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_FMAXIMUM_MAG
35 double
fmaximum_mag(double x,double y)36 fmaximum_mag(double x, double y)
37 {
38 return (__builtin_fmaximum_mag(x, y));
39 }
40 #else
41 double
fmaximum_mag(double x,double y)42 fmaximum_mag(double x, double y)
43 {
44 union IEEEd2bits u[2];
45
46 u[0].d = x;
47 u[1].d = y;
48
49 /* Handle NaN according to ISO/IEC 60559. NaN argument -> NaN return */
50 if ((u[0].bits.exp == 2047 && (u[0].bits.manh | u[0].bits.manl) != 0) ||
51 (u[1].bits.exp == 2047 && (u[1].bits.manh | u[1].bits.manl) != 0))
52 return (NAN);
53
54 double ax = fabs(x);
55 double ay = fabs(y);
56
57 if (ay > ax)
58 return (y);
59 if (ax > ay)
60 return (x);
61
62 /* If magnitudes are equal, we break the tie with the sign */
63 if (u[0].bits.sign != u[1].bits.sign)
64 return (u[u[0].bits.sign].d);
65
66 return (x);
67 }
68 #endif
69
70 #if (LDBL_MANT_DIG == 53)
71 __weak_reference(fmaximum_mag, fmaximum_magl);
72 #endif
73
74