Diff: synth.cpp

Revision:

0:7627c79db971

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/synth.cpp	Fri Nov 26 12:18:30 2010 +0000
@@ -0,0 +1,855 @@
+/*
+ * libmad - MPEG audio decoder library
+ * Copyright (C) 2000-2004 Underbit Technologies, Inc.
+ *
+ * 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 1.1 2010/11/23 20:12:57 andy Exp $
+ */
+
+#  include "config.h"
+
+# include "global.h"
+
+# include "fixed.h"
+# include "frame.h"
+# include "synth.h"
+
+/*
+ * NAME:	synth->init()
+ * DESCRIPTION:	initialize synth struct
+ */
+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;
+}
+
+/*
+ * 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;
+      }
+    }
+  }
+}
+
+/*
+ * 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)
+#  define costab1	MAD_F(0x7fd8878e)
+#  define costab2	MAD_F(0x7f62368f)
+#  define costab3	MAD_F(0x7e9d55fc)
+#  define costab4	MAD_F(0x7d8a5f40)
+#  define costab5	MAD_F(0x7c29fbee)
+#  define costab6	MAD_F(0x7a7d055b)
+#  define costab7	MAD_F(0x78848414)
+#  define costab8	MAD_F(0x7641af3d)
+#  define costab9	MAD_F(0x73b5ebd1)
+#  define costab10	MAD_F(0x70e2cbc6)
+#  define costab11	MAD_F(0x6dca0d14)
+#  define costab12	MAD_F(0x6a6d98a4)
+#  define costab13	MAD_F(0x66cf8120)
+#  define costab14	MAD_F(0x62f201ac)
+#  define costab15	MAD_F(0x5ed77c8a)
+#  define costab16	MAD_F(0x5a82799a)
+#  define costab17	MAD_F(0x55f5a4d2)
+#  define costab18	MAD_F(0x5133cc94)
+#  define costab19	MAD_F(0x4c3fdff4)
+#  define costab20	MAD_F(0x471cece7)
+#  define costab21	MAD_F(0x41ce1e65)
+#  define costab22	MAD_F(0x3c56ba70)
+#  define costab23	MAD_F(0x36ba2014)
+#  define costab24	MAD_F(0x30fbc54d)
+#  define costab25	MAD_F(0x2b1f34eb)
+#  define costab26	MAD_F(0x25280c5e)
+#  define costab27	MAD_F(0x1f19f97b)
+#  define costab28	MAD_F(0x18f8b83c)
+#  define costab29	MAD_F(0x12c8106f)
+#  define costab30	MAD_F(0x0c8bd35e)
+#  define costab31	MAD_F(0x0647d97c)
+# else
+#  define costab1	MAD_F(0x0ffb10f2)  /* 0.998795456 */
+#  define costab2	MAD_F(0x0fec46d2)  /* 0.995184727 */
+#  define costab3	MAD_F(0x0fd3aac0)  /* 0.989176510 */
+#  define costab4	MAD_F(0x0fb14be8)  /* 0.980785280 */
+#  define costab5	MAD_F(0x0f853f7e)  /* 0.970031253 */
+#  define costab6	MAD_F(0x0f4fa0ab)  /* 0.956940336 */
+#  define costab7	MAD_F(0x0f109082)  /* 0.941544065 */
+#  define costab8	MAD_F(0x0ec835e8)  /* 0.923879533 */
+#  define costab9	MAD_F(0x0e76bd7a)  /* 0.903989293 */
+#  define costab10	MAD_F(0x0e1c5979)  /* 0.881921264 */
+#  define costab11	MAD_F(0x0db941a3)  /* 0.857728610 */
+#  define costab12	MAD_F(0x0d4db315)  /* 0.831469612 */
+#  define costab13	MAD_F(0x0cd9f024)  /* 0.803207531 */
