newlib-cygwin/newlib/libm/math/w_fmod.c

108 lines
2.3 KiB
C

/* @(#)w_fmod.c 5.1 93/09/24 */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
/*
FUNCTION
<<fmod>>, <<fmodf>>---floating-point remainder (modulo)
INDEX
fmod
INDEX
fmodf
ANSI_SYNOPSIS
#include <math.h>
double fmod(double <[x]>, double <[y]>)
float fmodf(float <[x]>, float <[y]>)
TRAD_SYNOPSIS
#include <math.h>
double fmod(<[x]>, <[y]>)
double (<[x]>, <[y]>);
float fmodf(<[x]>, <[y]>)
float (<[x]>, <[y]>);
DESCRIPTION
The <<fmod>> and <<fmodf>> functions compute the floating-point
remainder of <[x]>/<[y]> (<[x]> modulo <[y]>).
RETURNS
The <<fmod>> function returns the value
@ifnottex
<[x]>-<[i]>*<[y]>,
@end ifnottex
@tex
$x-i\times y$,
@end tex
for the largest integer <[i]> such that, if <[y]> is nonzero, the
result has the same sign as <[x]> and magnitude less than the
magnitude of <[y]>.
<<fmod(<[x]>,0)>> returns NaN, and sets <<errno>> to <<EDOM>>.
You can modify error treatment for these functions using <<matherr>>.
PORTABILITY
<<fmod>> is ANSI C. <<fmodf>> is an extension.
*/
/*
* wrapper fmod(x,y)
*/
#include "fdlibm.h"
#include <errno.h>
#ifndef _DOUBLE_IS_32BITS
#ifdef __STDC__
double fmod(double x, double y) /* wrapper fmod */
#else
double fmod(x,y) /* wrapper fmod */
double x,y;
#endif
{
#ifdef _IEEE_LIBM
return __ieee754_fmod(x,y);
#else
double z;
struct exception exc;
z = __ieee754_fmod(x,y);
if(_LIB_VERSION == _IEEE_ ||isnan(y)||isnan(x)) return z;
if(y==0.0) {
/* fmod(x,0) */
exc.type = DOMAIN;
exc.name = "fmod";
exc.arg1 = x;
exc.arg2 = y;
exc.err = 0;
if (_LIB_VERSION == _SVID_)
exc.retval = x;
else
exc.retval = 0.0/0.0;
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
errno = EDOM;
}
if (exc.err != 0)
errno = exc.err;
return exc.retval;
} else
return z;
#endif
}
#endif /* defined(_DOUBLE_IS_32BITS) */