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authorMaurus Cuelenaere <mcuelenaere@gmail.com>2009-07-04 13:17:58 +0000
committerMaurus Cuelenaere <mcuelenaere@gmail.com>2009-07-04 13:17:58 +0000
commitc3bc8fda8019c69c1bf9cd74539df07db527eebc (patch)
tree7bab3843bfe24cbdbb5153baba12827bcd755a72 /apps/fixedpoint.c
parent861b8d8606059de2f7527e9429dc109e8b89c03c (diff)
downloadrockbox-c3bc8fda8019c69c1bf9cd74539df07db527eebc.tar.gz
rockbox-c3bc8fda8019c69c1bf9cd74539df07db527eebc.zip
Revert "Consolidate all fixed point math routines in one library (FS#10400) by Jeffrey Goode"
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21635 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'apps/fixedpoint.c')
-rw-r--r--apps/fixedpoint.c440
1 files changed, 0 insertions, 440 deletions
diff --git a/apps/fixedpoint.c b/apps/fixedpoint.c
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-/***************************************************************************
- * __________ __ ___.
- * Open \______ \ ____ ____ | | _\_ |__ _______ ___
- * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
- * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
- * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
- * \/ \/ \/ \/ \/
- * $Id$
- *
- * Copyright (C) 2006 Jens Arnold
- *
- * Fixed point library for plugins
- *
- * 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
- * KIND, either express or implied.
- *
- ****************************************************************************/
-
-#include "fixedpoint.h"
-#include <stdlib.h>
-#include <stdbool.h>
-
-#ifndef BIT_N
-#define BIT_N(n) (1U << (n))
-#endif
-
-/** TAKEN FROM ORIGINAL fixedpoint.h */
-/* Inverse gain of circular cordic rotation in s0.31 format. */
-static const long cordic_circular_gain = 0xb2458939; /* 0.607252929 */
-
-/* Table of values of atan(2^-i) in 0.32 format fractions of pi where pi = 0xffffffff / 2 */
-static const unsigned long atan_table[] = {
- 0x1fffffff, /* +0.785398163 (or pi/4) */
- 0x12e4051d, /* +0.463647609 */
- 0x09fb385b, /* +0.244978663 */
- 0x051111d4, /* +0.124354995 */
- 0x028b0d43, /* +0.062418810 */
- 0x0145d7e1, /* +0.031239833 */
- 0x00a2f61e, /* +0.015623729 */
- 0x00517c55, /* +0.007812341 */
- 0x0028be53, /* +0.003906230 */
- 0x00145f2e, /* +0.001953123 */
- 0x000a2f98, /* +0.000976562 */
- 0x000517cc, /* +0.000488281 */
- 0x00028be6, /* +0.000244141 */
- 0x000145f3, /* +0.000122070 */
- 0x0000a2f9, /* +0.000061035 */
- 0x0000517c, /* +0.000030518 */
- 0x000028be, /* +0.000015259 */
- 0x0000145f, /* +0.000007629 */
- 0x00000a2f, /* +0.000003815 */
- 0x00000517, /* +0.000001907 */
- 0x0000028b, /* +0.000000954 */
- 0x00000145, /* +0.000000477 */
- 0x000000a2, /* +0.000000238 */
- 0x00000051, /* +0.000000119 */
- 0x00000028, /* +0.000000060 */
- 0x00000014, /* +0.000000030 */
- 0x0000000a, /* +0.000000015 */
- 0x00000005, /* +0.000000007 */
- 0x00000002, /* +0.000000004 */
- 0x00000001, /* +0.000000002 */
- 0x00000000, /* +0.000000001 */
- 0x00000000, /* +0.000000000 */
-};
-
-/* Precalculated sine and cosine * 16384 (2^14) (fixed point 18.14) */
-static const short sin_table[91] =
-{
- 0, 285, 571, 857, 1142, 1427, 1712, 1996, 2280, 2563,
- 2845, 3126, 3406, 3685, 3963, 4240, 4516, 4790, 5062, 5334,
- 5603, 5871, 6137, 6401, 6663, 6924, 7182, 7438, 7691, 7943,
- 8191, 8438, 8682, 8923, 9161, 9397, 9630, 9860, 10086, 10310,
- 10531, 10748, 10963, 11173, 11381, 11585, 11785, 11982, 12175, 12365,
- 12550, 12732, 12910, 13084, 13254, 13420, 13582, 13740, 13894, 14043,
- 14188, 14329, 14466, 14598, 14725, 14848, 14967, 15081, 15190, 15295,
- 15395, 15491, 15582, 15668, 15749, 15825, 15897, 15964, 16025, 16082,
- 16135, 16182, 16224, 16261, 16294, 16321, 16344, 16361, 16374, 16381,
- 16384
-};
-
-/**
- * Implements sin and cos using CORDIC rotation.