+#  define costab14	MAD_F(0x0c5e4036)  /* 0.773010453 */
+#  define costab15	MAD_F(0x0bdaef91)  /* 0.740951125 */
+#  define costab16	MAD_F(0x0b504f33)  /* 0.707106781 */
+#  define costab17	MAD_F(0x0abeb49a)  /* 0.671558955 */
+#  define costab18	MAD_F(0x0a267993)  /* 0.634393284 */
+#  define costab19	MAD_F(0x0987fbfe)  /* 0.595699304 */
+#  define costab20	MAD_F(0x08e39d9d)  /* 0.555570233 */
+#  define costab21	MAD_F(0x0839c3cd)  /* 0.514102744 */
+#  define costab22	MAD_F(0x078ad74e)  /* 0.471396737 */
+#  define costab23	MAD_F(0x06d74402)  /* 0.427555093 */
+#  define costab24	MAD_F(0x061f78aa)  /* 0.382683432 */
+#  define costab25	MAD_F(0x0563e69d)  /* 0.336889853 */
+#  define costab26	MAD_F(0x04a5018c)  /* 0.290284677 */
+#  define costab27	MAD_F(0x03e33f2f)  /* 0.242980180 */
+#  define costab28	MAD_F(0x031f1708)  /* 0.195090322 */
+#  define costab29	MAD_F(0x0259020e)  /* 0.146730474 */
+#  define costab30	MAD_F(0x01917a6c)  /* 0.098017140 */
+#  define 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 * 2) - 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 * 2) - t49;
+
+  /*  5 */ hi[10][slot] = SHIFT(t68);
+
+  t132 = t100 + t101;
+  t133 = t102 + t103;
+
+  t104 = t132 + t133;
+
+  t82  = (t104 * 2) - t58;
+
+  /*  6 */ hi[ 9][slot] = SHIFT(t82);
+
+  t136 = t106 + t107;
+  t137 = t108 + t109;
+
+  t110 = t136 + t137;
+
+  t87  = (t110 * 2) - t67;
+
+  t77  = (t87 * 2) - 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) * 2) - t143);
+
+  t144 = MUL(t73 - t74, costab8);
+  t145 = MUL(t75 - t76, costab24);
+  t146 = t144 + t145;
+
+  t88  = (t146 * 2) - t77;
+
+  /*  9 */ hi[ 6][slot] = SHIFT(t88);
+
+  t148 = MUL(t78 - t79, costab8);
+  t149 = MUL(t80 - t81, costab24);
+  t150 = t148 + t149;
+
+  t105 = (t150 * 2) - t82;
+
+  /* 10 */ hi[ 5][slot] = SHIFT(t105);
+
+  t152 = MUL(t83 - t84, costab8);
+  t153 = MUL(t85 - t86, costab24);
+  t154 = t152 + t153;
+
+  t111 = (t154 * 2) - t87;
+
+  t99  = (t111 * 2) - t88;
+
+  /* 11 */ hi[ 4][slot] = SHIFT(t99);
+
+  t157 = MUL(t89 - t90, costab8);
+  t158 = MUL(t91 - t92, costab24);
+  t159 = t157 + t158;
+
+  t127 = (t159 * 2) - t93;
+
+  /* 12 */ hi[ 3][slot] = SHIFT(t127);
+
+  t160 = (MUL(t125 - t126, costab16) * 2) - t127;
+
+  /* 20 */ lo[ 4][slot] = SHIFT(t160);
+  /* 28 */ lo[12][slot] =
+	     SHIFT((((MUL(t157 - t158, costab16) * 2) - t159) * 2) - t160);
+
+  t161 = MUL(t94 - t95, costab8);
+  t162 = MUL(t96 - t97, costab24);
+  t163 = t161 + t162;
+
+  t130 = (t163 * 2) - t98;
+
+  t112 = (t130 * 2) - t99;
+
+  /* 13 */ hi[ 2][slot] = SHIFT(t112);
+
+  t164 = (MUL(t128 - t129, costab16) * 2) - t130;
+
