xref: /freebsd/lib/msun/src/s_fmaxl.c (revision 2f02600abfddfc4e9f20dd384a2e729b451e16bd)
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 __FBSDID("$FreeBSD$");
29 
30 #include <math.h>
31 
32 #include "fpmath.h"
33 
34 long double
35 fmaxl(long double x, long double y)
36 {
37 	union IEEEl2bits u[2];
38 
39 	u[0].e = x;
40 	mask_nbit_l(u[0]);
41 	u[1].e = y;
42 	mask_nbit_l(u[1]);
43 
44 	/* Check for NaNs to avoid raising spurious exceptions. */
45 	if (u[0].bits.exp == 32767 && (u[0].bits.manh | u[0].bits.manl) != 0)
46 		return (y);
47 	if (u[1].bits.exp == 32767 && (u[1].bits.manh | u[1].bits.manl) != 0)
48 		return (x);
49 
50 	/* Handle comparisons of signed zeroes. */
51 	if (u[0].bits.sign != u[1].bits.sign)
52 		return (u[0].bits.sign ? y : x);
53 
54 	return (x > y ? x : y);
55 }
56