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ffmpeg / libavcodec / dct32.c @ 2912e87a

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/*
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 * Template for the Discrete Cosine Transform for 32 samples
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 * Copyright (c) 2001, 2002 Fabrice Bellard
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#ifdef DCT32_FLOAT
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#   define FIXHR(x)       ((float)(x))
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#   define MULH3(x, y, s) ((s)*(y)*(x))
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#   define INTFLOAT float
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#endif
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/* tab[i][j] = 1.0 / (2.0 * cos(pi*(2*k+1) / 2^(6 - j))) */
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/* cos(i*pi/64) */
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#define COS0_0  FIXHR(0.50060299823519630134/2)
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#define COS0_1  FIXHR(0.50547095989754365998/2)
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#define COS0_2  FIXHR(0.51544730992262454697/2)
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#define COS0_3  FIXHR(0.53104259108978417447/2)
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#define COS0_4  FIXHR(0.55310389603444452782/2)
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#define COS0_5  FIXHR(0.58293496820613387367/2)
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#define COS0_6  FIXHR(0.62250412303566481615/2)
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#define COS0_7  FIXHR(0.67480834145500574602/2)
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#define COS0_8  FIXHR(0.74453627100229844977/2)
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#define COS0_9  FIXHR(0.83934964541552703873/2)
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#define COS0_10 FIXHR(0.97256823786196069369/2)
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#define COS0_11 FIXHR(1.16943993343288495515/4)
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#define COS0_12 FIXHR(1.48416461631416627724/4)
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#define COS0_13 FIXHR(2.05778100995341155085/8)
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#define COS0_14 FIXHR(3.40760841846871878570/8)
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#define COS0_15 FIXHR(10.19000812354805681150/32)
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#define COS1_0 FIXHR(0.50241928618815570551/2)
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#define COS1_1 FIXHR(0.52249861493968888062/2)
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#define COS1_2 FIXHR(0.56694403481635770368/2)
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#define COS1_3 FIXHR(0.64682178335999012954/2)
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#define COS1_4 FIXHR(0.78815462345125022473/2)
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#define COS1_5 FIXHR(1.06067768599034747134/4)
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#define COS1_6 FIXHR(1.72244709823833392782/4)
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#define COS1_7 FIXHR(5.10114861868916385802/16)
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#define COS2_0 FIXHR(0.50979557910415916894/2)
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#define COS2_1 FIXHR(0.60134488693504528054/2)
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#define COS2_2 FIXHR(0.89997622313641570463/2)
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#define COS2_3 FIXHR(2.56291544774150617881/8)
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#define COS3_0 FIXHR(0.54119610014619698439/2)
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#define COS3_1 FIXHR(1.30656296487637652785/4)
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#define COS4_0 FIXHR(0.70710678118654752439/2)
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/* butterfly operator */
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#define BF(a, b, c, s)\
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{\
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    tmp0 = val##a + val##b;\
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    tmp1 = val##a - val##b;\
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    val##a = tmp0;\
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    val##b = MULH3(tmp1, c, 1<<(s));\
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}
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#define BF0(a, b, c, s)\
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{\
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    tmp0 = tab[a] + tab[b];\
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    tmp1 = tab[a] - tab[b];\
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    val##a = tmp0;\
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    val##b = MULH3(tmp1, c, 1<<(s));\
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}
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#define BF1(a, b, c, d)\
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{\
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    BF(a, b, COS4_0, 1);\
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    BF(c, d,-COS4_0, 1);\
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    val##c += val##d;\
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}
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#define BF2(a, b, c, d)\
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{\
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    BF(a, b, COS4_0, 1);\
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    BF(c, d,-COS4_0, 1);\
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    val##c += val##d;\
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    val##a += val##c;\
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    val##c += val##b;\
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    val##b += val##d;\
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}
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#define ADD(a, b) val##a += val##b
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/* DCT32 without 1/sqrt(2) coef zero scaling. */
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static void dct32(INTFLOAT *out, const INTFLOAT *tab)
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{
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    INTFLOAT tmp0, tmp1;
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    INTFLOAT val0 , val1 , val2 , val3 , val4 , val5 , val6 , val7 ,
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             val8 , val9 , val10, val11, val12, val13, val14, val15,
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             val16, val17, val18, val19, val20, val21, val22, val23,
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             val24, val25, val26, val27, val28, val29, val30, val31;
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    /* pass 1 */
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    BF0( 0, 31, COS0_0 , 1);
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    BF0(15, 16, COS0_15, 5);
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    /* pass 2 */
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    BF( 0, 15, COS1_0 , 1);
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    BF(16, 31,-COS1_0 , 1);
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    /* pass 1 */
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    BF0( 7, 24, COS0_7 , 1);
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    BF0( 8, 23, COS0_8 , 1);
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    /* pass 2 */
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    BF( 7,  8, COS1_7 , 4);
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    BF(23, 24,-COS1_7 , 4);
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    /* pass 3 */
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    BF( 0,  7, COS2_0 , 1);
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    BF( 8, 15,-COS2_0 , 1);
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    BF(16, 23, COS2_0 , 1);
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    BF(24, 31,-COS2_0 , 1);
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    /* pass 1 */
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    BF0( 3, 28, COS0_3 , 1);
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    BF0(12, 19, COS0_12, 2);
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    /* pass 2 */
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    BF( 3, 12, COS1_3 , 1);
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    BF(19, 28,-COS1_3 , 1);
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    /* pass 1 */
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    BF0( 4, 27, COS0_4 , 1);