+  t166 = MUL(t100 - t101, costab8);
+  t167 = MUL(t102 - t103, costab24);
+  t168 = t166 + t167;
+
+  t134 = (t168 * 2) - t104;
+
+  t120 = (t134 * 2) - t105;
+
+  /* 14 */ hi[ 1][slot] = SHIFT(t120);
+
+  t135 = (MUL(t118 - t119, costab16) * 2) - t120;
+
+  /* 18 */ lo[ 2][slot] = SHIFT(t135);
+
+  t169 = (MUL(t132 - t133, costab16) * 2) - t134;
+
+  t151 = (t169 * 2) - t135;
+
+  /* 22 */ lo[ 6][slot] = SHIFT(t151);
+
+  t170 = (((MUL(t148 - t149, costab16) * 2) - t150) * 2) - t151;
+
+  /* 26 */ lo[10][slot] = SHIFT(t170);
+  /* 30 */ lo[14][slot] =
+	     SHIFT((((((MUL(t166 - t167, costab16) * 2) -
+		       t168) * 2) - t169) * 2) - t170);
+
+  t171 = MUL(t106 - t107, costab8);
+  t172 = MUL(t108 - t109, costab24);
+  t173 = t171 + t172;
+
+  t138 = (t173 * 2) - t110;
+
+  t123 = (t138 * 2) - t111;
+
+  t139 = (MUL(t121 - t122, costab16) * 2) - t123;
+
+  t117 = (t123 * 2) - t112;
+
+  /* 15 */ hi[ 0][slot] = SHIFT(t117);
+
+  t124 = (MUL(t115 - t116, costab16) * 2) - t117;
+
+  /* 17 */ lo[ 1][slot] = SHIFT(t124);
+
+  t131 = (t139 * 2) - t124;
+
+  /* 19 */ lo[ 3][slot] = SHIFT(t131);
+
+  t140 = (t164 * 2) - t131;
+
+  /* 21 */ lo[ 5][slot] = SHIFT(t140);
+
+  t174 = (MUL(t136 - t137, costab16) * 2) - t138;
+
+  t155 = (t174 * 2) - t139;
+
+  t147 = (t155 * 2) - t140;
+
+  /* 23 */ lo[ 7][slot] = SHIFT(t147);
+
+  t156 = (((MUL(t144 - t145, costab16) * 2) - t146) * 2) - t147;
+
+  /* 25 */ lo[ 9][slot] = SHIFT(t156);
+
+  t175 = (((MUL(t152 - t153, costab16) * 2) - t154) * 2) - t155;
+
+  t165 = (t175 * 2) - t156;
+
+  /* 27 */ lo[11][slot] = SHIFT(t165);
+
+  t176 = (((((MUL(t161 - t162, costab16) * 2) -
+	     t163) * 2) - t164) * 2) - t165;
+
+  /* 29 */ lo[13][slot] = SHIFT(t176);
+  /* 31 */ lo[15][slot] =
+	     SHIFT((((((((MUL(t171 - t172, costab16) * 2) -
+			 t173) * 2) - t174) * 2) - t175) * 2) - 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 MLN(hi, lo)		((lo)  = -(lo))
+#  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 MLN(hi, lo)		MAD_F_MLN((hi), (lo))
+#  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.h"
+};
+
+# if defined(ASO_SYNTH)
+void synth_full(struct mad_synth *, struct mad_frame const *,
+		unsigned int, unsigned int);
+# else
+/*
+ * NAME:	synth->full()
+ * DESCRIPTION:	perform full frequency PCM synthesis
+ */
+static
+void synth_full(struct mad_synth *synth, struct mad_frame const *frame,
+		unsigned int nch, unsigned int ns)
+{
+  unsigned int phase, ch, s, sb, pe, po;
+  mad_fixed_t *pcm1, *pcm2, (*filter)[2][2][16][8];
+  mad_fixed_t const (*sbsample)[36][32];
+  register mad_fixed_t (*fe)[8], (*fx)[8], (*fo)[8];
+  register mad_fixed_t const (*Dptr)[32], *ptr;
