xref: /freebsd/lib/msun/src/s_fmin.c (revision 734e82fe33aa764367791a7d603b383996c6b40b)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 #include <float.h>
31 #include <math.h>
32 
33 #include "fpmath.h"
34 
35 #ifdef USE_BUILTIN_FMIN
36 double
37 fmin(double x, double y)
38 {
39 	return (__builtin_fmin(x, y));
40 }
41 #else
42 double
43 fmin(double x, double y)
44 {
45 	union IEEEd2bits u[2];
46 
47 	u[0].d = x;
48 	u[1].d = y;
49 
50 	/* Check for NaNs to avoid raising spurious exceptions. */
51 	if (u[0].bits.exp == 2047 && (u[0].bits.manh | u[0].bits.manl) != 0)
52 		return (y);
53 	if (u[1].bits.exp == 2047 && (u[1].bits.manh | u[1].bits.manl) != 0)
54 		return (x);
55 
56 	/* Handle comparisons of signed zeroes. */
57 	if (u[0].bits.sign != u[1].bits.sign)
58 		return (u[u[1].bits.sign].d);
59 
60 	return (x < y ? x : y);
61 }
62 #endif
63 
64 #if (LDBL_MANT_DIG == 53)
65 __weak_reference(fmin, fminl);
66 #endif
67