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    BF0(11, 20, COS0_11, 2);
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    /* pass 2 */
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    BF( 4, 11, COS1_4 , 1);
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    BF(20, 27,-COS1_4 , 1);
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    /* pass 3 */
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    BF( 3,  4, COS2_3 , 3);
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    BF(11, 12,-COS2_3 , 3);
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    BF(19, 20, COS2_3 , 3);
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    BF(27, 28,-COS2_3 , 3);
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    /* pass 4 */
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    BF( 0,  3, COS3_0 , 1);
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    BF( 4,  7,-COS3_0 , 1);
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    BF( 8, 11, COS3_0 , 1);
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    BF(12, 15,-COS3_0 , 1);
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    BF(16, 19, COS3_0 , 1);
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    BF(20, 23,-COS3_0 , 1);
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    BF(24, 27, COS3_0 , 1);
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    BF(28, 31,-COS3_0 , 1);
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    /* pass 1 */
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    BF0( 1, 30, COS0_1 , 1);
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    BF0(14, 17, COS0_14, 3);
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    /* pass 2 */
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    BF( 1, 14, COS1_1 , 1);
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    BF(17, 30,-COS1_1 , 1);
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    /* pass 1 */
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    BF0( 6, 25, COS0_6 , 1);
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    BF0( 9, 22, COS0_9 , 1);
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    /* pass 2 */
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    BF( 6,  9, COS1_6 , 2);
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    BF(22, 25,-COS1_6 , 2);
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    /* pass 3 */
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    BF( 1,  6, COS2_1 , 1);
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    BF( 9, 14,-COS2_1 , 1);
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    BF(17, 22, COS2_1 , 1);
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    BF(25, 30,-COS2_1 , 1);
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    /* pass 1 */
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    BF0( 2, 29, COS0_2 , 1);
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    BF0(13, 18, COS0_13, 3);
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    /* pass 2 */
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    BF( 2, 13, COS1_2 , 1);
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    BF(18, 29,-COS1_2 , 1);
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    /* pass 1 */
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    BF0( 5, 26, COS0_5 , 1);
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    BF0(10, 21, COS0_10, 1);
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    /* pass 2 */
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    BF( 5, 10, COS1_5 , 2);
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    BF(21, 26,-COS1_5 , 2);
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    /* pass 3 */
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    BF( 2,  5, COS2_2 , 1);
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    BF(10, 13,-COS2_2 , 1);
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    BF(18, 21, COS2_2 , 1);
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    BF(26, 29,-COS2_2 , 1);
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    /* pass 4 */
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    BF( 1,  2, COS3_1 , 2);
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    BF( 5,  6,-COS3_1 , 2);
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    BF( 9, 10, COS3_1 , 2);
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    BF(13, 14,-COS3_1 , 2);
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    BF(17, 18, COS3_1 , 2);
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    BF(21, 22,-COS3_1 , 2);
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    BF(25, 26, COS3_1 , 2);
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    BF(29, 30,-COS3_1 , 2);
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    /* pass 5 */
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    BF1( 0,  1,  2,  3);
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    BF2( 4,  5,  6,  7);
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    BF1( 8,  9, 10, 11);
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    BF2(12, 13, 14, 15);
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    BF1(16, 17, 18, 19);
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    BF2(20, 21, 22, 23);
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    BF1(24, 25, 26, 27);
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    BF2(28, 29, 30, 31);
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    /* pass 6 */
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    ADD( 8, 12);
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    ADD(12, 10);
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    ADD(10, 14);
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    ADD(14,  9);
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    ADD( 9, 13);
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    ADD(13, 11);
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    ADD(11, 15);
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    out[ 0] = val0;
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    out[16] = val1;
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    out[ 8] = val2;
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    out[24] = val3;
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    out[ 4] = val4;
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    out[20] = val5;
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    out[12] = val6;
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    out[28] = val7;
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    out[ 2] = val8;
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    out[18] = val9;
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    out[10] = val10;
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    out[26] = val11;
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    out[ 6] = val12;
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    out[22] = val13;
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    out[14] = val14;
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    out[30] = val15;
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    ADD(24, 28);
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    ADD(28, 26);
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    ADD(26, 30);
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    ADD(30, 25);
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    ADD(25, 29);
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    ADD(29, 27);
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    ADD(27, 31);
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    out[ 1] = val16 + val24;
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    out[17] = val17 + val25;
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    out[ 9] = val18 + val26;
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    out[25] = val19 + val27;
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    out[ 5] = val20 + val28;
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    out[21] = val21 + val29;
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    out[13] = val22 + val30;
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    out[29] = val23 + val31;
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    out[ 3] = val24 + val20;
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    out[19] = val25 + val21;
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    out[11] = val26 + val22;
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    out[27] = val27 + val23;
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    out[ 7] = val28 + val18;
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    out[23] = val29 + val19;
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    out[15] = val30 + val17;
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    out[31] = val31;
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}