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author | Maurus Cuelenaere <mcuelenaere@gmail.com> | 2009-07-04 13:17:58 +0000 |
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committer | Maurus Cuelenaere <mcuelenaere@gmail.com> | 2009-07-04 13:17:58 +0000 |
commit | c3bc8fda8019c69c1bf9cd74539df07db527eebc (patch) | |
tree | 7bab3843bfe24cbdbb5153baba12827bcd755a72 /apps/fixedpoint.c | |
parent | 861b8d8606059de2f7527e9429dc109e8b89c03c (diff) | |
download | rockbox-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.c | 440 |
1 files changed, 0 insertions, 440 deletions
diff --git a/apps/fixedpoint.c b/apps/fixedpoint.c deleted file mode 100644 index 7738dc123e..0000000000 --- a/apps/fixedpoint.c +++ /dev/null | |||
@@ -1,440 +0,0 @@ | |||
1 | /*************************************************************************** | ||
2 | * __________ __ ___. | ||
3 | * Open \______ \ ____ ____ | | _\_ |__ _______ ___ | ||
4 | * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / | ||
5 | * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < | ||
6 | * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ | ||
7 | * \/ \/ \/ \/ \/ | ||
8 | * $Id$ | ||
9 | * | ||
10 | * Copyright (C) 2006 Jens Arnold | ||
11 | * | ||
12 | * Fixed point library for plugins | ||
13 | * | ||
14 | * This program is free software; you can redistribute it and/or | ||
15 | * modify it under the terms of the GNU General Public License | ||
16 | * as published by the Free Software Foundation; either version 2 | ||
17 | * of the License, or (at your option) any later version. | ||
18 | * | ||
19 | * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY | ||
20 | * KIND, either express or implied. | ||
21 | * | ||
22 | ****************************************************************************/ | ||
23 | |||
24 | #include "fixedpoint.h" | ||
25 | #include <stdlib.h> | ||
26 | #include <stdbool.h> | ||
27 | |||
28 | #ifndef BIT_N | ||
29 | #define BIT_N(n) (1U << (n)) | ||
30 | #endif | ||
31 | |||
32 | /** TAKEN FROM ORIGINAL fixedpoint.h */ | ||
33 | /* Inverse gain of circular cordic rotation in s0.31 format. */ | ||
34 | static const long cordic_circular_gain = 0xb2458939; /* 0.607252929 */ | ||
35 | |||
36 | /* Table of values of atan(2^-i) in 0.32 format fractions of pi where pi = 0xffffffff / 2 */ | ||
37 | static const unsigned long atan_table[] = { | ||
38 | 0x1fffffff, /* +0.785398163 (or pi/4) */ | ||
39 | 0x12e4051d, /* +0.463647609 */ | ||
40 | 0x09fb385b, /* +0.244978663 */ | ||
41 | 0x051111d4, /* +0.124354995 */ | ||
42 | 0x028b0d43, /* +0.062418810 */ | ||
43 | 0x0145d7e1, /* +0.031239833 */ | ||
44 | 0x00a2f61e, /* +0.015623729 */ | ||
45 | 0x00517c55, /* +0.007812341 */ | ||
46 | 0x0028be53, /* +0.003906230 */ | ||
47 | 0x00145f2e, /* +0.001953123 */ | ||
48 | 0x000a2f98, /* +0.000976562 */ | ||
49 | 0x000517cc, /* +0.000488281 */ | ||
50 | 0x00028be6, /* +0.000244141 */ | ||
51 | 0x000145f3, /* +0.000122070 */ | ||
52 | 0x0000a2f9, /* +0.000061035 */ | ||
53 | 0x0000517c, /* +0.000030518 */ | ||
54 | 0x000028be, /* +0.000015259 */ | ||
55 | 0x0000145f, /* +0.000007629 */ | ||
56 | 0x00000a2f, /* +0.000003815 */ | ||
57 | 0x00000517, /* +0.000001907 */ | ||
58 | 0x0000028b, /* +0.000000954 */ | ||
59 | 0x00000145, /* +0.000000477 */ | ||
