[pcsx_rearmed.git] / deps / flac-1.3.2 / src / libFLAC / float.c

/* libFLAC - Free Lossless Audio Codec library
 * Copyright (C) 2004-2009  Josh Coalson
 * Copyright (C) 2011-2016  Xiph.Org Foundation
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of the Xiph.org Foundation nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include "FLAC/assert.h"
#include "share/compat.h"
#include "private/float.h"

#ifdef FLAC__INTEGER_ONLY_LIBRARY

const FLAC__fixedpoint FLAC__FP_ZERO = 0;
const FLAC__fixedpoint FLAC__FP_ONE_HALF = 0x00008000;
const FLAC__fixedpoint FLAC__FP_ONE = 0x00010000;
const FLAC__fixedpoint FLAC__FP_LN2 = 45426;
const FLAC__fixedpoint FLAC__FP_E = 178145;

/* Lookup tables for Knuth's logarithm algorithm */
#define LOG2_LOOKUP_PRECISION 16
static const FLAC__uint32 log2_lookup[][LOG2_LOOKUP_PRECISION] = {
	{
		/*
		 * 0 fraction bits
		 */
		/* undefined */ 0x00000000,
		/* lg(2/1) = */ 0x00000001,
		/* lg(4/3) = */ 0x00000000,
		/* lg(8/7) = */ 0x00000000,
		/* lg(16/15) = */ 0x00000000,
		/* lg(32/31) = */ 0x00000000,
		/* lg(64/63) = */ 0x00000000,
		/* lg(128/127) = */ 0x00000000,
		/* lg(256/255) = */ 0x00000000,
		/* lg(512/511) = */ 0x00000000,
		/* lg(1024/1023) = */ 0x00000000,
		/* lg(2048/2047) = */ 0x00000000,
		/* lg(4096/4095) = */ 0x00000000,
		/* lg(8192/8191) = */ 0x00000000,
		/* lg(16384/16383) = */ 0x00000000,
		/* lg(32768/32767) = */ 0x00000000
	},
	{
		/*
		 * 4 fraction bits
		 */
		/* undefined */ 0x00000000,
		/* lg(2/1) = */ 0x00000010,
		/* lg(4/3) = */ 0x00000007,
		/* lg(8/7) = */ 0x00000003,
		/* lg(16/15) = */ 0x00000001,
		/* lg(32/31) = */ 0x00000001,
		/* lg(64/63) = */ 0x00000000,
		/* lg(128/127) = */ 0x00000000,
		/* lg(256/255) = */ 0x00000000,
		/* lg(512/511) = */ 0x00000000,
		/* lg(1024/1023) = */ 0x00000000,
		/* lg(2048/2047) = */ 0x00000000,
		/* lg(4096/4095) = */ 0x00000000,
		/* lg(8192/8191) = */ 0x00000000,
		/* lg(16384/16383) = */ 0x00000000,
		/* lg(32768/32767) = */ 0x00000000
	},
	{
		/*
		 * 8 fraction bits
		 */
		/* undefined */ 0x00000000,
		/* lg(2/1) = */ 0x00000100,
		/* lg(4/3) = */ 0x0000006a,
		/* lg(8/7) = */ 0x00000031,
		/* lg(16/15) = */ 0x00000018,
		/* lg(32/31) = */ 0x0000000c,
		/* lg(64/63) = */ 0x00000006,
		/* lg(128/127) = */ 0x00000003,
		/* lg(256/255) = */ 0x00000001,
		/* lg(512/511) = */ 0x00000001,
		/* lg(1024/1023) = */ 0x00000000,
		/* lg(2048/2047) = */ 0x00000000,
		/* lg(4096/4095) = */ 0x00000000,
		/* lg(8192/8191) = */ 0x00000000,
		/* lg(16384/16383) = */ 0x00000000,
		/* lg(32768/32767) = */ 0x00000000
	},
	{
		/*
		 * 12 fraction bits
		 */
		/* undefined */ 0x00000000,
		/* lg(2/1) = */ 0x00001000,
		/* lg(4/3) = */ 0x000006a4,
		/* lg(8/7) = */ 0x00000315,
