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//===========================================================================

//

//      e_remainder.c

//

//      Part of the standard mathematical function library

//

//===========================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

// This file is part of eCos, the Embedded Configurable Operating System.

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

//

// eCos is free software; you can redistribute it and/or modify it under

// the terms of the GNU General Public License as published by the Free

// Software Foundation; either version 2 or (at your option) any later version.

//

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// WARRANTY; without even the implied warranty of MERCHANTABILITY or

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

// for more details.

//

// You should have received a copy of the GNU General Public License along

// with eCos; if not, write to the Free Software Foundation, Inc.,

// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

//

// As a special exception, if other files instantiate templates or use macros

// or inline functions from this file, or you compile this file and link it

// with other works to produce a work based on this file, this file does not

// by itself cause the resulting work to be covered by the GNU General Public

// License. However the source code for this file must still be made available

// in accordance with section (3) of the GNU General Public License.

//

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// this file might be covered by the GNU General Public License.

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// at http://sources.redhat.com/ecos/ecos-license/

// -------------------------------------------

//####ECOSGPLCOPYRIGHTEND####

//===========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):   jlarmour

// Contributors:  jlarmour

// Date:        1998-02-13

// Purpose:     

// Description: 

// Usage:       

//

//####DESCRIPTIONEND####

//

//===========================================================================

// CONFIGURATION

#include <pkgconf/libm.h>   // Configuration header

// Include the Math library?

#ifdef CYGPKG_LIBM     

// Derived from code with the following copyright

/* @(#)e_remainder.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.

 * ====================================================

 */

/* __ieee754_remainder(x,p)

 * Return :

 *      returns  x REM p  =  x - [x/p]*p as if in infinite

 *      precise arithmetic, where [x/p] is the (infinite bit)

 *      integer nearest x/p (in half way case choose the even one).

 * Method :

 *      Based on fmod() return x-[x/p]chopped*p exactlp.

 */

#include "mathincl/fdlibm.h"

static const double zero = 0.0;

        double __ieee754_remainder(double x, double p)

{

        int hx,hp;

        unsigned sx,lx,lp;

        double p_half;

        hx = CYG_LIBM_HI(x);            /* high word of x */

        lx = CYG_LIBM_LO(x);            /* low  word of x */

        hp = CYG_LIBM_HI(p);            /* high word of p */

        lp = CYG_LIBM_LO(p);            /* low  word of p */

        sx = hx&0x80000000;

        hp &= 0x7fffffff;

        hx &= 0x7fffffff;

    /* purge off exception values */

        if((hp|lp)==0) return (x*p)/(x*p);      /* p = 0 */

        if((hx>=0x7ff00000)||                   /* x not finite */

          ((hp>=0x7ff00000)&&                   /* p is NaN */

          (((hp-0x7ff00000)|lp)!=0)))

            return (x*p)/(x*p);

        if (hp<=0x7fdfffff) x = __ieee754_fmod(x,p+p);  /* now x < 2p */

        if (((hx-hp)|(lx-lp))==0) return zero*x;

        x  = fabs(x);

        p  = fabs(p);

        if (hp<0x00200000) {

            if(x+x>p) {

                x-=p;

                if(x+x>=p) x -= p;

            }

        } else {

            p_half = 0.5*p;

            if(x>p_half) {

                x-=p;

                if(x>=p_half) x -= p;

            }

        }

        CYG_LIBM_HI(x) ^= sx;

        return x;

}

#endif // ifdef CYGPKG_LIBM     

// EOF e_remainder.c