60 | 0x000000a2, /* +0.000000238 */ | ||
61 | 0x00000051, /* +0.000000119 */ | ||
62 | 0x00000028, /* +0.000000060 */ | ||
63 | 0x00000014, /* +0.000000030 */ | ||
64 | 0x0000000a, /* +0.000000015 */ | ||
65 | 0x00000005, /* +0.000000007 */ | ||
66 | 0x00000002, /* +0.000000004 */ | ||
67 | 0x00000001, /* +0.000000002 */ | ||
68 | 0x00000000, /* +0.000000001 */ | ||
69 | 0x00000000, /* +0.000000000 */ | ||
70 | }; | ||
71 | |||
72 | /* Precalculated sine and cosine * 16384 (2^14) (fixed point 18.14) */ | ||
73 | static const short sin_table[91] = | ||
74 | { | ||
75 | 0, 285, 571, 857, 1142, 1427, 1712, 1996, 2280, 2563, | ||
76 | 2845, 3126, 3406, 3685, 3963, 4240, 4516, 4790, 5062, 5334, | ||
77 | 5603, 5871, 6137, 6401, 6663, 6924, 7182, 7438, 7691, 7943, | ||
78 | 8191, 8438, 8682, 8923, 9161, 9397, 9630, 9860, 10086, 10310, | ||
79 | 10531, 10748, 10963, 11173, 11381, 11585, 11785, 11982, 12175, 12365, | ||
80 | 12550, 12732, 12910, 13084, 13254, 13420, 13582, 13740, 13894, 14043, | ||
81 | 14188, 14329, 14466, 14598, 14725, 14848, 14967, 15081, 15190, 15295, | ||
82 | 15395, 15491, 15582, 15668, 15749, 15825, 15897, 15964, 16025, 16082, | ||
83 | 16135, 16182, 16224, 16261, 16294, 16321, 16344, 16361, 16374, 16381, | ||
84 | 16384 | ||
85 | }; | ||
86 | |||
87 | /** | ||
88 | * Implements sin and cos using CORDIC rotation. | ||
89 | * | ||
90 | * @param phase has range from 0 to 0xffffffff, representing 0 and | ||
91 | * 2*pi respectively. | ||
92 | * @param cos return address for cos | ||
93 | * @return sin of phase, value is a signed value from LONG_MIN to LONG_MAX, | ||
94 | * representing -1 and 1 respectively. | ||
95 | */ | ||
96 | long fsincos(unsigned long phase, long *cos) | ||
97 | { | ||
98 | int32_t x, x1, y, y1; | ||
99 | unsigned long z, z1; | ||
100 | int i; | ||
101 | |||
102 | /* Setup initial vector */ | ||
103 | x = cordic_circular_gain; | ||
104 | y = 0; | ||
105 | z = phase; | ||
106 | |||
107 | /* The phase has to be somewhere between 0..pi for this to work right */ | ||
108 | if (z < 0xffffffff / 4) { | ||
109 | /* z in first quadrant, z += pi/2 to correct */ | ||
110 | x = -x; | ||
111 | z += 0xffffffff / 4; | ||
112 | } else if (z < 3 * (0xffffffff / 4)) { | ||
113 | /* z in third quadrant, z -= pi/2 to correct */ | ||
114 | z -= 0xffffffff / 4; | ||
115 | } else { | ||
116 | /* z in fourth quadrant, z -= 3pi/2 to correct */ | ||
117 | x = -x; | ||
118 | z -= 3 * (0xffffffff / 4); | ||
119 | } | ||
120 | |||
121 | /* Each iteration adds roughly 1-bit of extra precision */ | ||
122 | for (i = 0; i < 31; i++) { | ||
123 | x1 = x >> i; | ||
124 | y1 = y >> i; | ||
125 | z1 = atan_table[i]; | ||
126 | |||
127 | /* Decided which direction to rotate vector. Pivot point is pi/2 */ | ||
128 | if (z >= 0xffffffff / 4) { | ||
129 | x -= y1; | ||
130 | y += x1; | ||
131 | z -= z1; | ||
132 | } else { | ||
133 | x += y1; | ||
134 | y -= x1; | ||
135 | z += z1; | ||
136 | } | ||
137 | } | ||
138 | |||
139 | if (cos) | ||
140 | *cos = x; | ||
141 | |||
142 | return y; | ||
143 | } | ||
144 | |||
145 | /** | ||
146 | * Fixed point square root via Newton-Raphson. | ||
147 | * @param x square root argument. | ||
148 | * @param fracbits specifies number of fractional bits in argument. | ||
