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/*

 * mad - MPEG audio decoder

 * Copyright (C) 2000-2001 Robert Leslie

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * $Id: synth.c,v 1.3 2001-11-06 17:01:28 simons Exp $

 */

# ifdef HAVE_CONFIG_H

#  include "config.h"

# endif

# include "global.h"

# include "fixed.h"

# include "frame.h"

# include "synth.h"

# include "../audio.h"

#ifndef EMBED

# include <stdio.h>

#endif

/*

 * NAME:        synth->mute()

 * DESCRIPTION: zero all polyphase filterbank values, resetting synthesis

 */

void mad_synth_mute(struct mad_synth *synth)

{

  unsigned int ch, s, v;

  for (ch = 0; ch < 2; ++ch) {

    for (s = 0; s < 16; ++s) {

      for (v = 0; v < 8; ++v) {

        synth->filter[ch][0][0][s][v] = synth->filter[ch][0][1][s][v] =

        synth->filter[ch][1][0][s][v] = synth->filter[ch][1][1][s][v] = 0;

      }

    }

  }

}

/*

 * NAME:        synth->init()

 * DESCRIPTION: initialize synth struct

 */

inline void mad_synth_init(struct mad_synth *synth)

{

  mad_synth_mute(synth);

  synth->phase = 0;

  synth->pcm.samplerate = 0;

  synth->pcm.channels   = 0;

  synth->pcm.length     = 0;

}

/*

 * An optional optimization called here the Subband Synthesis Optimization

 * (SSO) improves the performance of subband synthesis at the expense of

 * accuracy.

 *

 * The idea is to simplify 32x32->64-bit multiplication to 32x32->32 such

 * that extra scaling and rounding are not necessary. This often allows the

 * compiler to use faster 32-bit multiply-accumulate instructions instead of

 * explicit 64-bit multiply, shift, and add instructions.

 *

 * SSO works like this: a full 32x32->64-bit multiply of two mad_fixed_t

 * values requires the result to be right-shifted 28 bits to be properly

 * scaled to the same fixed-point format. Right shifts can be applied at any

 * time to either operand or to the result, so the optimization involves

 * careful placement of these shifts to minimize the loss of accuracy.

 *

 * First, a 14-bit shift is applied with rounding at compile-time to the D[]

 * table of coefficients for the subband synthesis window. This only loses 2

 * bits of accuracy because the lower 12 bits are always zero. A second

 * 12-bit shift occurs after the DCT calculation. This loses 12 bits of

 * accuracy. Finally, a third 2-bit shift occurs just before the sample is

 * saved in the PCM buffer. 14 + 12 + 2 == 28 bits.

 */

/* FPM_DEFAULT without OPT_SSO will actually lose accuracy and performance */

# if defined(FPM_DEFAULT) && !defined(OPT_SSO)

#  define OPT_SSO

# endif

/* second SSO shift, with rounding */

# if defined(OPT_SSO)

#  define SHIFT(x)  (((x) + (1L << 11)) >> 12)

# else

#  define SHIFT(x)  (x)

# endif

/* possible DCT speed optimization */

# if defined(OPT_SPEED) && defined(MAD_F_MLX)

#  define OPT_DCTO

#  define MUL(x, y)  \

    ({ mad_fixed64hi_t hi;  \

       mad_fixed64lo_t lo;  \

       MAD_F_MLX(hi, lo, (x), (y));  \

       hi << (32 - MAD_F_SCALEBITS - 3);  \

    })

# else

#  undef OPT_DCTO

#  define MUL(x, y)  mad_f_mul((x), (y))

# endif

/*

 * NAME:        dct32()

 * DESCRIPTION: perform fast in[32]->out[32] DCT

 */

static

void dct32(mad_fixed_t const in[32], unsigned int slot,

           mad_fixed_t lo[16][8], mad_fixed_t hi[16][8])

