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
28/**
29 * fixed-point implementation of cosine in [0; PI) domain.
30 * @param arg fixed-point cosine argument, 0 <= arg < 0x4000
31 *
32 * @return value of (1<<15) * cos(arg * PI / (1<<14)), -0x8000 <= result <= 0x7fff
33 */
34int16_t ff_cos(uint16_t arg);
35
36/**
37 * fixed-point implementation of exp2(x) in [0; 1] domain.
38 * @param power argument to exp2, 0 <= power <= 0x7fff
39 *
40 * @return value of (1<<20) * exp2(power / (1<<15))
41 *         0x8000c <= result <= 0xfffea
42 */
43int ff_exp2(uint16_t power);
44
45/**
46 * Calculates log2(x).
47 * @param value function argument, 0 < value <= 7fff ffff
48 *
49 * @return value of (1<<15) * log2(value)
50 */
51int ff_log2(uint32_t value);
52
53/**
54 * Shift value left or right depending on sign of offset parameter.
55 * @param value value to shift
56 * @param offset shift offset
57 *
58 * @return value << offset, if offset>=0; value >> -offset - otherwise
59 */
60static inline int bidir_sal(int value, int offset)
61{
62    if(offset < 0) return value >> -offset;
63    else           return value <<  offset;
64}
65
66/**
67 * returns the dot product.
68 * @param a input data array
69 * @param b input data array
70 * @param length number of elements
71 *
72 * @return dot product = sum of elementwise products
73 */
74float ff_dot_productf(const float* a, const float* b, int length);
75
76#endif /* AVCODEC_CELP_MATH_H */
77