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