/*
 * $Id: math_rint.c,v 1.5 2006-01-08 12:04:24 obarthel Exp $
 *
 * :ts=4
 *
 * Portable ISO 'C' (1994) runtime library for the Amiga computer
 * Copyright (c) 2002-2015 by Olaf Barthel <obarthel (at) gmx.net>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Neither the name of Olaf Barthel nor the names of contributors
 *     may be used to endorse or promote products derived from this
 *     software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 *
 * PowerPC math library based in part on work by Sun Microsystems
 * 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 _MATH_HEADERS_H
#include "math_headers.h"
#endif /* _MATH_HEADERS_H */

/****************************************************************************/

/* The following is not part of the ISO 'C' (1994) (1994) standard. */

/****************************************************************************/

#if defined(FLOATING_POINT_SUPPORT)

/****************************************************************************/

#if defined(IEEE_FLOATING_POINT_SUPPORT) || defined(M68881_FLOATING_POINT_SUPPORT)

/****************************************************************************/

double
rint(double x)
{
	return floor ( x+0.5 );
}

/****************************************************************************/

#endif /* IEEE_FLOATING_POINT_SUPPORT || M68881_FLOATING_POINT_SUPPORT */

/****************************************************************************/

#if defined(PPC_FLOATING_POINT_SUPPORT)

/****************************************************************************/

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;
	GET_HIGH_WORD(i0,x);
	sx = (i0>>31)&1;
	GET_LOW_WORD(i1,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;
		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 = ((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));
	}
	
	SET_HIGH_WORD(x,i0);
	SET_LOW_WORD(x,i1);
	w = TWO52[sx]+x;
	return w-TWO52[sx];
}

/****************************************************************************/

#endif /* PPC_FLOATING_POINT_SUPPORT */

/****************************************************************************/

#endif /* FLOATING_POINT_SUPPORT */