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      1 /*  $NetBSD: isinfl.c,v 1.5.16.1 2007/05/07 19:49:07 pavel 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 #include  <LibConfig.h>
     38 #include <sys/EfiCdefs.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 1.5.16.1 2007/05/07 19:49:07 pavel Exp $");
     44 #endif
     45 #endif /* LIBC_SCCS and not lint */
     46 
     47 #include <machine/ieee.h>
     48 #include <math.h>
     49 
     50 #if defined(_MSC_VER)           /* Handle Microsoft VC++ compiler specifics. */
     51   // C4700: uninitialized local variable used
     52   #pragma warning ( disable : 4700 )
     53 #endif
     54 
     55 /*
     56  * 7.12.3.3 isinf - test for infinity
     57  *          IEEE 754 compatible 80-bit extended-precision Intel 386 version
     58  */
     59 int
     60 __isinfl(long double x)
     61 {
     62   union ieee_ext_u u;
     63 
     64   u.extu_ld = x;
     65 
     66   return (u.extu_ext.ext_exp == EXT_EXP_INFNAN &&
     67        u.extu_ext.ext_frach == 0x80000000 && u.extu_ext.ext_fracl == 0);
     68 }
     69