149 | * @return Square root of argument in same fixed point format as input. | ||
150 | * | ||
151 | * This routine has been modified to run longer for greater precision, | ||
152 | * but cuts calculation short if the answer is reached sooner. In | ||
153 | * general, the closer x is to 1, the quicker the calculation. | ||
154 | */ | ||
155 | long fsqrt(long x, unsigned int fracbits) | ||
156 | { | ||
157 | long b = x/2 + BIT_N(fracbits); /* initial approximation */ | ||
158 | long c; | ||
159 | unsigned n; | ||
160 | const unsigned iterations = 8; | ||
161 | |||
162 | for (n = 0; n < iterations; ++n) | ||
163 | { | ||
164 | c = DIV64(x, b, fracbits); | ||
165 | if (c == b) break; | ||
166 | b = (b + c)/2; | ||
167 | } | ||
168 | |||
169 | return b; | ||
170 | } | ||
171 | |||
172 | /** | ||
173 | * Fixed point sinus using a lookup table | ||
174 | * don't forget to divide the result by 16384 to get the actual sinus value | ||
175 | * @param val sinus argument in degree | ||
176 | * @return sin(val)*16384 | ||
177 | */ | ||
178 | long sin_int(int val) | ||
179 | { | ||
180 | val = (val+360)%360; | ||
181 | if (val < 181) | ||
182 | { | ||
183 | if (val < 91)/* phase 0-90 degree */ | ||
184 | return (long)sin_table[val]; | ||
185 | else/* phase 91-180 degree */ | ||
186 | return (long)sin_table[180-val]; | ||
187 | } | ||
188 | else | ||
189 | { | ||
190 | if (val < 271)/* phase 181-270 degree */ | ||
191 | return -(long)sin_table[val-180]; | ||
192 | else/* phase 270-359 degree */ | ||
193 | return -(long)sin_table[360-val]; | ||
194 | } | ||
195 | return 0; | ||
196 | } | ||
197 | |||
198 | /** | ||
199 | * Fixed point cosinus using a lookup table | ||
200 | * don't forget to divide the result by 16384 to get the actual cosinus value | ||
201 | * @param val sinus argument in degree | ||
202 | * @return cos(val)*16384 | ||
203 | */ | ||
204 | long cos_int(int val) | ||
205 | { | ||
206 | val = (val+360)%360; | ||
207 | if (val < 181) | ||
208 | { | ||
209 | if (val < 91)/* phase 0-90 degree */ | ||
210 | return (long)sin_table[90-val]; | ||
211 | else/* phase 91-180 degree */ | ||
212 | return -(long)sin_table[val-90]; | ||
213 | } | ||
214 | else | ||
215 | { | ||
216 | if (val < 271)/* phase 181-270 degree */ | ||
217 | return -(long)sin_table[270-val]; | ||
218 | else/* phase 270-359 degree */ | ||
219 | return (long)sin_table[val-270]; | ||
220 | } | ||
221 | return 0; | ||
222 | } | ||
223 | |||
224 | /** | ||
225 | * Fixed-point natural log | ||
226 | * taken from http://www.quinapalus.com/efunc.html | ||
227 | * "The code assumes integers are at least 32 bits long. The (positive) | ||
228 | * argument and the result of the function are both expressed as fixed-point | ||
229 | * values with 16 fractional bits, although intermediates are kept with 28 | ||
230 | * bits of precision to avoid loss of accuracy during shifts." | ||
231 | */ | ||
232 | |||
233 | long flog(int x) { | ||
234 | long t,y; | ||
235 | |||
236 | y=0xa65af; | ||
237 | if(x<0x00008000) x<<=16, y-=0xb1721; | ||
238 | if(x<0x00800000) x<<= 8, y-=0x58b91; | ||
239 | if(x<0x08000000) x<<= 4, y-=0x2c5c8; | ||
240 | if(x<0x20000000) x<<= 2, y-=0x162e4; | ||
241 | if(x<0x40000000) x<<= 1, y-=0x0b172; | ||
242 | t=x+(x>>1); if((t&0x80000000)==0) x=t,y-=0x067cd; | ||
243 | t=x+(x>>2); if((t&0x80000000)==0) x=t,y-=0x03920; | ||
