xref: /titanic_41/usr/src/lib/libm/common/m9x/fmaxl.c (revision ef26a926e54f934431066685d069cbf73bba1534)
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 #if defined(ELFOBJ)
31 #pragma weak fmaxl = __fmaxl
32 #endif
33 
34 #include "libm.h"	/* for isgreaterequal macro */
35 
36 long double
37 __fmaxl(long double x, long double y) {
38 	union {
39 #if defined(__sparc)
40 		unsigned i[4];
41 #elif defined(__x86)
42 		unsigned i[3];
43 #else
44 #error Unknown architecture
45 #endif
46 		long double ld;
47 	} xx, yy;
48 	unsigned s;
49 
50 	/* if y is nan, replace it by x */
51 	if (y != y)
52 		y = x;
53 
54 	/* if x is nan, replace it by y */
55 	if (x != x)
56 		x = y;
57 
58 	/* At this point, x and y are either both numeric, or both NaN */
59 	if (!isnan(x) && !isgreaterequal(x, y))
60 		x = y;
61 
62 	/*
63 	 * clear the sign of the result if either x or y has its sign clear
64 	 */
65 	xx.ld = x;
66 	yy.ld = y;
67 #if defined(__sparc)
68 	s = ~(xx.i[0] & yy.i[0]) & 0x80000000;
69 	xx.i[0] &= ~s;
70 #elif defined(__x86)
71 	s = ~(xx.i[2] & yy.i[2]) & 0x8000;
72 	xx.i[2] &= ~s;
73 #else
74 #error Unknown architecture
75 #endif
76 
77 	return (xx.ld);
78 }
79