math_approx.h

00001 /* Copyright (C) 2002 Jean-Marc Valin */
00002 /**
00003    @file math_approx.h
00004    @brief Various math approximation functions for Speex
00005 */
00006 /*
00007    Redistribution and use in source and binary forms, with or without
00008    modification, are permitted provided that the following conditions
00009    are met:
00010    
00011    - Redistributions of source code must retain the above copyright
00012    notice, this list of conditions and the following disclaimer.
00013    
00014    - Redistributions in binary form must reproduce the above copyright
00015    notice, this list of conditions and the following disclaimer in the
00016    documentation and/or other materials provided with the distribution.
00017    
00018    - Neither the name of the Xiph.org Foundation nor the names of its
00019    contributors may be used to endorse or promote products derived from
00020    this software without specific prior written permission.
00021    
00022    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00023    ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00024    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
00025    A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
00026    CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00027    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
00028    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
00029    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
00030    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
00031    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00032    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00033 */
00034 
00035 #ifndef MATH_APPROX_H
00036 #define MATH_APPROX_H
00037 
00038 #include "misc.h"
00039 
00040 spx_word16_t spx_cos(spx_word16_t x);
00041 spx_int16_t spx_ilog2(spx_uint32_t x);
00042 spx_int16_t spx_ilog4(spx_uint32_t x);
00043 #ifdef FIXED_POINT
00044 spx_word16_t spx_sqrt(spx_word32_t x);
00045 spx_word16_t spx_acos(spx_word16_t x);
00046 spx_word32_t spx_exp(spx_word16_t x);
00047 spx_word16_t spx_cos_norm(spx_word32_t x);
00048 
00049 /* Input in Q15, output in Q14 */
00050 spx_word16_t spx_atan(spx_word32_t x);
00051 
00052 #else
00053 
00054 #define spx_sqrt sqrt
00055 #define spx_acos acos
00056 #define spx_exp exp
00057 #define spx_cos_norm(x) (cos((.5f*M_PI)*(x)))
00058 #define spx_atan atan
00059 
00060 #endif
00061 
00062 #endif