xref: /illumos-gate/usr/src/lib/libc/sparcv9/fp/__dtoul.c (revision ddb365bfc9e868ad24ccdcb0dc91af18b10df082)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright (c) 1994-1997, by Sun Microsystems, Inc.
24  * All rights reserved.
25  */
26 
27 /*
28  * __dtoul(x) converts double x to unsigned long.
29  */
30 unsigned long
31 __dtoul(double x)
32 {
33 	union {
34 		double		d;
35 		unsigned long	l;
36 	} u;
37 
38 	u.d = x;
39 
40 	/* handle cases for which double->unsigned long differs from */
41 	/* double->signed long */
42 	if ((u.l >> 52) == 0x43e) {
43 		/* 2^63 <= x < 2^64 */
44 		return (0x8000000000000000ul | (u.l << 11));
45 	}
46 
47 	/* for all other cases, just convert to signed long */
48 	return ((long)x);
49 }
50