Imported Debian version 2.5.3~trusty1
[deb_ffmpeg.git] / ffmpeg / libavcodec / celp_math.c
1 /*
2 * Various fixed-point math operations
3 *
4 * Copyright (c) 2008 Vladimir Voroshilov
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include <inttypes.h>
24 #include <limits.h>
25
26 #include "libavutil/avassert.h"
27 #include "avcodec.h"
28 #include "mathops.h"
29 #include "celp_math.h"
30 #include "libavutil/common.h"
31
32 static const uint16_t exp2a[]=
33 {
34 0, 1435, 2901, 4400, 5931, 7496, 9096, 10730,
35 12400, 14106, 15850, 17632, 19454, 21315, 23216, 25160,
36 27146, 29175, 31249, 33368, 35534, 37747, 40009, 42320,
37 44682, 47095, 49562, 52082, 54657, 57289, 59979, 62727,
38 };
39
40 static const uint16_t exp2b[]=
41 {
42 3, 712, 1424, 2134, 2845, 3557, 4270, 4982,
43 5696, 6409, 7124, 7839, 8554, 9270, 9986, 10704,
44 11421, 12138, 12857, 13576, 14295, 15014, 15734, 16455,
45 17176, 17898, 18620, 19343, 20066, 20790, 21514, 22238,
46 };
47
48 int ff_exp2(uint16_t power)
49 {
50 unsigned int result= exp2a[power>>10] + 0x10000;
51
52 av_assert2(power <= 0x7fff);
53
54 result= (result<<3) + ((result*exp2b[(power>>5)&31])>>17);
55 return result + ((result*(power&31)*89)>>22);
56 }
57
58 /**
59 * Table used to compute log2(x)
60 *
61 * tab_log2[i] = (1<<15) * log2(1 + i/32), i=0..32
62 */
63 static const uint16_t tab_log2[33] =
64 {
65 #ifdef G729_BITEXACT
66 0, 1455, 2866, 4236, 5568, 6863, 8124, 9352,
67 10549, 11716, 12855, 13967, 15054, 16117, 17156, 18172,
68 19167, 20142, 21097, 22033, 22951, 23852, 24735, 25603,
69 26455, 27291, 28113, 28922, 29716, 30497, 31266, 32023, 32767,
70 #else
71 4, 1459, 2870, 4240, 5572, 6867, 8127, 9355,
72 10552, 11719, 12858, 13971, 15057, 16120, 17158, 18175,
73 19170, 20145, 21100, 22036, 22954, 23854, 24738, 25605,
74 26457, 27294, 28116, 28924, 29719, 30500, 31269, 32025, 32769,
75 #endif
76 };
77
78 int ff_log2_q15(uint32_t value)
79 {
80 uint8_t power_int;
81 uint8_t frac_x0;
82 uint16_t frac_dx;
83
84 // Stripping zeros from beginning
85 power_int = av_log2(value);
86 value <<= (31 - power_int);
87
88 // b31 is always non-zero now
89 frac_x0 = (value & 0x7c000000) >> 26; // b26-b31 and [32..63] -> [0..31]
90 frac_dx = (value & 0x03fff800) >> 11;
91
92 value = tab_log2[frac_x0];
93 value += (frac_dx * (tab_log2[frac_x0+1] - tab_log2[frac_x0])) >> 15;
94
95 return (power_int << 15) + value;
96 }
97
98 int64_t ff_dot_product(const int16_t *a, const int16_t *b, int length)
99 {
100 int i;
101 int64_t sum = 0;
102
103 for (i = 0; i < length; i++)
104 sum += MUL16(a[i], b[i]);
105
106 return sum;
107 }
108
109 float ff_dot_productf(const float* a, const float* b, int length)
110 {
111 float sum = 0;
112 int i;
113
114 for(i=0; i<length; i++)
115 sum += a[i] * b[i];
116
117 return sum;
118 }
119
120 void ff_celp_math_init(CELPMContext *c)
121 {
122 c->dot_productf = ff_dot_productf;
123
124 if(HAVE_MIPSFPU)
125 ff_celp_math_init_mips(c);
126 }