/* * Various fixed-point math operations * * Copyright (c) 2008 Vladimir Voroshilov * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include <inttypes.h>#include <limits.h>#include <assert.h> #include "avcodec.h"#include "celp_math.h" /** * Cosine table: base_cos[i] = (1<<15) * cos(i*PI/64) */static const int16_t tab_cos[65] ={  32767,  32738,  32617,  32421,  32145,  31793,  31364,  30860,  30280,  29629,  28905,  28113,  27252,  26326,  25336,  24285,  23176,  22011,  20793,  19525,  18210,  16851,  15451,  14014,  12543,  11043,   9515,   7965,   6395,   4810,   3214,   1609,      1,  -1607,  -3211,  -4808,  -6393,  -7962,  -9513, -11040, -12541, -14012, -15449, -16848, -18207, -19523, -20791, -22009, -23174, -24283, -25334, -26324, -27250, -28111, -28904, -29627, -30279, -30858, -31363, -31792, -32144, -32419, -32616, -32736, -32768,}; static const uint16_t exp2a[]={     0,  1435,  2901,  4400,  5931,  7496,  9096, 10730, 12400, 14106, 15850, 17632, 19454, 21315, 23216, 25160, 27146, 29175, 31249, 33368, 35534, 37747, 40009, 42320, 44682, 47095, 49562, 52082, 54657, 57289, 59979, 62727,}; static const uint16_t exp2b[]={     3,   712,  1424,  2134,  2845,  3557,  4270,  4982,  5696,  6409,  7124,  7839,  8554,  9270,  9986, 10704, 11421, 12138, 12857, 13576, 14295, 15014, 15734, 16455, 17176, 17898, 18620, 19343, 20066, 20790, 21514, 22238,}; int16_t ff_cos(uint16_t arg){    uint8_t offset= arg;    uint8_t ind = arg >> 8;     assert(arg <= 0x3fff);     return tab_cos[ind] + (offset * (tab_cos[ind+1] - tab_cos[ind]) >> 8);} int ff_exp2(uint16_t power){    unsigned int result= exp2a[power>>10] + 0x10000;     assert(power <= 0x7fff);     result= (result<<3) + ((result*exp2b[(power>>5)&31])>>17);    return result + ((result*(power&31)*89)>>22);} /** * Table used to compute log2(x) * * tab_log2[i] = (1<<15) * log2(1 + i/32), i=0..32 */static const uint16_t tab_log2[33] ={      4,   1459,   2870,   4240,   5572,   6867,   8127,   9355,  10552,  11719,  12858,  13971,  15057,  16120,  17158,  18175,  19170,  20145,  21100,  22036,  22954,  23854,  24738,  25605,  26457,  27294,  28116,  28924,  29719,  30500,  31269,  32025,  32769,}; int ff_log2(uint32_t value){    uint8_t  power_int;    uint8_t  frac_x0;    uint16_t frac_dx;     // Stripping zeros from beginning    power_int = av_log2(value);    value <<= (31 - power_int);     // b31 is always non-zero now    frac_x0 = (value & 0x7c000000) >> 26; // b26-b31 and [32..63] -> [0..31]    frac_dx = (value & 0x03fff800) >> 11;     value = tab_log2[frac_x0];    value += (frac_dx * (tab_log2[frac_x0+1] - tab_log2[frac_x0])) >> 15;     return (power_int << 15) + value;} float ff_dot_productf(const float* a, const float* b, int length){    float sum = 0;    int i;     for(i=0; i<length; i++)        sum += a[i] * b[i];     return sum;}