xref: /openbsd/lib/libm/src/s_fdim.c (revision 404b540a)
1 /*	$OpenBSD: s_fdim.c,v 1.3 2008/12/10 01:08:24 martynas Exp $	*/
2 /*-
3  * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include <sys/cdefs.h>
29 #include <float.h>
30 #include <math.h>
31 
32 #define	DECL(type, fn)			\
33 type					\
34 fn(type x, type y)			\
35 {					\
36 					\
37 	if (isnan(x))			\
38 		return (x);		\
39 	if (isnan(y))			\
40 		return (y);		\
41 	return (x > y ? x - y : 0.0);	\
42 }
43 
44 DECL(double, fdim)
45 DECL(float, fdimf)
46 
47 #if LDBL_MANT_DIG == 53
48 #ifdef __weak_alias
49 __weak_alias(fdiml, fdim);
50 #endif /* __weak_alias */
51 #endif /* LDBL_MANT_DIG == 53 */
52