xref: /titanic_41/usr/src/lib/libm/common/m9x/fdim.c (revision dfa1896db444d8b104da7cb009f39f1a89a438aa)
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 fdim = __fdim
31 
32 /*
33  * fdim(x,y) returns x - y if x > y, +0 if x <= y, and NaN if x and
34  * y are unordered.
35  *
36  * fdim(x,y) raises overflow or inexact if x > y and x - y overflows
37  * or is inexact.  It raises invalid if either operand is a signaling
38  * NaN.  Otherwise, it raises no exceptions.
39  */
40 
41 #include "libm.h"	/* for islessequal macro */
42 
43 double
44 __fdim(double x, double y) {
45 	if (islessequal(x, y)) {
46 		x = 0.0;
47 		y = -x;
48 	}
49 	return (x - y);
50 }
51