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

//

//      s_rint.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.

//

// This exception does not invalidate any other reasons why a work based on

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

//

// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.

// 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

/* @(#)s_rint.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.

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

 */

/*

 * rint(x)

 * Return x rounded to integral value according to the prevailing

 * rounding mode.

 * Method:

 *      Using floating addition.

 * Exception:

 *      Inexact flag raised if x not equal to rint(x).

 */

#include "mathincl/fdlibm.h"

static const double

TWO52[2]={

  4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */

 -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */

};

        double rint(double x)

{

        int i0,j0,sx;

        unsigned i,i1;

        double w,t;

        i0 =  CYG_LIBM_HI(x);

        sx = (i0>>31)&1;

        i1 =  CYG_LIBM_LO(x);

        j0 = ((i0>>20)&0x7ff)-0x3ff;

        if(j0<20) {

            if(j0<0) {

                if(((i0&0x7fffffff)|i1)==0) return x;

                i1 |= (i0&0x0fffff);

                i0 &= 0xfffe0000;

                i0 |= ((i1|-i1)>>12)&0x80000;

                CYG_LIBM_HI(x)=i0;

                w = TWO52[sx]+x;

                t =  w-TWO52[sx];

                i0 = CYG_LIBM_HI(t);

                CYG_LIBM_HI(t) = (i0&0x7fffffff)|(sx<<31);

                return t;

            } else {

                i = (0x000fffff)>>j0;

                if(((i0&i)|i1)==0) return x; /* x is integral */

                i>>=1;

                if(((i0&i)|i1)!=0) {

                    if(j0==19) i1 = 0x40000000; else

                    i0 = (i0&(~i))|((0x20000)>>j0);

                }

            }

        } else if (j0>51) {

            if(j0==0x400) return x+x;   /* inf or NaN */

            else return x;              /* x is integral */

        } else {

            i = ((unsigned)(0xffffffff))>>(j0-20);

            if((i1&i)==0) return x;     /* x is integral */

            i>>=1;

            if((i1&i)!=0) i1 = (i1&(~i))|((0x40000000)>>(j0-20));

        }

        CYG_LIBM_HI(x) = i0;

        CYG_LIBM_LO(x) = i1;

        w = TWO52[sx]+x;

        return w-TWO52[sx];

}

#endif // ifdef CYGPKG_LIBM     

// EOF s_rint.c