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author | Michael Sevakis <jethead71@rockbox.org> | 2013-04-16 17:47:58 -0400 |
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committer | Michael Sevakis <jethead71@rockbox.org> | 2013-04-26 00:11:04 +0200 |
commit | 95e23defb085ee1a846ec2d379368485921d5aee (patch) | |
tree | 0bdb31f562fef8c7ff5f3f7dba9c54f9c1e84a76 /apps/fixedpoint.c | |
parent | 8829e909b4e756bfb2ad9210eec61d0dc55e1731 (diff) | |
download | rockbox-95e23defb085ee1a846ec2d379368485921d5aee.tar.gz rockbox-95e23defb085ee1a846ec2d379368485921d5aee.zip |
Make fixepoint.c as a shared library (libfixedpoint.a).
Change-Id: Icc10d6e85f890c432f191233a4d64e09f00be43d
Reviewed-on: http://gerrit.rockbox.org/456
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Tested-by: Michael Sevakis <jethead71@rockbox.org>
Diffstat (limited to 'apps/fixedpoint.c')
-rw-r--r-- | apps/fixedpoint.c | 472 |
1 files changed, 0 insertions, 472 deletions
diff --git a/apps/fixedpoint.c b/apps/fixedpoint.c deleted file mode 100644 index b212929245..0000000000 --- a/apps/fixedpoint.c +++ /dev/null | |||
@@ -1,472 +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 | #include <inttypes.h> | ||
28 | |||
29 | #ifndef BIT_N | ||
30 | #define BIT_N(n) (1U << (n)) | ||
31 | #endif | ||
32 | |||
33 | /** TAKEN FROM ORIGINAL fixedpoint.h */ | ||
34 | /* Inverse gain of circular cordic rotation in s0.31 format. */ | ||
35 | static const long cordic_circular_gain = 0xb2458939; /* 0.607252929 */ | ||
36 | |||
37 | /* Table of values of atan(2^-i) in 0.32 format fractions of pi where pi = 0xffffffff / 2 */ | ||
38 | static const unsigned long atan_table[] = { | ||
39 | 0x1fffffff, /* +0.785398163 (or pi/4) */ | ||
40 | 0x12e4051d, /* +0.463647609 */ | ||
41 | 0x09fb385b, /* +0.244978663 */ | ||
42 | 0x051111d4, /* +0.124354995 */ | ||
43 | 0x028b0d43, /* +0.062418810 */ | ||
44 | 0x0145d7e1, /* +0.031239833 */ | ||
45 | 0x00a2f61e, /* +0.015623729 */ | ||
46 | 0x00517c55, /* +0.007812341 */ | ||
47 | 0x0028be53, /* +0.003906230 */ | ||
48 | 0x00145f2e, /* +0.001953123 */ | ||
49 | 0x000a2f98, /* +0.000976562 */ | ||
50 | 0x000517cc, /* +0.000488281 */ | ||
51 | 0x00028be6, /* +0.000244141 */ | ||
52 | 0x000145f3, /* +0.000122070 */ | ||
53 | 0x0000a2f9, /* +0.000061035 */ | ||
54 | 0x0000517c, /* +0.000030518 */ | ||
55 | 0x000028be, /* +0.000015259 */ | ||
56 | 0x0000145f, /* +0.000007629 */ | ||
57 | 0x00000a2f, /* +0.000003815 */ | ||
58 | 0x00000517, /* +0.000001907 */ | ||
59 | 0x0000028b, /* +0.000000954 */ | ||
60 | 0x00000145, /* +0.000000477 */ | ||
61 | 0x000000a2, /* +0.000000238 */ | ||
62 | 0x00000051, /* +0.000000119 */ | ||
63 | 0x00000028, /* +0.000000060 */ | ||
64 | 0x00000014, /* +0.000000030 */ | ||
65 | 0x0000000a, /* +0.000000015 */ | ||
66 | 0x00000005, /* +0.000000007 */ | ||