- *
- * @param phase has range from 0 to 0xffffffff, representing 0 and
- * 2*pi respectively.
- * @param cos return address for cos
- * @return sin of phase, value is a signed value from LONG_MIN to LONG_MAX,
- * representing -1 and 1 respectively.
- */
-long fsincos(unsigned long phase, long *cos)
-{
- int32_t x, x1, y, y1;
- unsigned long z, z1;
- int i;
-
- /* Setup initial vector */
- x = cordic_circular_gain;
- y = 0;
- z = phase;
-
- /* The phase has to be somewhere between 0..pi for this to work right */
- if (z < 0xffffffff / 4) {
- /* z in first quadrant, z += pi/2 to correct */
- x = -x;
- z += 0xffffffff / 4;
- } else if (z < 3 * (0xffffffff / 4)) {
- /* z in third quadrant, z -= pi/2 to correct */
- z -= 0xffffffff / 4;
- } else {
- /* z in fourth quadrant, z -= 3pi/2 to correct */
- x = -x;
- z -= 3 * (0xffffffff / 4);
- }
-
- /* Each iteration adds roughly 1-bit of extra precision */
- for (i = 0; i < 31; i++) {
- x1 = x >> i;
- y1 = y >> i;
- z1 = atan_table[i];
-
- /* Decided which direction to rotate vector. Pivot point is pi/2 */
- if (z >= 0xffffffff / 4) {
- x -= y1;
- y += x1;
- z -= z1;
- } else {
- x += y1;
- y -= x1;
- z += z1;
- }
- }
-
- if (cos)
- *cos = x;
-
- return y;
-}
-
-/**
- * Fixed point square root via Newton-Raphson.
- * @param x square root argument.
- * @param fracbits specifies number of fractional bits in argument.
- * @return Square root of argument in same fixed point format as input.
- *
- * This routine has been modified to run longer for greater precision,
- * but cuts calculation short if the answer is reached sooner. In
- * general, the closer x is to 1, the quicker the calculation.
- */
-long fsqrt(long x, unsigned int fracbits)
-{
- long b = x/2 + BIT_N(fracbits); /* initial approximation */
- long c;
- unsigned n;
- const unsigned iterations = 8;
-
- for (n = 0; n < iterations; ++n)
- {
- c = DIV64(x, b, fracbits);
- if (c == b) break;
- b = (b + c)/2;
- }
-
- return b;
-}
-
-/**
- * Fixed point sinus using a lookup table
- * don't forget to divide the result by 16384 to get the actual sinus value
- * @param val sinus argument in degree
- * @return sin(val)*16384
- */
-long sin_int(int val)
-{
- val = (val+360)%360;
- if (val < 181)
- {
- if (val < 91)/* phase 0-90 degree */
- return (long)sin_table[val];
- else/* phase 91-180 degree */
- return (long)sin_table[180-val];
- }
- else
- {
- if (val < 271)/* phase 181-270 degree */
- return -(long)sin_table[val-180];
- else/* phase 270-359 degree */
- return -(long)sin_table[360-val];
- }
- return 0;
-}
-
-/**
- * Fixed point cosinus using a lookup table
- * don't forget to divide the result by 16384 to get the actual cosinus value
- * @param val sinus argument in degree
- * @return cos(val)*16384
- */
-long cos_int(int val)
-{
- val = (val+360)%360;
- if (val < 181)
- {
- if (val < 91)/* phase 0-90 degree */
- return (long)sin_table[90-val];
- else/* phase 91-180 degree */
- return -(long)sin_table[val-90];
- }
- else
- {
- if (val < 271)/* phase 181-270 degree */
- return -(long)sin_table[270-val];
- else/* phase 270-359 degree */
- return (long)sin_table[val-270];
- }
- return 0;
-}
-
-/**
- * Fixed-point natural log
- * taken from http://www.quinapalus.com/efunc.html
- * "The code assumes integers are at least 32 bits long. The (positive)
- * argument and the result of the function are both expressed as fixed-point
- * values with 16 fractional bits, although intermediates are kept with 28
- * bits of precision to avoid loss of accuracy during shifts."