+  register mad_fixed64hi_t hi;
+  register mad_fixed64lo_t lo;
+
+  for (ch = 0; ch < nch; ++ch) {
+    sbsample = &frame->sbsample[ch];
+    filter   = &synth->filter[ch];
+    phase    = synth->phase;
+    pcm1     = synth->pcm.samples[ch];
+
+    for (s = 0; s < ns; ++s) {
+      dct32((*sbsample)[s], phase >> 1,
+	    (*filter)[0][phase & 1], (*filter)[1][phase & 1]);
+
+      pe = phase & ~1;
+      po = ((phase - 1) & 0xf) | 1;
+
+      /* calculate 32 samples */
+
+      fe = &(*filter)[0][ phase & 1][0];
+      fx = &(*filter)[0][~phase & 1][0];
+      fo = &(*filter)[1][~phase & 1][0];
+
+      Dptr = &D[0];
+
+      ptr = *Dptr + po;
+      ML0(hi, lo, (*fx)[0], ptr[ 0]);
+      MLA(hi, lo, (*fx)[1], ptr[14]);
+      MLA(hi, lo, (*fx)[2], ptr[12]);
+      MLA(hi, lo, (*fx)[3], ptr[10]);
+      MLA(hi, lo, (*fx)[4], ptr[ 8]);
+      MLA(hi, lo, (*fx)[5], ptr[ 6]);
+      MLA(hi, lo, (*fx)[6], ptr[ 4]);
+      MLA(hi, lo, (*fx)[7], ptr[ 2]);
+      MLN(hi, lo);
+
+      ptr = *Dptr + pe;
+      MLA(hi, lo, (*fe)[0], ptr[ 0]);
+      MLA(hi, lo, (*fe)[1], ptr[14]);
+      MLA(hi, lo, (*fe)[2], ptr[12]);
+      MLA(hi, lo, (*fe)[3], ptr[10]);
+      MLA(hi, lo, (*fe)[4], ptr[ 8]);
+      MLA(hi, lo, (*fe)[5], ptr[ 6]);
+      MLA(hi, lo, (*fe)[6], ptr[ 4]);
+      MLA(hi, lo, (*fe)[7], ptr[ 2]);
+
+      *pcm1++ = SHIFT(MLZ(hi, lo));
+
+      pcm2 = pcm1 + 30;
+
+      for (sb = 1; sb < 16; ++sb) {
+	++fe;
+	++Dptr;
+
+	/* D[32 - sb][i] == -D[sb][31 - i] */
+
+	ptr = *Dptr + po;
+	ML0(hi, lo, (*fo)[0], ptr[ 0]);
+	MLA(hi, lo, (*fo)[1], ptr[14]);
+	MLA(hi, lo, (*fo)[2], ptr[12]);
+	MLA(hi, lo, (*fo)[3], ptr[10]);
+	MLA(hi, lo, (*fo)[4], ptr[ 8]);
+	MLA(hi, lo, (*fo)[5], ptr[ 6]);
+	MLA(hi, lo, (*fo)[6], ptr[ 4]);
+	MLA(hi, lo, (*fo)[7], ptr[ 2]);
+	MLN(hi, lo);
+
+	ptr = *Dptr + pe;
+	MLA(hi, lo, (*fe)[7], ptr[ 2]);
+	MLA(hi, lo, (*fe)[6], ptr[ 4]);
+	MLA(hi, lo, (*fe)[5], ptr[ 6]);
+	MLA(hi, lo, (*fe)[4], ptr[ 8]);
+	MLA(hi, lo, (*fe)[3], ptr[10]);
+	MLA(hi, lo, (*fe)[2], ptr[12]);
+	MLA(hi, lo, (*fe)[1], ptr[14]);
+	MLA(hi, lo, (*fe)[0], ptr[ 0]);
+
+	*pcm1++ = SHIFT(MLZ(hi, lo));
+
+	ptr = *Dptr - pe;
+	ML0(hi, lo, (*fe)[0], ptr[31 - 16]);
+	MLA(hi, lo, (*fe)[1], ptr[31 - 14]);
+	MLA(hi, lo, (*fe)[2], ptr[31 - 12]);
+	MLA(hi, lo, (*fe)[3], ptr[31 - 10]);
+	MLA(hi, lo, (*fe)[4], ptr[31 -  8]);
+	MLA(hi, lo, (*fe)[5], ptr[31 -  6]);
+	MLA(hi, lo, (*fe)[6], ptr[31 -  4]);
+	MLA(hi, lo, (*fe)[7], ptr[31 -  2]);
+
+	ptr = *Dptr - po;
+	MLA(hi, lo, (*fo)[7], ptr[31 -  2]);
+	MLA(hi, lo, (*fo)[6], ptr[31 -  4]);
+	MLA(hi, lo, (*fo)[5], ptr[31 -  6]);
+	MLA(hi, lo, (*fo)[4], ptr[31 -  8]);
+	MLA(hi, lo, (*fo)[3], ptr[31 - 10]);