67 | 0x00000002, /* +0.000000004 */ | ||
68 | 0x00000001, /* +0.000000002 */ | ||
69 | 0x00000000, /* +0.000000001 */ | ||
70 | 0x00000000, /* +0.000000000 */ | ||
71 | }; | ||
72 | |||
73 | /* Precalculated sine and cosine * 16384 (2^14) (fixed point 18.14) */ | ||
74 | static const short sin_table[91] = | ||
75 | { | ||
76 | 0, 285, 571, 857, 1142, 1427, 1712, 1996, 2280, 2563, | ||
77 | 2845, 3126, 3406, 3685, 3963, 4240, 4516, 4790, 5062, 5334, | ||
78 | 5603, 5871, 6137, 6401, 6663, 6924, 7182, 7438, 7691, 7943, | ||
79 | 8191, 8438, 8682, 8923, 9161, 9397, 9630, 9860, 10086, 10310, | ||
80 | 10531, 10748, 10963, 11173, 11381, 11585, 11785, 11982, 12175, 12365, | ||
81 | 12550, 12732, 12910, 13084, 13254, 13420, 13582, 13740, 13894, 14043, | ||
82 | 14188, 14329, 14466, 14598, 14725, 14848, 14967, 15081, 15190, 15295, | ||
83 | 15395, 15491, 15582, 15668, 15749, 15825, 15897, 15964, 16025, 16082, | ||
84 | 16135, 16182, 16224, 16261, 16294, 16321, 16344, 16361, 16374, 16381, | ||
85 | 16384 | ||
86 | }; | ||
87 | |||
88 | /** | ||
89 | * Implements sin and cos using CORDIC rotation. | ||
90 | * | ||
91 | * @param phase has range from 0 to 0xffffffff, representing 0 and | ||
92 | * 2*pi respectively. | ||
93 | * @param cos return address for cos | ||
94 | * @return sin of phase, value is a signed value from LONG_MIN to LONG_MAX, | ||
95 | * representing -1 and 1 respectively. | ||
96 | */ | ||
97 | long fp_sincos(unsigned long phase, long *cos) | ||
98 | { | ||
99 | int32_t x, x1, y, y1; | ||
100 | unsigned long z, z1; | ||
101 | int i; | ||
102 | |||
103 | /* Setup initial vector */ | ||
104 | x = cordic_circular_gain; | ||
105 | y = 0; | ||
106 | z = phase; | ||
107 | |||
108 | /* The phase has to be somewhere between 0..pi for this to work right */ | ||
109 | if (z < 0xffffffff / 4) { | ||
110 | /* z in first quadrant, z += pi/2 to correct */ | ||
111 | x = -x; | ||
112 | z += 0xffffffff / 4; | ||
113 | } else if (z < 3 * (0xffffffff / 4)) { | ||
114 | /* z in third quadrant, z -= pi/2 to correct */ | ||
115 | z -= 0xffffffff / 4; | ||
116 | } else { | ||
117 | /* z in fourth quadrant, z -= 3pi/2 to correct */ | ||
118 | x = -x; | ||
119 | z -= 3 * (0xffffffff / 4); | ||
120 | } | ||
121 | |||
122 | /* Each iteration adds roughly 1-bit of extra precision */ | ||
123 | for (i = 0; i < 31; i++) { | ||
124 | x1 = x >> i; | ||
125 | y1 = y >> i; | ||
126 | z1 = atan_table[i]; | ||
127 | |||
128 | /* Decided which direction to rotate vector. Pivot point is pi/2 */ | ||
129 | if (z >= 0xffffffff / 4) { | ||
130 | x -= y1; | ||
131 | y += x1; | ||
132 | z -= z1; | ||
133 | } else { | ||
134 | x += y1; | ||
135 | y -= x1; | ||
136 | z += z1; | ||
137 | } | ||
138 | } | ||
139 | |||
140 | if (cos) | ||
141 | *cos = x; | ||
142 | |||
143 | return y; | ||
144 | } | ||
145 | |||
146 | |||
147 | #if defined(PLUGIN) || defined(CODEC) | ||
