libFLAC/cpu.c: Get rid of OS_IS_ANDROID function
[flac.git] / src / libFLAC / float.c
1 /* libFLAC - Free Lossless Audio Codec library
2  * Copyright (C) 2004-2009  Josh Coalson
3  * Copyright (C) 2011-2014  Xiph.Org Foundation
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *
9  * - Redistributions of source code must retain the above copyright
10  * notice, this list of conditions and the following disclaimer.
11  *
12  * - Redistributions in binary form must reproduce the above copyright
13  * notice, this list of conditions and the following disclaimer in the
14  * documentation and/or other materials provided with the distribution.
15  *
16  * - Neither the name of the Xiph.org Foundation nor the names of its
17  * contributors may be used to endorse or promote products derived from
18  * this software without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
24  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
26  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
27  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
28  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
29  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
30  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32
33 #ifdef HAVE_CONFIG_H
34 #  include <config.h>
35 #endif
36
37 #include "FLAC/assert.h"
38 #include "share/compat.h"
39 #include "private/float.h"
40
41 #ifdef FLAC__INTEGER_ONLY_LIBRARY
42
43 const FLAC__fixedpoint FLAC__FP_ZERO = 0;
44 const FLAC__fixedpoint FLAC__FP_ONE_HALF = 0x00008000;
45 const FLAC__fixedpoint FLAC__FP_ONE = 0x00010000;
46 const FLAC__fixedpoint FLAC__FP_LN2 = 45426;
47 const FLAC__fixedpoint FLAC__FP_E = 178145;
48
49 /* Lookup tables for Knuth's logarithm algorithm */
50 #define LOG2_LOOKUP_PRECISION 16
51 static const FLAC__uint32 log2_lookup[][LOG2_LOOKUP_PRECISION] = {
52         {
53                 /*
54                  * 0 fraction bits
55                  */
56                 /* undefined */ 0x00000000,
57                 /* lg(2/1) = */ 0x00000001,
58                 /* lg(4/3) = */ 0x00000000,
59                 /* lg(8/7) = */ 0x00000000,
60                 /* lg(16/15) = */ 0x00000000,
61                 /* lg(32/31) = */ 0x00000000,
62                 /* lg(64/63) = */ 0x00000000,
63                 /* lg(128/127) = */ 0x00000000,
64                 /* lg(256/255) = */ 0x00000000,
65                 /* lg(512/511) = */ 0x00000000,
66                 /* lg(1024/1023) = */ 0x00000000,
67                 /* lg(2048/2047) = */ 0x00000000,
68                 /* lg(4096/4095) = */ 0x00000000,
69                 /* lg(8192/8191) = */ 0x00000000,
70                 /* lg(16384/16383) = */ 0x00000000,
71                 /* lg(32768/32767) = */ 0x00000000
72         },
73         {
74                 /*
75                  * 4 fraction bits
76                  */
77                 /* undefined */ 0x00000000,
78                 /* lg(2/1) = */ 0x00000010,
79                 /* lg(4/3) = */ 0x00000007,
80                 /* lg(8/7) = */ 0x00000003,
81                 /* lg(16/15) = */ 0x00000001,
82                 /* lg(32/31) = */ 0x00000001,
83                 /* lg(64/63) = */ 0x00000000,
84                 /* lg(128/127) = */ 0x00000000,
85                 /* lg(256/255) = */ 0x00000000,
86                 /* lg(512/511) = */ 0x00000000,
87                 /* lg(1024/1023) = */ 0x00000000,
88                 /* lg(2048/2047) = */ 0x00000000,
89                 /* lg(4096/4095) = */ 0x00000000,
90                 /* lg(8192/8191) = */ 0x00000000,
91                 /* lg(16384/16383) = */ 0x00000000,
92                 /* lg(32768/32767) = */ 0x00000000
93         },
94         {
95                 /*
96                  * 8 fraction bits
97                  */
98                 /* undefined */ 0x00000000,
99                 /* lg(2/1) = */ 0x00000100,
100                 /* lg(4/3) = */ 0x0000006a,
101                 /* lg(8/7) = */ 0x00000031,
102                 /* lg(16/15) = */ 0x00000018,
103                 /* lg(32/31) = */ 0x0000000c,
104                 /* lg(64/63) = */ 0x00000006,
105                 /* lg(128/127) = */ 0x00000003,
106                 /* lg(256/255) = */ 0x00000001,
107                 /* lg(512/511) = */ 0x00000001,
108                 /* lg(1024/1023) = */ 0x00000000,
