libavcodec/celp_math.h

   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 typedef struct CELPMContext {
  29     /**
  30      * Return the dot product.
  31      * @param a input data array
  32      * @param b input data array
  33      * @param length number of elements
  34      *
  35      * @return dot product = sum of elementwise products
  36      */
  37     float (*dot_productf)(const float* a, const float* b, int length);
  38
  39 }CELPMContext;
  40
  41 /**
  42  * Initialize CELPMContext.
  43  */
  44 void ff_celp_math_init(CELPMContext *c);
  45 void ff_celp_math_init_mips(CELPMContext *c);
  46
  47 /**
  48  * fixed-point implementation of exp2(x) in [0; 1] domain.
  49  * @param power argument to exp2, 0 <= power <= 0x7fff
  50  *
  51  * @return value of (1<<20) * exp2(power / (1<<15))
  52  *         0x8000c <= result <= 0xfffea
  53  */
  54 int ff_exp2(uint16_t power);
  55
  56 /**
  57  * Calculate log2(x).
  58  * @param value function argument, 0 < value <= 7fff ffff
  59  *
  60  * @return value of (1<<15) * log2(value)
  61  */
  62 int ff_log2_q15(uint32_t value);
  63
  64 /**
  65  * Calculate the dot product of 2 int16_t vectors.
  66  * @param a input data array
  67  * @param b input data array
  68  * @param length number of elements
  69  *
  70  * @return dot product = sum of elementwise products
  71  */
  72 int64_t ff_dot_product(const int16_t *a, const int16_t *b, int length);
  73
  74 /**
  75  * Shift value left or right depending on sign of offset parameter.
  76  * @param value value to shift
  77  * @param offset shift offset
  78  *
  79  * @return value << offset, if offset>=0; value >> -offset - otherwise
  80  */
  81 static inline unsigned bidir_sal(unsigned value, int offset)
  82 {
  83     if(offset < 0) return value >> -offset;
  84     else           return value <<  offset;
  85 }
  86
  87 /**
  88  * Return the dot product.
  89  * @param a input data array
  90  * @param b input data array
  91  * @param length number of elements
  92  *
  93  * @return dot product = sum of elementwise products
  94  */
  95 float ff_dot_productf(const float* a, const float* b, int length);
  96
  97 #endif /* AVCODEC_CELP_MATH_H */