- */
-
-long flog(int x) {
- long t,y;
-
- y=0xa65af;
- if(x<0x00008000) x<<=16, y-=0xb1721;
- if(x<0x00800000) x<<= 8, y-=0x58b91;
- if(x<0x08000000) x<<= 4, y-=0x2c5c8;
- if(x<0x20000000) x<<= 2, y-=0x162e4;
- if(x<0x40000000) x<<= 1, y-=0x0b172;
- t=x+(x>>1); if((t&0x80000000)==0) x=t,y-=0x067cd;
- t=x+(x>>2); if((t&0x80000000)==0) x=t,y-=0x03920;
- t=x+(x>>3); if((t&0x80000000)==0) x=t,y-=0x01e27;
- t=x+(x>>4); if((t&0x80000000)==0) x=t,y-=0x00f85;
- t=x+(x>>5); if((t&0x80000000)==0) x=t,y-=0x007e1;
- t=x+(x>>6); if((t&0x80000000)==0) x=t,y-=0x003f8;
- t=x+(x>>7); if((t&0x80000000)==0) x=t,y-=0x001fe;
- x=0x80000000-x;
- y-=x>>15;
- return y;
-}
-
-/** MODIFIED FROM replaygain.c */
-/* These math routines have 64-bit internal precision to avoid overflows.
- * Arguments and return values are 32-bit (long) precision.
- */
-
-#define FP_MUL64(x, y) (((x) * (y)) >> (fracbits))
-#define FP_DIV64(x, y) (((x) << (fracbits)) / (y))
-
-static long long fp_exp10(long long x, unsigned int fracbits);
-static long long fp_log10(long long n, unsigned int fracbits);
-
-/* constants in fixed point format, 28 fractional bits */
-#define FP28_LN2 (186065279LL) /* ln(2) */
-#define FP28_LN2_INV (387270501LL) /* 1/ln(2) */
-#define FP28_EXP_ZERO (44739243LL) /* 1/6 */
-#define FP28_EXP_ONE (-745654LL) /* -1/360 */
-#define FP28_EXP_TWO (12428LL) /* 1/21600 */
-#define FP28_LN10 (618095479LL) /* ln(10) */
-#define FP28_LOG10OF2 (80807124LL) /* log10(2) */
-
-#define TOL_BITS 2 /* log calculation tolerance */
-
-
-/* The fpexp10 fixed point math routine is based
- * on oMathFP by Dan Carter (http://orbisstudios.com).
- */
-
-/** FIXED POINT EXP10
- * Return 10^x as FP integer. Argument is FP integer.
