celp_math.h 2.66 KB
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/*
 * 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
 */

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#ifndef AVCODEC_CELP_MATH_H
#define AVCODEC_CELP_MATH_H
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#include <stdint.h>

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typedef struct CELPMContext {
    /**
     * Return 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
     */
    float (*dot_productf)(const float* a, const float* b, int length);

}CELPMContext;

/**
 * Initialize CELPMContext.
 */
void ff_celp_math_init(CELPMContext *c);
void ff_celp_math_init_mips(CELPMContext *c);

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

/**
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 * Calculate log2(x).
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 * @param value function argument, 0 < value <= 7fff ffff
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 *
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 * @return value of (1<<15) * log2(value)
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 */
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int ff_log2_q15(uint32_t value);
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/**
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 * Shift value left or right depending on sign of offset parameter.
 * @param value value to shift
 * @param offset shift offset
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 *
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 * @return value << offset, if offset>=0; value >> -offset - otherwise
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 */
static inline int bidir_sal(int value, int offset)
{
    if(offset < 0) return value >> -offset;
    else           return value <<  offset;
}

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/**
 * returns 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
 */
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int64_t ff_dot_product(const int16_t *a, const int16_t *b, int length);
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/**
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 * Return the dot product.
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 * @param a input data array
 * @param b input data array
 * @param length number of elements
 *
 * @return dot product = sum of elementwise products
 */
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float ff_dot_productf(const float* a, const float* b, int length);
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#endif /* AVCODEC_CELP_MATH_H */