xref: /dflybsd-src/contrib/openbsd_libm/src/s_roundl.c (revision 6b6b4dd0d75b9cd8fd4deebd4046aae2f1fafb10)

/*	$OpenBSD: s_roundl.c,v 1.2 2012/12/05 23:20:04 deraadt Exp $	*/

/*-
 * Copyright (c) 2003, Steven G. Kargl
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions, and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

#include <math.h>
#include "math_private.h"

long double
roundl(long double x)
{
	long double t;
	uint16_t hx;

	GET_LDOUBLE_EXP(hx, x);
	if ((hx & 0x7fff) == 0x7fff)
		return (x + x);


	if (!(hx & 0x8000)) {
		t = floorl(x);
		if (t - x <= -0.5L)
			t += 1;
		return (t);
	} else {
		t = floorl(-x);
		if (t + x <= -0.5L)
			t += 1;
		return (-t);
	}
}