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 <float.h>
30#include <math.h>
31
32#include "fpmath.h"
33
34#ifdef USE_BUILTIN_FMAX
35double
36fmax(double x, double y)
37{
38	return (__builtin_fmax(x, y));
39}
40#else
41double
42fmax(double x, double y)
43{
44	union IEEEd2bits u[2];
45
46	u[0].d = x;
47	u[1].d = y;
48
49	/* Check for NaNs to avoid raising spurious exceptions. */
50	if (u[0].bits.exp == 2047 && (u[0].bits.manh | u[0].bits.manl) != 0)
51		return (y);
52	if (u[1].bits.exp == 2047 && (u[1].bits.manh | u[1].bits.manl) != 0)
53		return (x);
54
55	/* Handle comparisons of signed zeroes. */
56	if (u[0].bits.sign != u[1].bits.sign)
57		return (u[u[0].bits.sign].d);
58
59	return (x > y ? x : y);
60}
61#endif
62
63#if (LDBL_MANT_DIG == 53)
64__weak_reference(fmax, fmaxl);
65#endif
66