+	MLA(hi, lo, (*fo)[2], ptr[31 - 12]);
+	MLA(hi, lo, (*fo)[1], ptr[31 - 14]);
+	MLA(hi, lo, (*fo)[0], ptr[31 - 16]);
+
+	*pcm2-- = SHIFT(MLZ(hi, lo));
+
+	++fo;
+      }
+
+      ++Dptr;
+
+      ptr = *Dptr + po;
+      ML0(hi, lo, (*fo)[0], ptr[ 0]);
+      MLA(hi, lo, (*fo)[1], ptr[14]);
+      MLA(hi, lo, (*fo)[2], ptr[12]);
+      MLA(hi, lo, (*fo)[3], ptr[10]);
+      MLA(hi, lo, (*fo)[4], ptr[ 8]);
+      MLA(hi, lo, (*fo)[5], ptr[ 6]);
+      MLA(hi, lo, (*fo)[6], ptr[ 4]);
+      MLA(hi, lo, (*fo)[7], ptr[ 2]);
+
+      *pcm1 = SHIFT(-MLZ(hi, lo));
+      pcm1 += 16;
+
+      phase = (phase + 1) % 16;
+    }
+  }
+}
+# endif
+
+/*
+ * NAME:	synth->half()
+ * DESCRIPTION:	perform half frequency PCM synthesis
+ */
+static
+void synth_half(struct mad_synth *synth, struct mad_frame const *frame,
+		unsigned int nch, unsigned int ns)
+{
+  unsigned int phase, ch, s, sb, pe, po;
+  mad_fixed_t *pcm1, *pcm2, (*filter)[2][2][16][8];
+  mad_fixed_t const (*sbsample)[36][32];
+  register mad_fixed_t (*fe)[8], (*fx)[8], (*fo)[8];
+  register mad_fixed_t const (*Dptr)[32], *ptr;
+  register mad_fixed64hi_t hi;
+  register mad_fixed64lo_t lo;
+
+  for (ch = 0; ch < nch; ++ch) {
+    sbsample = &frame->sbsample[ch];
+    filter   = &synth->filter[ch];
+    phase    = synth->phase;
+    pcm1     = synth->pcm.samples[ch];
+
+    for (s = 0; s < ns; ++s) {
+      dct32((*sbsample)[s], phase >> 1,
+	    (*filter)[0][phase & 1], (*filter)[1][phase & 1]);
+
+      pe = phase & ~1;
+      po = ((phase - 1) & 0xf) | 1;
+
+      /* calculate 16 samples */
+
+      fe = &(*filter)[0][ phase & 1][0];
+      fx = &(*filter)[0][~phase & 1][0];
+      fo = &(*filter)[1][~phase & 1][0];
+
+      Dptr = &D[0];
+
+      ptr = *Dptr + po;
+      ML0(hi, lo, (*fx)[0], ptr[ 0]);
+      MLA(hi, lo, (*fx)[1], ptr[14]);
+      MLA(hi, lo, (*fx)[2], ptr[12]);
+      MLA(hi, lo, (*fx)[3], ptr[10]);
+      MLA(hi, lo, (*fx)[4], ptr[ 8]);
+      MLA(hi, lo, (*fx)[5], ptr[ 6]);
+      MLA(hi, lo, (*fx)[6], ptr[ 4]);
+      MLA(hi, lo, (*fx)[7], ptr[ 2]);
+      MLN(hi, lo);
+
+      ptr = *Dptr + pe;
+      MLA(hi, lo, (*fe)[0], ptr[ 0]);
+      MLA(hi, lo, (*fe)[1], ptr[14]);
+      MLA(hi, lo, (*fe)[2], ptr[12]);
+      MLA(hi, lo, (*fe)[3], ptr[10]);
+      MLA(hi, lo, (*fe)[4], ptr[ 8]);
+      MLA(hi, lo, (*fe)[5], ptr[ 6]);
+      MLA(hi, lo, (*fe)[6], ptr[ 4]);
+      MLA(hi, lo, (*fe)[7], ptr[ 2]);
+
+      *pcm1++ = SHIFT(MLZ(hi, lo));
+
+      pcm2 = pcm1 + 14;
+
+      for (sb = 1; sb < 16; ++sb) {
+	++fe;
+	++Dptr;
+
+	/* D[32 - sb][i] == -D[sb][31 - i] */
+
+	if (!(sb & 1)) {
+	  ptr = *Dptr + po;
