Take 2 at 'Consolidate all fixed point math routines in one library' (FS#10400) by Jeffrey Goode

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21664 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 1 insertions, 238 deletions

diff --git a/apps/plugins/lib/fixedpoint.c b/apps/plugins/lib/fixedpoint.c
index 0ae2cded69..352e246673 100644
--- a/apps/plugins/lib/fixedpoint.c
+++ b/apps/plugins/lib/fixedpoint.c
@@ -1,238 +1 @@
-/***************************************************************************
- *             __________               __   ___.
- *   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 <inttypes.h>
-#include "plugin.h"
-#include "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 a square root argument.
- * @param fracbits specifies number of fractional bits in argument.
- * @return Square root of argument in same fixed point format as input. 
- */
-long fsqrt(long a, unsigned int fracbits)
-{
-    long b = a/2 + BIT_N(fracbits); /* initial approximation */
-    unsigned n;
-    const unsigned iterations = 4;
-    
-    for (n = 0; n < iterations; ++n)
-        b = (b + (long)(((long long)(a) << fracbits)/b))/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;
-}
+#include "../../fixedpoint.c"