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/*
* This file contains math functions missing from the Cephes library.
*
* May 22, 2001 Manuel Novoa III
*
* Added modf and fmod.
*
* TODO:
* Break out functions into seperate object files as is done
* by (for example) stdio. Also do this with cephes files.
*/
#include <math.h>
#include <errno.h>
#undef UNK
/* Set this to nonzero to enable a couple of shortcut tests in fmod. */
#define SPEED_OVER_SIZE 0
/**********************************************************************/
double modf(double x, double *iptr)
{
double y;
#ifdef UNK
mtherr( "modf", DOMAIN );
*iptr = NAN;
return NAN;
#endif
#ifdef NANS
if( isnan(x) ) {
*iptr = x;
return x;
}
#endif
#ifdef INFINITIES
if(!isfinite(x)) {
*iptr = x; /* Matches glibc, but returning NAN */
return 0; /* makes more sense to me... */
}
#endif
if (x < 0) { /* Round towards 0. */
y = ceil(x);
} else {
y = floor(x);
}
*iptr = y;
return x - y;
}
/**********************************************************************/
extern double NAN;
double fmod(double x, double y)
{
double z;
int negative, ex, ey;
#ifdef UNK
mtherr( "fmod", DOMAIN );
return NAN;
#endif
#ifdef NANS
if( isnan(x) || isnan(y) ) {
errno = EDOM;
return NAN;
}
#endif
if (y == 0) {
errno = EDOM;
return NAN;
}
#ifdef INFINITIES
if(!isfinite(x)) {
errno = EDOM;
return NAN;
}
#if SPEED_OVER_SIZE
if(!isfinite(y)) {
return x;
}
#endif
#endif
#if SPEED_OVER_SIZE
if (x == 0) {
return 0;
}
#endif
negative = 0;
if (x < 0) {
negative = 1;
x = -x;
}
if (y < 0) {
y = -y;
}
frexp(y,&ey);
while (x >= y) {
frexp(x,&ex);
z = ldexp(y,ex-ey);
if (z > x) {
z /= 2;
}
x -= z;
}
if (negative) {
return -x;
} else {
return x;
}
}
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