xref: /titanic_44/usr/src/lib/libm/common/m9x/fmin.c (revision 0ed5c46e82c989cfa9726d9dae452e3d24ef83be)
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 fmin = __fmin
32 #endif
33 
34 /*
35  * fmin(x,y) returns the smaller of x and y.  If just one of the
36  * arguments is NaN, fmin returns the other argument.  If both
37  * arguments are NaN, fmin returns NaN.
38  *
39  * See fmaxf.c for a discussion of implementation trade-offs.
40  */
41 
42 #include "libm.h"	/* for islessequal macro */
43 
44 #include "fenv_inlines.h"
45 #include <stdio.h>
46 #include <sys/isa_defs.h>
47 
48 double
49 __fmin(double x, double y) {
50 	union {
51 		unsigned i[2];
52 		double d;
53 	} xx, yy;
54 	unsigned s;
55 
56 	/* if y is nan, replace it by x */
57 	if (y != y)
58 		y = x;
59 
60 	/* if x is nan, replace it by y */
61 	if (x != x)
62 		x = y;
63 
64 	/* At this point, x and y are either both numeric, or both NaN */
65 	if (!isnan(x) && !islessequal(x, y))
66 		x = y;
67 
68 	/*
69 	 * set the sign of the result if either x or y has its sign set
70 	 */
71 	xx.d = x;
72 	yy.d = y;
73 #if defined(_BIG_ENDIAN)
74 	s = (xx.i[0] | yy.i[0]) & 0x80000000;
75 	xx.i[0] |= s;
76 #else
77 	s = (xx.i[1] | yy.i[1]) & 0x80000000;
78 	xx.i[1] |= s;
79 #endif
80 
81 	return (xx.d);
82 }
83