1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
24 */
25 /*
26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
27 * Use is subject to license terms.
28 */
29
30 #pragma weak fmax = __fmax
31
32 /*
33 * fmax(x,y) returns the larger of x and y. If just one of the
34 * arguments is NaN, fmax returns the other argument. If both
35 * arguments are NaN, fmax returns NaN.
36 *
37 * See fmaxf.c for a discussion of implementation trade-offs.
38 */
39
40 #include "libm.h" /* for isgreaterequal macro */
41 #include <fenv.h>
42
43 double
__fmax(double x,double y)44 __fmax(double x, double y) {
45 union {
46 unsigned i[2];
47 double d;
48 } xx, yy;
49 unsigned s;
50
51 /* if y is nan, replace it by x */
52 if (y != y)
53 y = x;
54
55 /* if x is nan, replace it by y */
56 if (x != x)
57 x = y;
58
59 /* At this point, x and y are either both numeric, or both NaN */
60 if (!isnan(x) && !isgreaterequal(x, y))
61 x = y;
62
63 /*
64 * clear the sign of the result if either x or y has its sign clear
65 */
66 xx.d = x;
67 yy.d = y;
68 #if defined(__sparc)
69 s = ~(xx.i[0] & yy.i[0]) & 0x80000000;
70 xx.i[0] &= ~s;
71 #elif defined(__x86)
72 s = ~(xx.i[1] & yy.i[1]) & 0x80000000;
73 xx.i[1] &= ~s;
74 #else
75 #error Unknown architecture
76 #endif
77
78 return (xx.d);
79 }
80