148 | /** | ||
149 | * Fixed point square root via Newton-Raphson. | ||
150 | * @param x square root argument. | ||
151 | * @param fracbits specifies number of fractional bits in argument. | ||
152 | * @return Square root of argument in same fixed point format as input. | ||
153 | * | ||
154 | * This routine has been modified to run longer for greater precision, | ||
155 | * but cuts calculation short if the answer is reached sooner. | ||
156 | */ | ||
157 | long fp_sqrt(long x, unsigned int fracbits) | ||
158 | { | ||
159 | unsigned long xfp, b; | ||
160 | int n = 8; /* iteration limit (should terminate earlier) */ | ||
161 | |||
162 | if (x <= 0) | ||
163 | return 0; /* no sqrt(neg), or just sqrt(0) = 0 */ | ||
164 | |||
165 | /* Increase working precision by one bit */ | ||
166 | xfp = x << 1; | ||
167 | fracbits++; | ||
168 | |||
169 | /* Get the midpoint between fracbits index and the highest bit index */ | ||
170 | b = ((sizeof(xfp)*8-1) - __builtin_clzl(xfp) + fracbits) >> 1; | ||
171 | b = BIT_N(b); | ||
172 | |||
173 | do | ||
174 | { | ||
175 | unsigned long c = b; | ||
176 | b = (fp_div(xfp, b, fracbits) + b) >> 1; | ||
177 | if (c == b) break; | ||
178 | } | ||
179 | while (n-- > 0); | ||
180 | |||
181 | return b >> 1; | ||
182 | } | ||
183 | |||
184 | /* Accurate int sqrt with only elementary operations. | ||
185 | * Snagged from: | ||
186 | * http://www.devmaster.net/articles/fixed-point-optimizations/ */ | ||
187 | unsigned long isqrt(unsigned long x) | ||
188 | { | ||
189 | /* Adding CLZ could optimize this further */ | ||
190 | unsigned long g = 0; | ||
191 | int bshift = 15; | ||
192 | unsigned long b = 1ul << bshift; | ||
193 | |||
194 | do | ||
195 | { | ||
196 | unsigned long temp = (g + g + b) << bshift; | ||
197 | |||
198 | if (x > temp) | ||
199 | { | ||
200 | g += b; | ||
201 | x -= temp; | ||
202 | } | ||
203 | |||
204 | b >>= 1; | ||
205 | } | ||
206 | while (bshift--); | ||
207 | |||
208 | return g; | ||
209 | } | ||
210 | #endif /* PLUGIN or CODEC */ | ||
211 | |||
212 | |||
213 | #if defined(PLUGIN) | ||
214 | /** | ||
215 | * Fixed point sinus using a lookup table | ||
216 | * don't forget to divide the result by 16384 to get the actual sinus value | ||
217 | * @param val sinus argument in degree | ||
218 | * @return sin(val)*16384 | ||
219 | */ | ||
220 | long fp14_sin(int val) | ||
221 | { | ||
222 | val = (val+360)%360; | ||
223 | if (val < 181) | ||
224 | { | ||
225 | if (val < 91)/* phase 0-90 degree */ | ||
226 | return (long)sin_table[val]; | ||
227 | else/* phase 91-180 degree */ | ||
228 | return (long)sin_table[180-val]; | ||
229 | } | ||
230 | else | ||
231 | { | ||
232 | if (val < 271)/* phase 181-270 degree */ | ||
233 | return -(long)sin_table[val-180]; | ||
234 | else/* phase 270-359 degree */ | ||
235 | return -(long)sin_table[360-val]; | ||