{

  mad_fixed_t t0,   t1,   t2,   t3,   t4,   t5,   t6,   t7;

  mad_fixed_t t8,   t9,   t10,  t11,  t12,  t13,  t14,  t15;

  mad_fixed_t t16,  t17,  t18,  t19,  t20,  t21,  t22,  t23;

  mad_fixed_t t24,  t25,  t26,  t27,  t28,  t29,  t30,  t31;

  mad_fixed_t t32,  t33,  t34,  t35,  t36,  t37,  t38,  t39;

  mad_fixed_t t40,  t41,  t42,  t43,  t44,  t45,  t46,  t47;

  mad_fixed_t t48,  t49,  t50,  t51,  t52,  t53,  t54,  t55;

  mad_fixed_t t56,  t57,  t58,  t59,  t60,  t61,  t62,  t63;

  mad_fixed_t t64,  t65,  t66,  t67,  t68,  t69,  t70,  t71;

  mad_fixed_t t72,  t73,  t74,  t75,  t76,  t77,  t78,  t79;

  mad_fixed_t t80,  t81,  t82,  t83,  t84,  t85,  t86,  t87;

  mad_fixed_t t88,  t89,  t90,  t91,  t92,  t93,  t94,  t95;

  mad_fixed_t t96,  t97,  t98,  t99,  t100, t101, t102, t103;

  mad_fixed_t t104, t105, t106, t107, t108, t109, t110, t111;

  mad_fixed_t t112, t113, t114, t115, t116, t117, t118, t119;

  mad_fixed_t t120, t121, t122, t123, t124, t125, t126, t127;

  mad_fixed_t t128, t129, t130, t131, t132, t133, t134, t135;

  mad_fixed_t t136, t137, t138, t139, t140, t141, t142, t143;

  mad_fixed_t t144, t145, t146, t147, t148, t149, t150, t151;

  mad_fixed_t t152, t153, t154, t155, t156, t157, t158, t159;

  mad_fixed_t t160, t161, t162, t163, t164, t165, t166, t167;

  mad_fixed_t t168, t169, t170, t171, t172, t173, t174, t175;

  mad_fixed_t t176;

  /* costab[i] = cos(PI / (2 * 32) * i) */

# if defined(OPT_DCTO)

  enum {

    costab1  = MAD_F(0x7fd8878e),

    costab2  = MAD_F(0x7f62368f),

    costab3  = MAD_F(0x7e9d55fc),

    costab4  = MAD_F(0x7d8a5f40),

    costab5  = MAD_F(0x7c29fbee),

    costab6  = MAD_F(0x7a7d055b),

    costab7  = MAD_F(0x78848414),

    costab8  = MAD_F(0x7641af3d),

    costab9  = MAD_F(0x73b5ebd1),

    costab10 = MAD_F(0x70e2cbc6),

    costab11 = MAD_F(0x6dca0d14),

    costab12 = MAD_F(0x6a6d98a4),

    costab13 = MAD_F(0x66cf8120),

    costab14 = MAD_F(0x62f201ac),

    costab15 = MAD_F(0x5ed77c8a),

    costab16 = MAD_F(0x5a82799a),

    costab17 = MAD_F(0x55f5a4d2),

    costab18 = MAD_F(0x5133cc94),

    costab19 = MAD_F(0x4c3fdff4),

    costab20 = MAD_F(0x471cece7),

    costab21 = MAD_F(0x41ce1e65),

    costab22 = MAD_F(0x3c56ba70),

    costab23 = MAD_F(0x36ba2014),

    costab24 = MAD_F(0x30fbc54d),

    costab25 = MAD_F(0x2b1f34eb),

    costab26 = MAD_F(0x25280c5e),

    costab27 = MAD_F(0x1f19f97b),

    costab28 = MAD_F(0x18f8b83c),

    costab29 = MAD_F(0x12c8106f),

    costab30 = MAD_F(0x0c8bd35e),

    costab31 = MAD_F(0x0647d97c)

  };