		/* lg(16/15) = */ 0x0000017d,
		/* lg(32/31) = */ 0x000000bc,
		/* lg(64/63) = */ 0x0000005d,
		/* lg(128/127) = */ 0x0000002e,
		/* lg(256/255) = */ 0x00000017,
		/* lg(512/511) = */ 0x0000000c,
		/* lg(1024/1023) = */ 0x00000006,
		/* lg(2048/2047) = */ 0x00000003,
		/* lg(4096/4095) = */ 0x00000001,
		/* lg(8192/8191) = */ 0x00000001,
		/* lg(16384/16383) = */ 0x00000000,
		/* lg(32768/32767) = */ 0x00000000
	},
	{
		/*
		 * 16 fraction bits
		 */
		/* undefined */ 0x00000000,
		/* lg(2/1) = */ 0x00010000,
		/* lg(4/3) = */ 0x00006a40,
		/* lg(8/7) = */ 0x00003151,
		/* lg(16/15) = */ 0x000017d6,
		/* lg(32/31) = */ 0x00000bba,
		/* lg(64/63) = */ 0x000005d1,
		/* lg(128/127) = */ 0x000002e6,
		/* lg(256/255) = */ 0x00000172,
		/* lg(512/511) = */ 0x000000b9,
		/* lg(1024/1023) = */ 0x0000005c,
		/* lg(2048/2047) = */ 0x0000002e,
		/* lg(4096/4095) = */ 0x00000017,
		/* lg(8192/8191) = */ 0x0000000c,
		/* lg(16384/16383) = */ 0x00000006,
		/* lg(32768/32767) = */ 0x00000003
	},
	{
		/*
		 * 20 fraction bits
		 */
		/* undefined */ 0x00000000,
		/* lg(2/1) = */ 0x00100000,
		/* lg(4/3) = */ 0x0006a3fe,
		/* lg(8/7) = */ 0x00031513,
		/* lg(16/15) = */ 0x00017d60,
		/* lg(32/31) = */ 0x0000bb9d,
		/* lg(64/63) = */ 0x00005d10,
		/* lg(128/127) = */ 0x00002e59,
		/* lg(256/255) = */ 0x00001721,
		/* lg(512/511) = */ 0x00000b8e,
		/* lg(1024/1023) = */ 0x000005c6,
		/* lg(2048/2047) = */ 0x000002e3,
		/* lg(4096/4095) = */ 0x00000171,
		/* lg(8192/8191) = */ 0x000000b9,
		/* lg(16384/16383) = */ 0x0000005c,
		/* lg(32768/32767) = */ 0x0000002e
	},
	{
		/*
		 * 24 fraction bits
		 */
		/* undefined */ 0x00000000,
		/* lg(2/1) = */ 0x01000000,
		/* lg(4/3) = */ 0x006a3fe6,
		/* lg(8/7) = */ 0x00315130,
		/* lg(16/15) = */ 0x0017d605,
		/* lg(32/31) = */ 0x000bb9ca,
		/* lg(64/63) = */ 0x0005d0fc,
		/* lg(128/127) = */ 0x0002e58f,
		/* lg(256/255) = */ 0x0001720e,
		/* lg(512/511) = */ 0x0000b8d8,
		/* lg(1024/1023) = */ 0x00005c61,
		/* lg(2048/2047) = */ 0x00002e2d,
		/* lg(4096/4095) = */ 0x00001716,
		/* lg(8192/8191) = */ 0x00000b8b,
		/* lg(16384/16383) = */ 0x000005c5,
		/* lg(32768/32767) = */ 0x000002e3
	},
	{
		/*
		 * 28 fraction bits
		 */
		/* undefined */ 0x00000000,
		/* lg(2/1) = */ 0x10000000,
		/* lg(4/3) = */ 0x06a3fe5c,
		/* lg(8/7) = */ 0x03151301,
		/* lg(16/15) = */ 0x017d6049,
		/* lg(32/31) = */ 0x00bb9ca6,
		/* lg(64/63) = */ 0x005d0fba,
		/* lg(128/127) = */ 0x002e58f7,
		/* lg(256/255) = */ 0x001720da,
		/* lg(512/511) = */ 0x000b8d87,
		/* lg(1024/1023) = */ 0x0005c60b,
		/* lg(2048/2047) = */ 0x0002e2d7,
		/* lg(4096/4095) = */ 0x00017160,
		/* lg(8192/8191) = */ 0x0000b8ad,
		/* lg(16384/16383) = */ 0x00005c56,
		/* lg(32768/32767) = */ 0x00002e2b
	}
};