244 | t=x+(x>>3); if((t&0x80000000)==0) x=t,y-=0x01e27; | ||
245 | t=x+(x>>4); if((t&0x80000000)==0) x=t,y-=0x00f85; | ||
246 | t=x+(x>>5); if((t&0x80000000)==0) x=t,y-=0x007e1; | ||
247 | t=x+(x>>6); if((t&0x80000000)==0) x=t,y-=0x003f8; | ||
248 | t=x+(x>>7); if((t&0x80000000)==0) x=t,y-=0x001fe; | ||
249 | x=0x80000000-x; | ||
250 | y-=x>>15; | ||
251 | return y; | ||
252 | } | ||
253 | |||
254 | /** MODIFIED FROM replaygain.c */ | ||
255 | /* These math routines have 64-bit internal precision to avoid overflows. | ||
256 | * Arguments and return values are 32-bit (long) precision. | ||
257 | */ | ||
258 | |||
259 | #define FP_MUL64(x, y) (((x) * (y)) >> (fracbits)) | ||
260 | #define FP_DIV64(x, y) (((x) << (fracbits)) / (y)) | ||
261 | |||
262 | static long long fp_exp10(long long x, unsigned int fracbits); | ||
263 | static long long fp_log10(long long n, unsigned int fracbits); | ||
264 | |||
265 | /* constants in fixed point format, 28 fractional bits */ | ||
266 | #define FP28_LN2 (186065279LL) /* ln(2) */ | ||
267 | #define FP28_LN2_INV (387270501LL) /* 1/ln(2) */ | ||
268 | #define FP28_EXP_ZERO (44739243LL) /* 1/6 */ | ||
269 | #define FP28_EXP_ONE (-745654LL) /* -1/360 */ | ||
270 | #define FP28_EXP_TWO (12428LL) /* 1/21600 */ | ||
271 | #define FP28_LN10 (618095479LL) /* ln(10) */ | ||
272 | #define FP28_LOG10OF2 (80807124LL) /* log10(2) */ | ||
273 | |||
274 | #define TOL_BITS 2 /* log calculation tolerance */ | ||
275 | |||
276 | |||
277 | /* The fpexp10 fixed point math routine is based | ||
278 | * on oMathFP by Dan Carter (http://orbisstudios.com). | ||
279 | */ | ||
280 | |||
281 | /** FIXED POINT EXP10 | ||
282 | * Return 10^x as FP integer. Argument is FP integer. | ||
283 | */ | ||
284 | static long long fp_exp10(long long x, unsigned int fracbits) | ||
285 | { | ||
286 | long long k; | ||
287 | long long z; | ||
288 | long long R; | ||
289 | long long xp; | ||
290 | |||
291 | /* scale constants */ | ||
292 | const long long fp_one = (1 << fracbits); | ||
293 | const long long fp_half = (1 << (fracbits - 1)); | ||
294 | const long long fp_two = (2 << fracbits); | ||
295 | const long long fp_mask = (fp_one - 1); | ||
296 | const long long fp_ln2_inv = (FP28_LN2_INV >> (28 - fracbits)); | ||
297 | const long long fp_ln2 = (FP28_LN2 >> (28 - fracbits)); | ||
298 | const long long fp_ln10 = (FP28_LN10 >> (28 - fracbits)); | ||
299 | const long long fp_exp_zero = (FP28_EXP_ZERO >> (28 - fracbits)); | ||
300 | const long long fp_exp_one = (FP28_EXP_ONE >> (28 - fracbits)); | ||
301 | const long long fp_exp_two = (FP28_EXP_TWO >> (28 - fracbits)); | ||
302 | |||
303 | /* exp(0) = 1 */ | ||
304 | if (x == 0) | ||
305 | { | ||
306 | return fp_one; | ||
307 | } | ||
308 | |||
309 | /* convert from base 10 to base e */ | ||
310 | x = FP_MUL64(x, fp_ln10); | ||
311 | |||
312 | /* calculate exp(x) */ | ||
313 | k = (FP_MUL64(abs(x), fp_ln2_inv) + fp_half) & ~fp_mask; | ||
314 | |||
315 | if (x < 0) | ||
316 | { | ||
317 | k = -k; | ||
318 | } | ||
319 | |||
320 | x -= FP_MUL64(k, fp_ln2); | ||
321 | z = FP_MUL64(x, x); | ||
322 | R = fp_two + FP_MUL64(z, fp_exp_zero + FP_MUL64(z, fp_exp_one | ||
323 | + FP_MUL64(z, fp_exp_two))); | ||
324 | xp = fp_one + FP_DIV64(FP_MUL64(fp_two, x), R - x); | ||