# else

  enum {

    costab1  = MAD_F(0x0ffb10f2),  /* 0.998795456 */

    costab2  = MAD_F(0x0fec46d2),  /* 0.995184727 */

    costab3  = MAD_F(0x0fd3aac0),  /* 0.989176510 */

    costab4  = MAD_F(0x0fb14be8),  /* 0.980785280 */

    costab5  = MAD_F(0x0f853f7e),  /* 0.970031253 */

    costab6  = MAD_F(0x0f4fa0ab),  /* 0.956940336 */

    costab7  = MAD_F(0x0f109082),  /* 0.941544065 */

    costab8  = MAD_F(0x0ec835e8),  /* 0.923879533 */

    costab9  = MAD_F(0x0e76bd7a),  /* 0.903989293 */

    costab10 = MAD_F(0x0e1c5979),  /* 0.881921264 */

    costab11 = MAD_F(0x0db941a3),  /* 0.857728610 */

    costab12 = MAD_F(0x0d4db315),  /* 0.831469612 */

    costab13 = MAD_F(0x0cd9f024),  /* 0.803207531 */

    costab14 = MAD_F(0x0c5e4036),  /* 0.773010453 */

    costab15 = MAD_F(0x0bdaef91),  /* 0.740951125 */

    costab16 = MAD_F(0x0b504f33),  /* 0.707106781 */

    costab17 = MAD_F(0x0abeb49a),  /* 0.671558955 */

    costab18 = MAD_F(0x0a267993),  /* 0.634393284 */

    costab19 = MAD_F(0x0987fbfe),  /* 0.595699304 */

    costab20 = MAD_F(0x08e39d9d),  /* 0.555570233 */

    costab21 = MAD_F(0x0839c3cd),  /* 0.514102744 */

    costab22 = MAD_F(0x078ad74e),  /* 0.471396737 */

    costab23 = MAD_F(0x06d74402),  /* 0.427555093 */

    costab24 = MAD_F(0x061f78aa),  /* 0.382683432 */

    costab25 = MAD_F(0x0563e69d),  /* 0.336889853 */

    costab26 = MAD_F(0x04a5018c),  /* 0.290284677 */

    costab27 = MAD_F(0x03e33f2f),  /* 0.242980180 */

    costab28 = MAD_F(0x031f1708),  /* 0.195090322 */

    costab29 = MAD_F(0x0259020e),  /* 0.146730474 */

    costab30 = MAD_F(0x01917a6c),  /* 0.098017140 */

    costab31 = MAD_F(0x00c8fb30)   /* 0.049067674 */

  };

# endif

  t0   = in[0]  + in[31];  t16  = MUL(in[0]  - in[31], costab1);

  t1   = in[15] + in[16];  t17  = MUL(in[15] - in[16], costab31);

  t41  = t16 + t17;

  t59  = MUL(t16 - t17, costab2);

  t33  = t0  + t1;

  t50  = MUL(t0  - t1,  costab2);

  t2   = in[7]  + in[24];  t18  = MUL(in[7]  - in[24], costab15);

  t3   = in[8]  + in[23];  t19  = MUL(in[8]  - in[23], costab17);

  t42  = t18 + t19;

  t60  = MUL(t18 - t19, costab30);

  t34  = t2  + t3;

  t51  = MUL(t2  - t3,  costab30);

  t4   = in[3]  + in[28];  t20  = MUL(in[3]  - in[28], costab7);

  t5   = in[12] + in[19];  t21  = MUL(in[12] - in[19], costab25);

  t43  = t20 + t21;

  t61  = MUL(t20 - t21, costab14);

  t35  = t4  + t5;

  t52  = MUL(t4  - t5,  costab14);

  t6   = in[4]  + in[27];  t22  = MUL(in[4]  - in[27], costab9);

  t7   = in[11] + in[20];  t23  = MUL(in[11] - in[20], costab23);

  t44  = t22 + t23;

  t62  = MUL(t22 - t23, costab18);

  t36  = t6  + t7;

  t53  = MUL(t6  - t7,  costab18);