- */
-static long long fp_exp10(long long x, unsigned int fracbits)
-{
- long long k;
- long long z;
- long long R;
- long long xp;
-
- /* scale constants */
- const long long fp_one = (1 << fracbits);
- const long long fp_half = (1 << (fracbits - 1));
- const long long fp_two = (2 << fracbits);
- const long long fp_mask = (fp_one - 1);
- const long long fp_ln2_inv = (FP28_LN2_INV >> (28 - fracbits));
- const long long fp_ln2 = (FP28_LN2 >> (28 - fracbits));
- const long long fp_ln10 = (FP28_LN10 >> (28 - fracbits));
- const long long fp_exp_zero = (FP28_EXP_ZERO >> (28 - fracbits));
- const long long fp_exp_one = (FP28_EXP_ONE >> (28 - fracbits));
- const long long fp_exp_two = (FP28_EXP_TWO >> (28 - fracbits));
-
- /* exp(0) = 1 */
- if (x == 0)
- {
- return fp_one;
- }
-
- /* convert from base 10 to base e */
- x = FP_MUL64(x, fp_ln10);
-
- /* calculate exp(x) */
- k = (FP_MUL64(abs(x), fp_ln2_inv) + fp_half) & ~fp_mask;
-
- if (x < 0)
- {
- k = -k;
- }
-
- x -= FP_MUL64(k, fp_ln2);
- z = FP_MUL64(x, x);
- R = fp_two + FP_MUL64(z, fp_exp_zero + FP_MUL64(z, fp_exp_one
- + FP_MUL64(z, fp_exp_two)));
- xp = fp_one + FP_DIV64(FP_MUL64(fp_two, x), R - x);
-
- if (k < 0)
- {
- k = fp_one >> (-k >> fracbits);
- }
- else
- {
- k = fp_one << (k >> fracbits);
- }
-
- return FP_MUL64(k, xp);
-}
-
-
-/** FIXED POINT LOG10
- * Return log10(x) as FP integer. Argument is FP integer.
- */
-static long long fp_log10(long long n, unsigned int fracbits)
-{
- /* Calculate log2 of argument */
-
- long long log2, frac;
- const long long fp_one = (1 << fracbits);
- const long long fp_two = (2 << fracbits);
- const long tolerance = (1 << ((fracbits / 2) + 2));
-
- if (n <=0) return FP_NEGINF;
- log2 = 0;
-
- /* integer part */
- while (n < fp_one)
- {
- log2 -= fp_one;
- n <<= 1;
- }
- while (n >= fp_two)
- {
- log2 += fp_one;
- n >>= 1;
- }
-
- /* fractional part */
- frac = fp_one;
- while (frac > tolerance)
- {
- frac >>= 1;
- n = FP_MUL64(n, n);
- if (n >= fp_two)
- {
- n >>= 1;
- log2 += frac;
- }
- }
-
- /* convert log2 to log10 */
- return FP_MUL64(log2, (FP28_LOG10OF2 >> (28 - fracbits)));
-}
-
-
-/** CONVERT FACTOR TO DECIBELS */
-long fp_decibels(unsigned long factor, unsigned int fracbits)
-{
- long long decibels;
- long long f = (long long)factor;
- bool neg;
-
- /* keep factor in signed long range */
- if (f >= (1LL << 31))
- f = (1LL << 31) - 1;
-
- /* decibels = 20 * log10(factor) */
- decibels = FP_MUL64((20LL << fracbits), fp_log10(f, fracbits));
-
- /* keep result in signed long range */
- if ((neg = (decibels < 0)))
- decibels = -decibels;
- if (decibels >= (1LL << 31))
- return neg ? FP_NEGINF : FP_INF;
-
- return neg ? (long)-decibels : (long)decibels;
-}
-
-
-/** CONVERT DECIBELS TO FACTOR */
-long fp_factor(long decibels, unsigned int fracbits)
-{
- bool neg;
- long long factor;
- long long db = (long long)decibels;
-
- /* if decibels is 0, factor is 1 */
- if (db == 0)
- return (1L << fracbits);
-
- /* calculate for positive decibels only */
- if ((neg = (db < 0)))
- db = -db;
-
- /* factor = 10 ^ (decibels / 20) */
- factor = fp_exp10(FP_DIV64(db, (20LL << fracbits)), fracbits);
-
- /* keep result in signed long range, return 0 if very small */
- if (factor >= (1LL << 31))
- {
- if (neg)
- return 0;
- else
- return FP_INF;
- }
-
- /* if negative argument, factor is 1 / result */
- if (neg)
- factor = FP_DIV64((1LL << fracbits), factor);
-
- return (long)factor;
-}