celp_math.h 2.17 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
/*
 * Various fixed-point math operations
 *
 * Copyright (c) 2008 Vladimir Voroshilov
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

23 24
#ifndef AVCODEC_CELP_MATH_H
#define AVCODEC_CELP_MATH_H
25

26 27
#include <stdint.h>

28
/**
29 30
 * fixed-point implementation of cosine in [0; PI) domain.
 * @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 34 35 36
 */
int16_t ff_cos(uint16_t arg);

/**
37 38
 * fixed-point implementation of exp2(x) in [0; 1] domain.
 * @param power argument to exp2, 0 <= power <= 0x7fff
39
 *
40
 * @return value of (1<<20) * exp2(power / (1<<15))
41 42 43 44 45
 *         0x8000c <= result <= 0xfffea
 */
int ff_exp2(uint16_t power);

/**
46 47
 * Calculates log2(x).
 * @param value function argument, 0 < value <= 7fff ffff
48
 *
49
 * @return value of (1<<15) * log2(value)
50 51 52
 */
int ff_log2(uint32_t value);

53
/**
54 55 56
 * Shift value left or right depending on sign of offset parameter.
 * @param value value to shift
 * @param offset shift offset
57
 *
58
 * @return value << offset, if offset>=0; value >> -offset - otherwise
59 60 61 62 63 64 65
 */
static inline int bidir_sal(int value, int offset)
{
    if(offset < 0) return value >> -offset;
    else           return value <<  offset;
}

66 67 68 69 70 71 72 73
/**
 * returns the dot product.
 * @param a input data array
 * @param b input data array
 * @param length number of elements
 *
 * @return dot product = sum of elementwise products
 */
74
float ff_dot_productf(const float* a, const float* b, int length);
75

76
#endif /* AVCODEC_CELP_MATH_H */