#if 0
static const FLAC__uint64 log2_lookup_wide[] = {
	{
		/*
		 * 32 fraction bits
		 */
		/* undefined */ 0x00000000,
		/* lg(2/1) = */ FLAC__U64L(0x100000000),
		/* lg(4/3) = */ FLAC__U64L(0x6a3fe5c6),
		/* lg(8/7) = */ FLAC__U64L(0x31513015),
		/* lg(16/15) = */ FLAC__U64L(0x17d60497),
		/* lg(32/31) = */ FLAC__U64L(0x0bb9ca65),
		/* lg(64/63) = */ FLAC__U64L(0x05d0fba2),
		/* lg(128/127) = */ FLAC__U64L(0x02e58f74),
		/* lg(256/255) = */ FLAC__U64L(0x01720d9c),
		/* lg(512/511) = */ FLAC__U64L(0x00b8d875),
		/* lg(1024/1023) = */ FLAC__U64L(0x005c60aa),
		/* lg(2048/2047) = */ FLAC__U64L(0x002e2d72),
		/* lg(4096/4095) = */ FLAC__U64L(0x00171600),
		/* lg(8192/8191) = */ FLAC__U64L(0x000b8ad2),
		/* lg(16384/16383) = */ FLAC__U64L(0x0005c55d),
		/* lg(32768/32767) = */ FLAC__U64L(0x0002e2ac)
	},
	{
		/*
		 * 48 fraction bits
		 */
		/* undefined */ 0x00000000,
		/* lg(2/1) = */ FLAC__U64L(0x1000000000000),
		/* lg(4/3) = */ FLAC__U64L(0x6a3fe5c60429),
		/* lg(8/7) = */ FLAC__U64L(0x315130157f7a),
		/* lg(16/15) = */ FLAC__U64L(0x17d60496cfbb),
		/* lg(32/31) = */ FLAC__U64L(0xbb9ca64ecac),
		/* lg(64/63) = */ FLAC__U64L(0x5d0fba187cd),
		/* lg(128/127) = */ FLAC__U64L(0x2e58f7441ee),
		/* lg(256/255) = */ FLAC__U64L(0x1720d9c06a8),
		/* lg(512/511) = */ FLAC__U64L(0xb8d8752173),
		/* lg(1024/1023) = */ FLAC__U64L(0x5c60aa252e),
		/* lg(2048/2047) = */ FLAC__U64L(0x2e2d71b0d8),
		/* lg(4096/4095) = */ FLAC__U64L(0x1716001719),
		/* lg(8192/8191) = */ FLAC__U64L(0xb8ad1de1b),
		/* lg(16384/16383) = */ FLAC__U64L(0x5c55d640d),
		/* lg(32768/32767) = */ FLAC__U64L(0x2e2abcf52)
	}
};
#endif

FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, unsigned fracbits, unsigned precision)
{
	const FLAC__uint32 ONE = (1u << fracbits);
	const FLAC__uint32 *table = log2_lookup[fracbits >> 2];

	FLAC__ASSERT(fracbits < 32);
	FLAC__ASSERT((fracbits & 0x3) == 0);

	if(x < ONE)
		return 0;

	if(precision > LOG2_LOOKUP_PRECISION)
		precision = LOG2_LOOKUP_PRECISION;

	/* Knuth's algorithm for computing logarithms, optimized for base-2 with lookup tables */
	{
		FLAC__uint32 y = 0;
		FLAC__uint32 z = x >> 1, k = 1;
		while (x > ONE && k < precision) {
			if (x - z >= ONE) {
				x -= z;
				z = x >> k;
				y += table[k];
			}
			else {
				z >>= 1;
				k++;
			}
		}
		return y;
	}
}

#endif /* defined FLAC__INTEGER_ONLY_LIBRARY */
Commit	Line	Data
ce188d4d	1	/* libFLAC - Free Lossless Audio Codec library
	2	* Copyright (C) 2004-2009 Josh Coalson
	3	* Copyright (C) 2011-2016 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 */