undef C3
#undef C4
#undef C5
#undef C6
#undef C7
#define C1 29692
#define C2 27969
#define C3 25172
#define C4 21407
#define C5 16819
#define C6 11585
#define C7 5906
TABLE_SSE2

#undef C1
#undef C2
#undef C3
#undef C4
#undef C5
#undef C6
#undef C7
#define C1 26722
#define C2 25172
#define C3 22654
#define C4 19266
#define C5 15137
#define C6 10426
#define C7 5315
TABLE_SSE2

#undef C1
#undef C2
#undef C3
#undef C4
#undef C5
#undef C6
#undef C7
#define C1 22725
#define C2 21407
#define C3 19266
#define C4 16384
#define C5 12873
#define C6 8867
#define C7 4520
TABLE_SSE2

#undef C1
#undef C2
#undef C3
#undef C4
#undef C5
#undef C6
#undef C7
#define C1 26722
#define C2 25172
#define C3 22654
#define C4 19266
#define C5 15137
#define C6 10426
#define C7 5315
TABLE_SSE2

#undef C1
#undef C2
#undef C3
#undef C4
#undef C5
#undef C6
#undef C7
#define C1 29692
#define C2 27969
#define C3 25172
#define C4 21407
#define C5 16819
#define C6 11585
#define C7 5906
TABLE_SSE2

#undef C1
#undef C2
#undef C3
#undef C4
#undef C5
#undef C6
#undef C7
#define C1 31521
#define C2 29692
#define C3 26722
#define C4 22725
#define C5 17855
#define C6 12299
#define C7 6270
TABLE_SSE2