+	  ML0(hi, lo, (*fo)[0], ptr[ 0]);
+	  MLA(hi, lo, (*fo)[1], ptr[14]);
+	  MLA(hi, lo, (*fo)[2], ptr[12]);
+	  MLA(hi, lo, (*fo)[3], ptr[10]);
+	  MLA(hi, lo, (*fo)[4], ptr[ 8]);
+	  MLA(hi, lo, (*fo)[5], ptr[ 6]);
+	  MLA(hi, lo, (*fo)[6], ptr[ 4]);
+	  MLA(hi, lo, (*fo)[7], ptr[ 2]);
+	  MLN(hi, lo);
+
+	  ptr = *Dptr + pe;
+	  MLA(hi, lo, (*fe)[7], ptr[ 2]);
+	  MLA(hi, lo, (*fe)[6], ptr[ 4]);
+	  MLA(hi, lo, (*fe)[5], ptr[ 6]);
+	  MLA(hi, lo, (*fe)[4], ptr[ 8]);
+	  MLA(hi, lo, (*fe)[3], ptr[10]);
+	  MLA(hi, lo, (*fe)[2], ptr[12]);
+	  MLA(hi, lo, (*fe)[1], ptr[14]);
+	  MLA(hi, lo, (*fe)[0], ptr[ 0]);
+
+	  *pcm1++ = SHIFT(MLZ(hi, lo));
+
+	  ptr = *Dptr - po;
+	  ML0(hi, lo, (*fo)[7], ptr[31 -  2]);
+	  MLA(hi, lo, (*fo)[6], ptr[31 -  4]);
+	  MLA(hi, lo, (*fo)[5], ptr[31 -  6]);
+	  MLA(hi, lo, (*fo)[4], ptr[31 -  8]);
+	  MLA(hi, lo, (*fo)[3], ptr[31 - 10]);
+	  MLA(hi, lo, (*fo)[2], ptr[31 - 12]);
+	  MLA(hi, lo, (*fo)[1], ptr[31 - 14]);
+	  MLA(hi, lo, (*fo)[0], ptr[31 - 16]);
+
+	  ptr = *Dptr - pe;
+	  MLA(hi, lo, (*fe)[0], ptr[31 - 16]);
+	  MLA(hi, lo, (*fe)[1], ptr[31 - 14]);
+	  MLA(hi, lo, (*fe)[2], ptr[31 - 12]);
+	  MLA(hi, lo, (*fe)[3], ptr[31 - 10]);
+	  MLA(hi, lo, (*fe)[4], ptr[31 -  8]);
+	  MLA(hi, lo, (*fe)[5], ptr[31 -  6]);
+	  MLA(hi, lo, (*fe)[6], ptr[31 -  4]);
+	  MLA(hi, lo, (*fe)[7], ptr[31 -  2]);
+
+	  *pcm2-- = SHIFT(MLZ(hi, lo));
+	}
+
+	++fo;
+      }
+
+      ++Dptr;
+
+      ptr = *Dptr + po;
+      ML0(hi, lo, (*fo)[0], ptr[ 0]);
+      MLA(hi, lo, (*fo)[1], ptr[14]);
+      MLA(hi, lo, (*fo)[2], ptr[12]);
+      MLA(hi, lo, (*fo)[3], ptr[10]);
+      MLA(hi, lo, (*fo)[4], ptr[ 8]);
+      MLA(hi, lo, (*fo)[5], ptr[ 6]);
+      MLA(hi, lo, (*fo)[6], ptr[ 4]);
+      MLA(hi, lo, (*fo)[7], ptr[ 2]);
+
+      *pcm1 = SHIFT(-MLZ(hi, lo));
+      pcm1 += 8;
+
+      phase = (phase + 1) % 16;
+    }
+  }
+}
+
+/*
+ * NAME:	synth->frame()
+ * DESCRIPTION:	perform PCM synthesis of frame subband samples
+ */
+void mad_synth_frame(struct mad_synth *synth, struct mad_frame const *frame)
+{
+  unsigned int nch, ns;
+  void (*synth_frame)(struct mad_synth *, struct mad_frame const *,
+		      unsigned int, unsigned int);
+
+  nch = MAD_NCHANNELS(&frame->header);
+  ns  = MAD_NSBSAMPLES(&frame->header);
+
+  synth->pcm.samplerate = frame->header.samplerate;
+  synth->pcm.channels   = nch;
+  synth->pcm.length     = 32 * ns;
+
+  synth_frame = synth_full;
+
+  if (frame->options & MAD_OPTION_HALFSAMPLERATE) {
+    synth->pcm.samplerate /= 2;
+    synth->pcm.length     /= 2;
+
+    synth_frame = synth_half;
+  }
+
+  synth_frame(synth, frame, nch, ns);
+
+  synth->phase = (synth->phase + ns) % 16;
+}