325 | |||
326 | if (k < 0) | ||
327 | { | ||
328 | k = fp_one >> (-k >> fracbits); | ||
329 | } | ||
330 | else | ||
331 | { | ||
332 | k = fp_one << (k >> fracbits); | ||
333 | } | ||
334 | |||
335 | return FP_MUL64(k, xp); | ||
336 | } | ||
337 | |||
338 | |||
339 | /** FIXED POINT LOG10 | ||
340 | * Return log10(x) as FP integer. Argument is FP integer. | ||
341 | */ | ||
342 | static long long fp_log10(long long n, unsigned int fracbits) | ||
343 | { | ||
344 | /* Calculate log2 of argument */ | ||
345 | |||
346 | long long log2, frac; | ||
347 | const long long fp_one = (1 << fracbits); | ||
348 | const long long fp_two = (2 << fracbits); | ||
349 | const long tolerance = (1 << ((fracbits / 2) + 2)); | ||
350 | |||
351 | if (n <=0) return FP_NEGINF; | ||
352 | log2 = 0; | ||
353 | |||
354 | /* integer part */ | ||
355 | while (n < fp_one) | ||
356 | { | ||
357 | log2 -= fp_one; | ||
358 | n <<= 1; | ||
359 | } | ||
360 | while (n >= fp_two) | ||
361 | { | ||
362 | log2 += fp_one; | ||
363 | n >>= 1; | ||
364 | } | ||
365 | |||
366 | /* fractional part */ | ||
367 | frac = fp_one; | ||
368 | while (frac > tolerance) | ||
369 | { | ||
370 | frac >>= 1; | ||
371 | n = FP_MUL64(n, n); | ||
372 | if (n >= fp_two) | ||
373 | { | ||
374 | n >>= 1; | ||
375 | log2 += frac; | ||
376 | } | ||
377 | } | ||
378 | |||
379 | /* convert log2 to log10 */ | ||
380 | return FP_MUL64(log2, (FP28_LOG10OF2 >> (28 - fracbits))); | ||
381 | } | ||
382 | |||
383 | |||
384 | /** CONVERT FACTOR TO DECIBELS */ | ||
385 | long fp_decibels(unsigned long factor, unsigned int fracbits) | ||
386 | { | ||
387 | long long decibels; | ||
388 | long long f = (long long)factor; | ||
389 | bool neg; | ||
390 | |||
391 | /* keep factor in signed long range */ | ||
392 | if (f >= (1LL << 31)) | ||
393 | f = (1LL << 31) - 1; | ||
394 | |||
395 | /* decibels = 20 * log10(factor) */ | ||
396 | decibels = FP_MUL64((20LL << fracbits), fp_log10(f, fracbits)); | ||
397 | |||
398 | /* keep result in signed long range */ | ||
399 | if ((neg = (decibels < 0))) | ||
400 | decibels = -decibels; | ||
401 | if (decibels >= (1LL << 31)) | ||
402 | return neg ? FP_NEGINF : FP_INF; | ||
403 | |||
404 | return neg ? (long)-decibels : (long)decibels; | ||
405 | } | ||
406 | |||
407 | |||
408 | /** CONVERT DECIBELS TO FACTOR */ | ||
409 | long fp_factor(long decibels, unsigned int fracbits) | ||
410 | { | ||
411 | bool neg; | ||
412 | long long factor; | ||
413 | long long db = (long long)decibels; | ||
414 | |||
415 | /* if decibels is 0, factor is 1 */ | ||
416 | if (db == 0) | ||
417 | return (1L << fracbits); | ||
418 | |||
419 | /* calculate for positive decibels only */ | ||
420 | if ((neg = (db < 0))) | ||
421 | db = -db; | ||
422 | |||
423 | /* factor = 10 ^ (decibels / 20) */ | ||
424 | factor = fp_exp10(FP_DIV64(db, (20LL << fracbits)), fracbits); | ||
425 | |||
426 | /* keep result in signed long range, return 0 if very small */ | ||
427 | if (factor >= (1LL << 31)) | ||
428 | { | ||
429 | if (neg) | ||
430 | return 0; | ||
431 | else | ||
432 | return FP_INF; | ||
433 | } | ||
434 | |||
435 | /* if negative argument, factor is 1 / result */ | ||
436 | if (neg) | ||
437 | factor = FP_DIV64((1LL << fracbits), factor); | ||
438 | |||
439 | return (long)factor; | ||
440 | } | ||