FFmpeg  4.4.6
celp_math.c
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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 #ifdef G729_BITEXACT
33 static const uint16_t exp2a[]=
34 {
35  0, 1435, 2901, 4400, 5931, 7496, 9096, 10730,
36  12400, 14106, 15850, 17632, 19454, 21315, 23216, 25160,
37  27146, 29175, 31249, 33368, 35534, 37747, 40009, 42320,
38  44682, 47095, 49562, 52082, 54657, 57289, 59979, 62727,
39 };
40 
41 static const uint16_t exp2b[]=
42 {
43  3, 712, 1424, 2134, 2845, 3557, 4270, 4982,
44  5696, 6409, 7124, 7839, 8554, 9270, 9986, 10704,
45  11421, 12138, 12857, 13576, 14295, 15014, 15734, 16455,
46  17176, 17898, 18620, 19343, 20066, 20790, 21514, 22238,
47 };
48 
49 int ff_exp2(uint16_t power)
50 {
51  unsigned int result= exp2a[power>>10] + 0x10000;
52 
53  av_assert2(power <= 0x7fff);
54 
55  result= (result<<3) + ((result*exp2b[(power>>5)&31])>>17);
56  return result + ((result*(power&31)*89)>>22);
57 }
58 #endif
59 
60 /**
61  * Table used to compute log2(x)
62  *
63  * tab_log2[i] = (1<<15) * log2(1 + i/32), i=0..32
64  */
65 static const uint16_t tab_log2[33] =
66 {
67 #ifdef G729_BITEXACT
68  0, 1455, 2866, 4236, 5568, 6863, 8124, 9352,
69  10549, 11716, 12855, 13967, 15054, 16117, 17156, 18172,
70  19167, 20142, 21097, 22033, 22951, 23852, 24735, 25603,
71  26455, 27291, 28113, 28922, 29716, 30497, 31266, 32023, 32767,
72 #else
73  4, 1459, 2870, 4240, 5572, 6867, 8127, 9355,
74  10552, 11719, 12858, 13971, 15057, 16120, 17158, 18175,
75  19170, 20145, 21100, 22036, 22954, 23854, 24738, 25605,
76  26457, 27294, 28116, 28924, 29719, 30500, 31269, 32025, 32769,
77 #endif
78 };
79 
80 int ff_log2_q15(uint32_t value)
81 {
82  uint8_t power_int;
83  uint8_t frac_x0;
84  uint16_t frac_dx;
85 
86  // Stripping zeros from beginning
87  power_int = av_log2(value);
88  value <<= (31 - power_int);
89 
90  // b31 is always non-zero now
91  frac_x0 = (value & 0x7c000000) >> 26; // b26-b31 and [32..63] -> [0..31]
92  frac_dx = (value & 0x03fff800) >> 11;
93 
94  value = tab_log2[frac_x0];
95  value += (frac_dx * (tab_log2[frac_x0+1] - tab_log2[frac_x0])) >> 15;
96 
97  return (power_int << 15) + value;
98 }
99 
100 int64_t ff_dot_product(const int16_t *a, const int16_t *b, int length)
101 {
102  int i;
103  int64_t sum = 0;
104 
105  for (i = 0; i < length; i++)
106  sum += MUL16(a[i], b[i]);
107 
108  return sum;
109 }
110 
111 float ff_dot_productf(const float* a, const float* b, int length)
112 {
113  float sum = 0;
114  int i;
115 
116  for(i=0; i<length; i++)
117  sum += a[i] * b[i];
118 
119  return sum;
120 }
121 
123 {
124  c->dot_productf = ff_dot_productf;
125 
126  if(HAVE_MIPSFPU)
128 }
uint8_t
simple assert() macros that are a bit more flexible than ISO C assert().
#define av_assert2(cond)
assert() equivalent, that does lie in speed critical code.
Definition: avassert.h:64
Libavcodec external API header.
int64_t ff_dot_product(const int16_t *a, const int16_t *b, int length)
Calculate the dot product of 2 int16_t vectors.
Definition: celp_math.c:100
void ff_celp_math_init(CELPMContext *c)
Initialize CELPMContext.
Definition: celp_math.c:122
int ff_log2_q15(uint32_t value)
Calculate log2(x).
Definition: celp_math.c:80
static const uint16_t tab_log2[33]
Table used to compute log2(x)
Definition: celp_math.c:65
float ff_dot_productf(const float *a, const float *b, int length)
Return the dot product.
Definition: celp_math.c:111
int ff_exp2(uint16_t power)
fixed-point implementation of exp2(x) in [0; 1] domain.
void ff_celp_math_init_mips(CELPMContext *c)
common internal and external API header
#define HAVE_MIPSFPU
Definition: config.h:76
long long int64_t
Definition: coverity.c:34
double value
Definition: eval.c:98
int i
Definition: input.c:407
#define av_log2
Definition: intmath.h:83
#define MUL16(ra, rb)
Definition: mathops.h:88
const char * b
Definition: vf_curves.c:118
static double c[64]