  t8   = in[1]  + in[30];  t24  = MUL(in[1]  - in[30], costab3);

  t9   = in[14] + in[17];  t25  = MUL(in[14] - in[17], costab29);

  t45  = t24 + t25;

  t63  = MUL(t24 - t25, costab6);

  t37  = t8  + t9;

  t54  = MUL(t8  - t9,  costab6);

  t10  = in[6]  + in[25];  t26  = MUL(in[6]  - in[25], costab13);

  t11  = in[9]  + in[22];  t27  = MUL(in[9]  - in[22], costab19);

  t46  = t26 + t27;

  t64  = MUL(t26 - t27, costab26);

  t38  = t10 + t11;

  t55  = MUL(t10 - t11, costab26);

  t12  = in[2]  + in[29];  t28  = MUL(in[2]  - in[29], costab5);

  t13  = in[13] + in[18];  t29  = MUL(in[13] - in[18], costab27);

  t47  = t28 + t29;

  t65  = MUL(t28 - t29, costab10);

  t39  = t12 + t13;

  t56  = MUL(t12 - t13, costab10);

  t14  = in[5]  + in[26];  t30  = MUL(in[5]  - in[26], costab11);

  t15  = in[10] + in[21];  t31  = MUL(in[10] - in[21], costab21);

  t48  = t30 + t31;

  t66  = MUL(t30 - t31, costab22);

  t40  = t14 + t15;

  t57  = MUL(t14 - t15, costab22);

  t69  = t33 + t34;  t89  = MUL(t33 - t34, costab4);

  t70  = t35 + t36;  t90  = MUL(t35 - t36, costab28);

  t71  = t37 + t38;  t91  = MUL(t37 - t38, costab12);

  t72  = t39 + t40;  t92  = MUL(t39 - t40, costab20);

  t73  = t41 + t42;  t94  = MUL(t41 - t42, costab4);

  t74  = t43 + t44;  t95  = MUL(t43 - t44, costab28);

  t75  = t45 + t46;  t96  = MUL(t45 - t46, costab12);

  t76  = t47 + t48;  t97  = MUL(t47 - t48, costab20);

  t78  = t50 + t51;  t100 = MUL(t50 - t51, costab4);

  t79  = t52 + t53;  t101 = MUL(t52 - t53, costab28);

  t80  = t54 + t55;  t102 = MUL(t54 - t55, costab12);

  t81  = t56 + t57;  t103 = MUL(t56 - t57, costab20);

  t83  = t59 + t60;  t106 = MUL(t59 - t60, costab4);

  t84  = t61 + t62;  t107 = MUL(t61 - t62, costab28);

  t85  = t63 + t64;  t108 = MUL(t63 - t64, costab12);

  t86  = t65 + t66;  t109 = MUL(t65 - t66, costab20);

  t113 = t69  + t70;

  t114 = t71  + t72;

  /*  0 */ hi[15][slot] = SHIFT(t113 + t114);

  /* 16 */ lo[ 0][slot] = SHIFT(MUL(t113 - t114, costab16));

  t115 = t73  + t74;

  t116 = t75  + t76;

  t32  = t115 + t116;

  /*  1 */ hi[14][slot] = SHIFT(t32);

  t118 = t78  + t79;

  t119 = t80  + t81;

  t58  = t118 + t119;

  /*  2 */ hi[13][slot] = SHIFT(t58);

  t121 = t83  + t84;

  t122 = t85  + t86;

  t67  = t121 + t122;

  t49  = (t67 << 1) - t32;

  /*  3 */ hi[12][slot] = SHIFT(t49);

  t125 = t89  + t90;

  t126 = t91  + t92;

  t93  = t125 + t126;

  /*  4 */ hi[11][slot] = SHIFT(t93);

  t128 = t94  + t95;

  t129 = t96  + t97;

  t98  = t128 + t129;

  t68  = (t98 << 1) - t49;

