Show misc_math.c syntax highlighted
/*
*
* Copyright (c) 2003 The Regents of the University of California. All
* rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Neither the name of the University nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
/*
* simple math functions
*
* $Id: misc_math.c,v 1.7 2005/08/26 05:33:25 girod Exp $
*/
#ifdef EASYBUILD
# include "libmisc/include/misc_math.h"
#else
# include "misc.h"
#endif
char misc_math_c_cvsid[] = "$Id: misc_math.c,v 1.7 2005/08/26 05:33:25 girod Exp $";
/*
* given an int, this function returns the next higher int that is a
* power of 2. For example, 9 returns 16; 16 returns 16; 17 returns
* 32.
*
* Anything <= 0 returns 1.
*/
int exponential_roundup(int size)
{
int num_shifts = 0, orig_size = size;
if (size <= 0)
return 1;
while (size) {
size >>= 1;
num_shifts++;
}
/* this works only if it happened to be a power of 2 */
size = 1 << (num_shifts-1);
/* if there's a remainder, go one higher */
if (size < orig_size)
size <<= 1;
return size;
}
/*
* Fixed point math
*/
/* frac / any */
fix_32_32_t fix_div_ff(fix_32_32_t x, fix_32_32_t y)
{
return (x<<32)/y;
}
/* small int / frac */
fix_32_32_t fix_div_sf(fix_32_32_t x, fix_32_32_t y)
{
return (x<<16)/(y>>16);
}
/* frac * frac */
fix_32_32_t fix_mult_ff(fix_32_32_t x, fix_32_32_t y)
{
return (x*y)>>32;
}
/* small+frac * small+frac */
fix_32_32_t fix_mult_ss(fix_32_32_t x, fix_32_32_t y)
{
return ((x>>8)*(y>>8))>>16;
}
/* int * frac */
fix_32_32_t fix_mult_if(int64_t x, fix_32_32_t y)
{
return (x*y);
}
int64_t fix2int(fix_32_32_t x)
{
return x>>32;
}
fix_32_32_t int2fix(int64_t x)
{
return x<<32;
}
double fix2double(fix_32_32_t x)
{
return (double)x/(double)(((int64_t)1)<<32);
}
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