/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Communicator client code, released
* March 31, 1998.
*
* The Initial Developer of the Original Code is
* Sun Microsystems, Inc.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/* @(#)s_modf.c 1.3 95/01/18 */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunSoft, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
/*
* modf(double x, double *iptr)
* return fraction part of x, and return x's integral part in *iptr.
* Method:
* Bit twiddling.
*
* Exception:
* No exception.
*/
#include "fdlibm.h"
#ifdef __STDC__
static const double one = 1.0;
#else
static double one = 1.0;
#endif
#ifdef __STDC__
double fd_modf(double x, double *iptr)
#else
double fd_modf(x, iptr)
double x,*iptr;
#endif
{
int i0,i1,j0;
unsigned i;
fd_twoints u;
u.d = x;
i0 = __HI(u); /* high x */
i1 = __LO(u); /* low x */
j0 = ((i0>>20)&0x7ff)-0x3ff; /* exponent of x */
if(j0<20) { /* integer part in high x */
if(j0<0) { /* |x|<1 */
u.d = *iptr;
__HI(u) = i0&0x80000000;
__LO(u) = 0; /* *iptr = +-0 */
*iptr = u.d;
return x;
} else {
i = (0x000fffff)>>j0;
if(((i0&i)|i1)==0) { /* x is integral */
*iptr = x;
u.d = x;
__HI(u) &= 0x80000000;
__LO(u) = 0; /* return +-0 */
x = u.d;
return x;
} else {
u.d = *iptr;
__HI(u) = i0&(~i);
__LO(u) = 0;
*iptr = u.d;
return x - *iptr;
}
}
} else if (j0>51) { /* no fraction part */
*iptr = x*one;
u.d = x;
__HI(u) &= 0x80000000;
__LO(u) = 0; /* return +-0 */
x = u.d;
return x;
} else { /* fraction part in low x */
i = ((unsigned)(0xffffffff))>>(j0-20);
if((i1&i)==0) { /* x is integral */
*iptr = x;
u.d = x;
__HI(u) &= 0x80000000;
__LO(u) = 0; /* return +-0 */
x = u.d;
return x;
} else {
u.d = *iptr;
__HI(u) = i0;
__LO(u) = i1&(~i);
*iptr = u.d;
return x - *iptr;
}
}
}