  /*  5 */ hi[10][slot] = SHIFT(t68);

  t132 = t100 + t101;

  t133 = t102 + t103;

  t104 = t132 + t133;

  t82  = (t104 << 1) - t58;

  /*  6 */ hi[ 9][slot] = SHIFT(t82);

  t136 = t106 + t107;

  t137 = t108 + t109;

  t110 = t136 + t137;

  t87  = (t110 << 1) - t67;

  t77  = (t87 << 1) - t68;

  /*  7 */ hi[ 8][slot] = SHIFT(t77);

  t141 = MUL(t69 - t70, costab8);

  t142 = MUL(t71 - t72, costab24);

  t143 = t141 + t142;

  /*  8 */ hi[ 7][slot] = SHIFT(t143);

  /* 24 */ lo[ 8][slot] =

             SHIFT((MUL(t141 - t142, costab16) << 1) - t143);

  t144 = MUL(t73 - t74, costab8);

  t145 = MUL(t75 - t76, costab24);

  t146 = t144 + t145;

  t88  = (t146 << 1) - t77;

  /*  9 */ hi[ 6][slot] = SHIFT(t88);

  t148 = MUL(t78 - t79, costab8);

  t149 = MUL(t80 - t81, costab24);

  t150 = t148 + t149;

  t105 = (t150 << 1) - t82;

  /* 10 */ hi[ 5][slot] = SHIFT(t105);

  t152 = MUL(t83 - t84, costab8);

  t153 = MUL(t85 - t86, costab24);

  t154 = t152 + t153;

  t111 = (t154 << 1) - t87;

  t99  = (t111 << 1) - t88;

  /* 11 */ hi[ 4][slot] = SHIFT(t99);

  t157 = MUL(t89 - t90, costab8);

  t158 = MUL(t91 - t92, costab24);

  t159 = t157 + t158;

  t127 = (t159 << 1) - t93;

  /* 12 */ hi[ 3][slot] = SHIFT(t127);

  t160 = (MUL(t125 - t126, costab16) << 1) - t127;

  /* 20 */ lo[ 4][slot] = SHIFT(t160);

  /* 28 */ lo[12][slot] =

             SHIFT((((MUL(t157 - t158, costab16) << 1) - t159) << 1) - t160);

  t161 = MUL(t94 - t95, costab8);

  t162 = MUL(t96 - t97, costab24);

  t163 = t161 + t162;

  t130 = (t163 << 1) - t98;

  t112 = (t130 << 1) - t99;

  /* 13 */ hi[ 2][slot] = SHIFT(t112);

  t164 = (MUL(t128 - t129, costab16) << 1) - t130;

  t166 = MUL(t100 - t101, costab8);

  t167 = MUL(t102 - t103, costab24);

  t168 = t166 + t167;

  t134 = (t168 << 1) - t104;

  t120 = (t134 << 1) - t105;

  /* 14 */ hi[ 1][slot] = SHIFT(t120);

  t135 = (MUL(t118 - t119, costab16) << 1) - t120;

  /* 18 */ lo[ 2][slot] = SHIFT(t135);

  t169 = (MUL(t132 - t133, costab16) << 1) - t134;

  t151 = (t169 << 1) - t135;

  /* 22 */ lo[ 6][slot] = SHIFT(t151);

  t170 = (((MUL(t148 - t149, costab16) << 1) - t150) << 1) - t151;

  /* 26 */ lo[10][slot] = SHIFT(t170);

  /* 30 */ lo[14][slot] =

             SHIFT((((((MUL(t166 - t167, costab16) << 1) -

                       t168) << 1) - t169) << 1) - t170);

  t171 = MUL(t106 - t107, costab8);

  t172 = MUL(t108 - t109, costab24);

  t173 = t171 + t172;

  t138 = (t173 << 1) - t110;

  t123 = (t138 << 1) - t111;

  t139 = (MUL(t121 - t122, costab16) << 1) - t123;

  t117 = (t123 << 1) - t112;

