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isinfl.c revision 1.2 
      1 /*	$NetBSD: isinfl.c,v 1.2 2003/10/27 00:05:46 kleink Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1992, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This software was developed by the Computer Systems Engineering group
      8  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
      9  * contributed to Berkeley.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  * 3. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  *
     35  * from: Header: isinf.c,v 1.1 91/07/08 19:03:34 torek Exp
     36  */
     37 
     38 #include <sys/cdefs.h>
     39 #if defined(LIBC_SCCS) && !defined(lint)
     40 #if 0
     41 static char sccsid[] = "@(#)isinf.c	8.1 (Berkeley) 6/4/93";
     42 #else
     43 __RCSID("$NetBSD: isinfl.c,v 1.2 2003/10/27 00:05:46 kleink Exp $");
     44 #endif
     45 #endif /* LIBC_SCCS and not lint */
     46 
     47 #include "namespace.h"
     48 #include <sys/types.h>
     49 #include <machine/ieee.h>
     50 #include <math.h>
     51 
     52 #if 0	/* XXX Currently limited to internal use. */
     53 #ifdef __weak_alias
     54 __weak_alias(isinfl,_isinfl)
     55 #endif
     56 #endif
     57 
     58 int
     59 isinfl(long double ld)
     60 {
     61 	union ieee_ext_u u;
     62 
     63 	u.extu_ld = ld;
     64 	/* Note: the explicit integer bit is "don't care". */
     65 	return (u.extu_ldbl.ext_exp == EXT_EXP_INFNAN &&
     66 	    (u.extu_ldbl.ext_frach == 0 && u.extu_ldbl.ext_fracl == 0));
     67 }
     68