xref: /freebsd/lib/msun/src/s_fmaxf.c (revision f81cdf24ba5436367377f7c8e8f51f6df2a75ca7)
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 <math.h>
30 
31 #include "fpmath.h"
32 
33 #ifdef USE_BUILTIN_FMAXF
34 float
35 fmaxf(float x, float y)
36 {
37 	return (__builtin_fmaxf(x, y));
38 }
39 #else
40 float
41 fmaxf(float x, float y)
42 {
43 	union IEEEf2bits u[2];
44 
45 	u[0].f = x;
46 	u[1].f = y;
47 
48 	/* Check for NaNs to avoid raising spurious exceptions. */
49 	if (u[0].bits.exp == 255 && u[0].bits.man != 0)
50 		return (y);
51 	if (u[1].bits.exp == 255 && u[1].bits.man != 0)
52 		return (x);
53 
54 	/* Handle comparisons of signed zeroes. */
55 	if (u[0].bits.sign != u[1].bits.sign)
56 		return (u[u[0].bits.sign].f);
57 
58 	return (x > y ? x : y);
59 }
60 #endif
61