xref: /netbsd-src/lib/libm/src/s_fmaxl.c (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /*-
2  * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __RCSID("$NetBSD: s_fmaxl.c,v 1.2 2010/03/08 01:05:20 snj Exp $");
29 #ifdef notdef
30 __FBSDID("$FreeBSD: src/lib/msun/src/s_fmaxl.c,v 1.1 2004/06/30 07:04:01 das Exp $");
31 #endif
32 
33 #include <math.h>
34 
35 #include <machine/ieee.h>
36 #ifdef EXT_EXP_INFNAN
37 long double
38 fmaxl(long double x, long double y)
39 {
40 	union ieee_ext_u u[2];
41 
42 	u[0].extu_ld = x;
43 	u[0].extu_ext.ext_frach &= ~0x80000000;
44 	u[1].extu_ld = y;
45 	u[1].extu_ext.ext_frach &= ~0x80000000;
46 
47 	/* Check for NaNs to avoid raising spurious exceptions. */
48 	if (u[0].extu_ext.ext_exp == EXT_EXP_INFNAN &&
49 	    (u[0].extu_ext.ext_frach | u[0].extu_ext.ext_fracl) != 0)
50 		return (y);
51 	if (u[1].extu_ext.ext_exp == EXT_EXP_INFNAN &&
52 	    (u[1].extu_ext.ext_frach | u[1].extu_ext.ext_fracl) != 0)
53 		return (x);
54 
55 	/* Handle comparisons of ext_signed zeroes. */
56 	if (u[0].extu_ext.ext_sign != u[1].extu_ext.ext_sign)
57 		return (u[0].extu_ext.ext_sign ? y : x);
58 
59 	return (x > y ? x : y);
60 }
61 #endif
62