/*--------------------------------------------------------------------

 *© Portions copyright (c) 2006 Nokia Corporation.  All rights reserved.

 *--------------------------------------------------------------------

*/

/* @(#)s_rint.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.

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

 */

#ifndef __SYMBIAN32__

#ifndef lint

static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_rint.c,v 1.11 2005/03/07 20:28:26 stefanf Exp $";

#endif

#endif //__SYMBIAN32__

/*

 * 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 <math.h>

#include "math_private.h"

/*

 * TWO23 is long double instead of double to avoid a bug in gcc.  Without

 * this, gcc thinks that TWO23[sx]+x and w-TWO23[sx] already have double

 * precision and doesn't clip them to double precision when they are

 * assigned and returned.

 */

static const long double

TWO52[2]={

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

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

};

EXPORT_C double rint(double x)

{

	int32_t i0,j0,sx;

	u_int32_t i,i1;

	double w,t;

	EXTRACT_WORDS(i0,i1,x);

	sx = (i0>>31)&1;

	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;

		SET_HIGH_WORD(x,i0);

	        w = TWO52[sx]+x;

	        t =  w-TWO52[sx];

		GET_HIGH_WORD(i0,t);

		SET_HIGH_WORD(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 = ((u_int32_t)(0xffffffff))>>(j0-20);

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

	    i>>=1;

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

	}

	INSERT_WORDS(x,i0,i1);

	w = TWO52[sx]+x;

	return w-TWO52[sx];

}