109                 /* lg(2048/2047) = */ 0x00000000,
110                 /* lg(4096/4095) = */ 0x00000000,
111                 /* lg(8192/8191) = */ 0x00000000,
112                 /* lg(16384/16383) = */ 0x00000000,
113                 /* lg(32768/32767) = */ 0x00000000
114         },
115         {
116                 /*
117                  * 12 fraction bits
118                  */
119                 /* undefined */ 0x00000000,
120                 /* lg(2/1) = */ 0x00001000,
121                 /* lg(4/3) = */ 0x000006a4,
122                 /* lg(8/7) = */ 0x00000315,
123                 /* lg(16/15) = */ 0x0000017d,
124                 /* lg(32/31) = */ 0x000000bc,
125                 /* lg(64/63) = */ 0x0000005d,
126                 /* lg(128/127) = */ 0x0000002e,
127                 /* lg(256/255) = */ 0x00000017,
128                 /* lg(512/511) = */ 0x0000000c,
129                 /* lg(1024/1023) = */ 0x00000006,
130                 /* lg(2048/2047) = */ 0x00000003,
131                 /* lg(4096/4095) = */ 0x00000001,
132                 /* lg(8192/8191) = */ 0x00000001,
133                 /* lg(16384/16383) = */ 0x00000000,
134                 /* lg(32768/32767) = */ 0x00000000
135         },
136         {
137                 /*
138                  * 16 fraction bits
139                  */
140                 /* undefined */ 0x00000000,
141                 /* lg(2/1) = */ 0x00010000,
142                 /* lg(4/3) = */ 0x00006a40,
143                 /* lg(8/7) = */ 0x00003151,
144                 /* lg(16/15) = */ 0x000017d6,
145                 /* lg(32/31) = */ 0x00000bba,
146                 /* lg(64/63) = */ 0x000005d1,
147                 /* lg(128/127) = */ 0x000002e6,
148                 /* lg(256/255) = */ 0x00000172,
149                 /* lg(512/511) = */ 0x000000b9,
150                 /* lg(1024/1023) = */ 0x0000005c,
151                 /* lg(2048/2047) = */ 0x0000002e,
152                 /* lg(4096/4095) = */ 0x00000017,
153                 /* lg(8192/8191) = */ 0x0000000c,
154                 /* lg(16384/16383) = */ 0x00000006,
155                 /* lg(32768/32767) = */ 0x00000003
156         },
157         {
158                 /*
159                  * 20 fraction bits
160                  */
161                 /* undefined */ 0x00000000,
162                 /* lg(2/1) = */ 0x00100000,
163                 /* lg(4/3) = */ 0x0006a3fe,
164                 /* lg(8/7) = */ 0x00031513,
165                 /* lg(16/15) = */ 0x00017d60,
166                 /* lg(32/31) = */ 0x0000bb9d,
167                 /* lg(64/63) = */ 0x00005d10,
168                 /* lg(128/127) = */ 0x00002e59,
169                 /* lg(256/255) = */ 0x00001721,
170                 /* lg(512/511) = */ 0x00000b8e,
171                 /* lg(1024/1023) = */ 0x000005c6,
172                 /* lg(2048/2047) = */ 0x000002e3,
173                 /* lg(4096/4095) = */ 0x00000171,
174                 /* lg(8192/8191) = */ 0x000000b9,
175                 /* lg(16384/16383) = */ 0x0000005c,
176                 /* lg(32768/32767) = */ 0x0000002e
177         },
178         {
179                 /*
180                  * 24 fraction bits
181                  */
182                 /* undefined */ 0x00000000,
183                 /* lg(2/1) = */ 0x01000000,
184                 /* lg(4/3) = */ 0x006a3fe6,
185                 /* lg(8/7) = */ 0x00315130,
186                 /* lg(16/15) = */ 0x0017d605,
187                 /* lg(32/31) = */ 0x000bb9ca,
188                 /* lg(64/63) = */ 0x0005d0fc,
189                 /* lg(128/127) = */ 0x0002e58f,
190                 /* lg(256/255) = */ 0x0001720e,
191                 /* lg(512/511) = */ 0x0000b8d8,
192                 /* lg(1024/1023) = */ 0x00005c61,
193                 /* lg(2048/2047) = */ 0x00002e2d,
194                 /* lg(4096/4095) = */ 0x00001716,
195                 /* lg(8192/8191) = */ 0x00000b8b,
196                 /* lg(16384/16383) = */ 0x000005c5,
197                 /* lg(32768/32767) = */ 0x000002e3
198         },
199         {
200                 /*
201                  * 28 fraction bits
202                  */
203                 /* undefined */ 0x00000000,
204                 /* lg(2/1) = */ 0x10000000,
205                 /* lg(4/3) = */ 0x06a3fe5c,
