xref: /third_party/ffmpeg/libavcodec/celp_math.h (revision cabdff1a) 
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#ifndef AVCODEC_CELP_MATH_H
24#define AVCODEC_CELP_MATH_H
25
26#include <stdint.h>
27
28typedef struct CELPMContext {
29    /**
30     * Return the dot product.
31     * @param a input data array
32     * @param b input data array
33     * @param length number of elements
34     *
35     * @return dot product = sum of elementwise products
36     */
37    float (*dot_productf)(const float* a, const float* b, int length);
38
39}CELPMContext;
40
41/**
42 * Initialize CELPMContext.
43 */
44void ff_celp_math_init(CELPMContext *c);
45void ff_celp_math_init_mips(CELPMContext *c);
46
47/**
48 * fixed-point implementation of exp2(x) in [0; 1] domain.
49 * @param power argument to exp2, 0 <= power <= 0x7fff
50 *
51 * @return value of (1<<20) * exp2(power / (1<<15))
52 *         0x8000c <= result <= 0xfffea
53 */
54int ff_exp2(uint16_t power);
55
56/**
57 * Calculate log2(x).
58 * @param value function argument, 0 < value <= 7fff ffff
59 *
60 * @return value of (1<<15) * log2(value)
61 */
62int ff_log2_q15(uint32_t value);
63
64/**
65 * Calculate the dot product of 2 int16_t vectors.
66 * @param a input data array
67 * @param b input data array
68 * @param length number of elements
69 *
70 * @return dot product = sum of elementwise products
71 */
72int64_t ff_dot_product(const int16_t *a, const int16_t *b, int length);
73
74/**
75 * Shift value left or right depending on sign of offset parameter.
76 * @param value value to shift
77 * @param offset shift offset
78 *
79 * @return value << offset, if offset>=0; value >> -offset - otherwise
80 */
81static inline unsigned bidir_sal(unsigned value, int offset)
82{
83    if(offset < 0) return value >> -offset;
84    else           return value <<  offset;
85}
86
87/**
88 * Return the dot product.
89 * @param a input data array
90 * @param b input data array
91 * @param length number of elements
92 *
93 * @return dot product = sum of elementwise products
94 */
95float ff_dot_productf(const float* a, const float* b, int length);
96
97#endif /* AVCODEC_CELP_MATH_H */
98