xref: /minix3/lib/libc/arch/i386/gen/isnanl.c (revision f14fb602092e015ff630df58e17c2a9cd57d29b3)

/*	$NetBSD: isnanl.c,v 1.8 2011/06/05 14:43:13 christos Exp $	*/

/*
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This software was developed by the Computer Systems Engineering group
 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
 * contributed to Berkeley.
 *
 * 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, 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 * from: Header: isinf.c,v 1.1 91/07/08 19:03:34 torek Exp
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)isinf.c	8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: isnanl.c,v 1.8 2011/06/05 14:43:13 christos Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#include <machine/ieee.h>
#include <math.h>

/*
 * 7.12.3.4 isnan - test for a NaN
 *          IEEE 754 compatible 80-bit extended-precision Intel 386 version
 */
int
__isnanl(long double x)
{
	union ieee_ext_u u;

	u.extu_ld = x;

	return (u.extu_ext.ext_exp == EXT_EXP_INFNAN &&
	    (u.extu_ext.ext_frach & 0x80000000) != 0 &&
	    (u.extu_ext.ext_frach != 0x80000000 || u.extu_ext.ext_fracl != 0));
}