236 | } | ||
237 | return 0; | ||
238 | } | ||
239 | |||
240 | /** | ||
241 | * Fixed point cosinus using a lookup table | ||
242 | * don't forget to divide the result by 16384 to get the actual cosinus value | ||
243 | * @param val sinus argument in degree | ||
244 | * @return cos(val)*16384 | ||
245 | */ | ||
246 | long fp14_cos(int val) | ||
247 | { | ||
248 | val = (val+360)%360; | ||
249 | if (val < 181) | ||
250 | { | ||
251 | if (val < 91)/* phase 0-90 degree */ | ||
252 | return (long)sin_table[90-val]; | ||
253 | else/* phase 91-180 degree */ | ||
254 | return -(long)sin_table[val-90]; | ||
255 | } | ||
256 | else | ||
257 | { | ||
258 | if (val < 271)/* phase 181-270 degree */ | ||
259 | return -(long)sin_table[270-val]; | ||
260 | else/* phase 270-359 degree */ | ||
261 | return (long)sin_table[val-270]; | ||
262 | } | ||
263 | return 0; | ||
264 | } | ||
265 | |||
266 | /** | ||
267 | * Fixed-point natural log | ||
268 | * taken from http://www.quinapalus.com/efunc.html | ||
269 | * "The code assumes integers are at least 32 bits long. The (positive) | ||
270 | * argument and the result of the function are both expressed as fixed-point | ||
271 | * values with 16 fractional bits, although intermediates are kept with 28 | ||
272 | * bits of precision to avoid loss of accuracy during shifts." | ||
273 | */ | ||
274 | long fp16_log(int x) | ||
275 | { | ||
276 | int t; | ||
277 | int y = 0xa65af; | ||
278 | |||
279 | if (x < 0x00008000) x <<=16, y -= 0xb1721; | ||
280 | if (x < 0x00800000) x <<= 8, y -= 0x58b91; | ||
281 | if (x < 0x08000000) x <<= 4, y -= 0x2c5c8; | ||
282 | if (x < 0x20000000) x <<= 2, y -= 0x162e4; | ||
283 | if (x < 0x40000000) x <<= 1, y -= 0x0b172; | ||
284 | t = x + (x >> 1); if ((t & 0x80000000) == 0) x = t, y -= 0x067cd; | ||
285 | t = x + (x >> 2); if ((t & 0x80000000) == 0) x = t, y -= 0x03920; | ||
286 | t = x + (x >> 3); if ((t & 0x80000000) == 0) x = t, y -= 0x01e27; | ||
287 | t = x + (x >> 4); if ((t & 0x80000000) == 0) x = t, y -= 0x00f85; | ||
288 | t = x + (x >> 5); if ((t & 0x80000000) == 0) x = t, y -= 0x007e1; | ||
289 | t = x + (x >> 6); if ((t & 0x80000000) == 0) x = t, y -= 0x003f8; | ||
290 | t = x + (x >> 7); if ((t & 0x80000000) == 0) x = t, y -= 0x001fe; | ||
291 | x = 0x80000000 - x; | ||
292 | y -= x >> 15; | ||
293 | |||
294 | return y; | ||
295 | } | ||
296 | |||
297 | /** | ||
298 | * Fixed-point exponential | ||
299 | * taken from http://www.quinapalus.com/efunc.html | ||
300 | * "The code assumes integers are at least 32 bits long. The (non-negative) | ||
301 | * argument and the result of the function are both expressed as fixed-point | ||
302 | * values with 16 fractional bits. Notice that after 11 steps of the | ||
303 | * algorithm the constants involved become such that the code is simply | ||
304 | * doing a multiplication: this is explained in the note below. | ||