  /* 15 */ hi[ 0][slot] = SHIFT(t117);

  t124 = (MUL(t115 - t116, costab16) << 1) - t117;

  /* 17 */ lo[ 1][slot] = SHIFT(t124);

  t131 = (t139 << 1) - t124;

  /* 19 */ lo[ 3][slot] = SHIFT(t131);

  t140 = (t164 << 1) - t131;

  /* 21 */ lo[ 5][slot] = SHIFT(t140);

  t174 = (MUL(t136 - t137, costab16) << 1) - t138;

  t155 = (t174 << 1) - t139;

  t147 = (t155 << 1) - t140;

  /* 23 */ lo[ 7][slot] = SHIFT(t147);

  t156 = (((MUL(t144 - t145, costab16) << 1) - t146) << 1) - t147;

  /* 25 */ lo[ 9][slot] = SHIFT(t156);

  t175 = (((MUL(t152 - t153, costab16) << 1) - t154) << 1) - t155;

  t165 = (t175 << 1) - t156;

  /* 27 */ lo[11][slot] = SHIFT(t165);

  t176 = (((((MUL(t161 - t162, costab16) << 1) -

             t163) << 1) - t164) << 1) - t165;

  /* 29 */ lo[13][slot] = SHIFT(t176);

  /* 31 */ lo[15][slot] =

             SHIFT((((((((MUL(t171 - t172, costab16) << 1) -

                         t173) << 1) - t174) << 1) - t175) << 1) - t176);

  /*

   * Totals:

   *  80 multiplies

   *  80 additions

   * 119 subtractions

   *  49 shifts (not counting SSO)

   */

}

# undef MUL

# undef SHIFT

/* third SSO shift and/or D[] optimization preshift */

# if defined(OPT_SSO)

#  if MAD_F_FRACBITS != 28

#   error "MAD_F_FRACBITS must be 28 to use OPT_SSO"

#  endif

#  define ML0(hi, lo, x, y)     ((lo)  = (x) * (y))

#  define MLA(hi, lo, x, y)     ((lo) += (x) * (y))

#  define MLZ(hi, lo)           ((void) (hi), (mad_fixed_t) (lo))

#  define SHIFT(x)              ((x) >> 2)

#  define PRESHIFT(x)           ((MAD_F(x) + (1L << 13)) >> 14)

# else

#  define ML0(hi, lo, x, y)     MAD_F_ML0((hi), (lo), (x), (y))

#  define MLA(hi, lo, x, y)     MAD_F_MLA((hi), (lo), (x), (y))

#  define MLZ(hi, lo)           MAD_F_MLZ((hi), (lo))

#  define SHIFT(x)              (x)

#  if defined(MAD_F_SCALEBITS)

#   undef  MAD_F_SCALEBITS

#   define MAD_F_SCALEBITS      (MAD_F_FRACBITS - 12)

#   define PRESHIFT(x)          (MAD_F(x) >> 12)

#  else

#   define PRESHIFT(x)          MAD_F(x)

#  endif

# endif

static

mad_fixed_t const D[17][32] = {

# include "D.dat"

};

/* 3. called to process output */

int speed = 0, nchan = 0;

# ifndef EMBED

int output_s(unsigned char const *ptr, unsigned int len);

# endif

static inline void

output(struct mad_pcm *pcm)

{

  unsigned int nchannels;

  union audio_control control;

  mad_fixed_t *ch1, *ch2;

  nchannels = pcm->channels;

  if (nchannels != nchan || speed != pcm->samplerate)

    {

# ifndef EMBED

      control.command = AUDIO_COMMAND_CONFIG;

      control.config.channels = nchannels;

      control.config.speed    = pcm->samplerate;

      if (audio_oss(&control) == -1)

        return;

# endif 

      nchan = nchannels;

      speed = pcm->samplerate;

    }

  ch1 = &pcm->samples[0][0];

  ch2 = &pcm->samples[1][0];

  if (nchan == 1)

    ch2 = ch1;