206                 /* lg(8/7) = */ 0x03151301,
207                 /* lg(16/15) = */ 0x017d6049,
208                 /* lg(32/31) = */ 0x00bb9ca6,
209                 /* lg(64/63) = */ 0x005d0fba,
210                 /* lg(128/127) = */ 0x002e58f7,
211                 /* lg(256/255) = */ 0x001720da,
212                 /* lg(512/511) = */ 0x000b8d87,
213                 /* lg(1024/1023) = */ 0x0005c60b,
214                 /* lg(2048/2047) = */ 0x0002e2d7,
215                 /* lg(4096/4095) = */ 0x00017160,
216                 /* lg(8192/8191) = */ 0x0000b8ad,
217                 /* lg(16384/16383) = */ 0x00005c56,
218                 /* lg(32768/32767) = */ 0x00002e2b
219         }
220 };
221
222 #if 0
223 static const FLAC__uint64 log2_lookup_wide[] = {
224         {
225                 /*
226                  * 32 fraction bits
227                  */
228                 /* undefined */ 0x00000000,
229                 /* lg(2/1) = */ FLAC__U64L(0x100000000),
230                 /* lg(4/3) = */ FLAC__U64L(0x6a3fe5c6),
231                 /* lg(8/7) = */ FLAC__U64L(0x31513015),
232                 /* lg(16/15) = */ FLAC__U64L(0x17d60497),
233                 /* lg(32/31) = */ FLAC__U64L(0x0bb9ca65),
234                 /* lg(64/63) = */ FLAC__U64L(0x05d0fba2),
235                 /* lg(128/127) = */ FLAC__U64L(0x02e58f74),
236                 /* lg(256/255) = */ FLAC__U64L(0x01720d9c),
237                 /* lg(512/511) = */ FLAC__U64L(0x00b8d875),
238                 /* lg(1024/1023) = */ FLAC__U64L(0x005c60aa),
239                 /* lg(2048/2047) = */ FLAC__U64L(0x002e2d72),
240                 /* lg(4096/4095) = */ FLAC__U64L(0x00171600),
241                 /* lg(8192/8191) = */ FLAC__U64L(0x000b8ad2),
242                 /* lg(16384/16383) = */ FLAC__U64L(0x0005c55d),
243                 /* lg(32768/32767) = */ FLAC__U64L(0x0002e2ac)
244         },
245         {
246                 /*
247                  * 48 fraction bits
248                  */
249                 /* undefined */ 0x00000000,
250                 /* lg(2/1) = */ FLAC__U64L(0x1000000000000),
251                 /* lg(4/3) = */ FLAC__U64L(0x6a3fe5c60429),
252                 /* lg(8/7) = */ FLAC__U64L(0x315130157f7a),
253                 /* lg(16/15) = */ FLAC__U64L(0x17d60496cfbb),
254                 /* lg(32/31) = */ FLAC__U64L(0xbb9ca64ecac),
255                 /* lg(64/63) = */ FLAC__U64L(0x5d0fba187cd),
256                 /* lg(128/127) = */ FLAC__U64L(0x2e58f7441ee),
257                 /* lg(256/255) = */ FLAC__U64L(0x1720d9c06a8),
258                 /* lg(512/511) = */ FLAC__U64L(0xb8d8752173),
259                 /* lg(1024/1023) = */ FLAC__U64L(0x5c60aa252e),
260                 /* lg(2048/2047) = */ FLAC__U64L(0x2e2d71b0d8),
261                 /* lg(4096/4095) = */ FLAC__U64L(0x1716001719),
262                 /* lg(8192/8191) = */ FLAC__U64L(0xb8ad1de1b),
263                 /* lg(16384/16383) = */ FLAC__U64L(0x5c55d640d),
264                 /* lg(32768/32767) = */ FLAC__U64L(0x2e2abcf52)
265         }
266 };
267 #endif
268
269 FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, unsigned fracbits, unsigned precision)
270 {
271         const FLAC__uint32 ONE = (1u << fracbits);
272         const FLAC__uint32 *table = log2_lookup[fracbits >> 2];
273
274         FLAC__ASSERT(fracbits < 32);
275         FLAC__ASSERT((fracbits & 0x3) == 0);
276
277         if(x < ONE)
278                 return 0;
279
280         if(precision > LOG2_LOOKUP_PRECISION)
281                 precision = LOG2_LOOKUP_PRECISION;
282
283         /* Knuth's algorithm for computing logarithms, optimized for base-2 with lookup tables */
284         {
285                 FLAC__uint32 y = 0;
286                 FLAC__uint32 z = x >> 1, k = 1;
287                 while (x > ONE && k < precision) {
288                         if (x - z >= ONE) {
289                                 x -= z;
290                                 z = x >> k;
291                                 y += table[k];
292                         }
293                         else {
294                                 z >>= 1;
295                                 k++;
296                         }
297                 }
298                 return y;
299         }
300 }
301
302 #endif /* defined FLAC__INTEGER_ONLY_LIBRARY */