305 | * The extension to negative arguments is left as an exercise." | ||
306 | */ | ||
307 | long fp16_exp(int x) | ||
308 | { | ||
309 | int t; | ||
310 | int y = 0x00010000; | ||
311 | |||
312 | if (x < 0) x += 0xb1721, y >>= 16; | ||
313 | t = x - 0x58b91; if (t >= 0) x = t, y <<= 8; | ||
314 | t = x - 0x2c5c8; if (t >= 0) x = t, y <<= 4; | ||
315 | t = x - 0x162e4; if (t >= 0) x = t, y <<= 2; | ||
316 | t = x - 0x0b172; if (t >= 0) x = t, y <<= 1; | ||
317 | t = x - 0x067cd; if (t >= 0) x = t, y += y >> 1; | ||
318 | t = x - 0x03920; if (t >= 0) x = t, y += y >> 2; | ||
319 | t = x - 0x01e27; if (t >= 0) x = t, y += y >> 3; | ||
320 | t = x - 0x00f85; if (t >= 0) x = t, y += y >> 4; | ||
321 | t = x - 0x007e1; if (t >= 0) x = t, y += y >> 5; | ||
322 | t = x - 0x003f8; if (t >= 0) x = t, y += y >> 6; | ||
323 | t = x - 0x001fe; if (t >= 0) x = t, y += y >> 7; | ||
324 | y += ((y >> 8) * x) >> 8; | ||
325 | |||
326 | return y; | ||
327 | } | ||
328 | #endif /* PLUGIN */ | ||
329 | |||
330 | |||
331 | #if (!defined(PLUGIN) && !defined(CODEC)) | ||
332 | /** MODIFIED FROM replaygain.c */ | ||
333 | |||
334 | #define FP_MUL_FRAC(x, y) fp_mul(x, y, fracbits) | ||
335 | #define FP_DIV_FRAC(x, y) fp_div(x, y, fracbits) | ||
336 | |||
337 | /* constants in fixed point format, 28 fractional bits */ | ||
338 | #define FP28_LN2 (186065279L) /* ln(2) */ | ||
339 | #define FP28_LN2_INV (387270501L) /* 1/ln(2) */ | ||
340 | #define FP28_EXP_ZERO (44739243L) /* 1/6 */ | ||
341 | #define FP28_EXP_ONE (-745654L) /* -1/360 */ | ||
342 | #define FP28_EXP_TWO (12428L) /* 1/21600 */ | ||
343 | #define FP28_LN10 (618095479L) /* ln(10) */ | ||
344 | #define FP28_LOG10OF2 (80807124L) /* log10(2) */ | ||
345 | |||
346 | #define TOL_BITS 2 /* log calculation tolerance */ | ||
347 | |||
348 | |||
349 | /* The fpexp10 fixed point math routine is based | ||
350 | * on oMathFP by Dan Carter (http://orbisstudios.com). | ||
351 | */ | ||
352 | |||
353 | /** FIXED POINT EXP10 | ||
354 | * Return 10^x as FP integer. Argument is FP integer. | ||
355 | */ | ||
356 | long fp_exp10(long x, unsigned int fracbits) | ||
357 | { | ||
358 | long k; | ||
359 | long z; | ||
360 | long R; | ||
361 | long xp; | ||
362 | |||
363 | /* scale constants */ | ||
364 | const long fp_one = (1 << fracbits); | ||
365 | const long fp_half = (1 << (fracbits - 1)); | ||
366 | const long fp_two = (2 << fracbits); | ||
367 | const long fp_mask = (fp_one - 1); | ||
368 | const long fp_ln2_inv = (FP28_LN2_INV >> (28 - fracbits)); | ||
369 | const long fp_ln2 = (FP28_LN2 >> (28 - fracbits)); | ||
370 | const long fp_ln10 = (FP28_LN10 >> (28 - fracbits)); | ||
371 | const long fp_exp_zero = (FP28_EXP_ZERO >> (28 - fracbits)); | ||
372 | const long fp_exp_one = (FP28_EXP_ONE >> (28 - fracbits)); | ||
373 | const long fp_exp_two = (FP28_EXP_TWO >> (28 - fracbits)); | ||
