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/*
* 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
*/
#ifndef AVCODEC_CELP_MATH_H
#define AVCODEC_CELP_MATH_H
#include <stdint.h>
/**
* fixed-point implementation of exp2(x) in [0; 1] domain.
* @param power argument to exp2, 0 <= power <= 0x7fff
*
* @return value of (1<<20) * exp2(power / (1<<15))
* 0x8000c <= result <= 0xfffea
*/
int ff_exp2(uint16_t power);
/**
* Calculate log2(x).
* @param value function argument, 0 < value <= 7fff ffff
*
* @return value of (1<<15) * log2(value)
*/
int ff_log2_q15(uint32_t value);
/**
* Calculate the dot product of 2 int16_t vectors.
* @param a input data array
* @param b input data array
* @param length number of elements
*
* @return dot product = sum of elementwise products
*/
int64_t ff_dot_product(const int16_t *a, const int16_t *b, int length);
/**
* Shift value left or right depending on sign of offset parameter.
* @param value value to shift
* @param offset shift offset
*
* @return value << offset, if offset>=0; value >> -offset - otherwise
*/
static inline int bidir_sal(int value, int offset)
{
if(offset < 0) return value >> -offset;
else return value << offset;
}
#endif /* AVCODEC_CELP_MATH_H */
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