374 | |||
375 | /* exp(0) = 1 */ | ||
376 | if (x == 0) | ||
377 | { | ||
378 | return fp_one; | ||
379 | } | ||
380 | |||
381 | /* convert from base 10 to base e */ | ||
382 | x = FP_MUL_FRAC(x, fp_ln10); | ||
383 | |||
384 | /* calculate exp(x) */ | ||
385 | k = (FP_MUL_FRAC(abs(x), fp_ln2_inv) + fp_half) & ~fp_mask; | ||
386 | |||
387 | if (x < 0) | ||
388 | { | ||
389 | k = -k; | ||
390 | } | ||
391 | |||
392 | x -= FP_MUL_FRAC(k, fp_ln2); | ||
393 | z = FP_MUL_FRAC(x, x); | ||
394 | R = fp_two + FP_MUL_FRAC(z, fp_exp_zero + FP_MUL_FRAC(z, fp_exp_one | ||
395 | + FP_MUL_FRAC(z, fp_exp_two))); | ||
396 | xp = fp_one + FP_DIV_FRAC(FP_MUL_FRAC(fp_two, x), R - x); | ||
397 | |||
398 | if (k < 0) | ||
399 | { | ||
400 | k = fp_one >> (-k >> fracbits); | ||
401 | } | ||
402 | else | ||
403 | { | ||
404 | k = fp_one << (k >> fracbits); | ||
405 | } | ||
406 | |||
407 | return FP_MUL_FRAC(k, xp); | ||
408 | } | ||
409 | |||
410 | |||
411 | #if 0 /* useful code, but not currently used */ | ||
412 | /** FIXED POINT LOG10 | ||
413 | * Return log10(x) as FP integer. Argument is FP integer. | ||
414 | */ | ||
415 | static long fp_log10(long n, unsigned int fracbits) | ||
416 | { | ||
417 | /* Calculate log2 of argument */ | ||
418 | |||
419 | long log2, frac; | ||
420 | const long fp_one = (1 << fracbits); | ||
421 | const long fp_two = (2 << fracbits); | ||
422 | const long tolerance = (1 << ((fracbits / 2) + 2)); | ||
423 | |||
424 | if (n <=0) return FP_NEGINF; | ||
425 | log2 = 0; | ||
426 | |||
427 | /* integer part */ | ||
428 | while (n < fp_one) | ||
429 | { | ||
430 | log2 -= fp_one; | ||
431 | n <<= 1; | ||
432 | } | ||
433 | while (n >= fp_two) | ||
434 | { | ||
435 | log2 += fp_one; | ||
436 | n >>= 1; | ||
437 | } | ||
438 | |||
439 | /* fractional part */ | ||
440 | frac = fp_one; | ||
441 | while (frac > tolerance) | ||
442 | { | ||
443 | frac >>= 1; | ||
444 | n = FP_MUL_FRAC(n, n); | ||
445 | if (n >= fp_two) | ||
446 | { | ||
447 | n >>= 1; | ||
448 | log2 += frac; | ||
449 | } | ||
450 | } | ||
451 | |||
452 | /* convert log2 to log10 */ | ||
453 | return FP_MUL_FRAC(log2, (FP28_LOG10OF2 >> (28 - fracbits))); | ||
454 | } | ||
455 | |||
456 | |||
457 | /** CONVERT FACTOR TO DECIBELS */ | ||
458 | long fp_decibels(unsigned long factor, unsigned int fracbits) | ||
459 | { | ||
460 | /* decibels = 20 * log10(factor) */ | ||
461 | return FP_MUL_FRAC((20L << fracbits), fp_log10(factor, fracbits)); | ||
462 | } | ||
463 | #endif /* unused code */ | ||
464 | |||
465 | |||
466 | /** CONVERT DECIBELS TO FACTOR */ | ||
467 | long fp_factor(long decibels, unsigned int fracbits) | ||
468 | { | ||
469 | /* factor = 10 ^ (decibels / 20) */ | ||
470 | return fp_exp10(FP_DIV_FRAC(decibels, (20L << fracbits)), fracbits); | ||
471 | } | ||
472 | #endif /* !PLUGIN and !CODEC */ | ||