1 /* $NetBSD: frexp.c,v 1.5 2012/06/25 22:32:43 abs Exp $ */
2
3 /*-
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static char sccsid[] = "@(#)frexp.c 8.1 (Berkeley) 6/4/93";
36 #else
37 __RCSID("$NetBSD: frexp.c,v 1.5 2012/06/25 22:32:43 abs Exp $");
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40
41 #include <sys/types.h>
42 #include <math.h>
43
44 double
frexp(double value,int * eptr)45 frexp(double value, int *eptr)
46 {
47 union {
48 double v;
49 struct {
50 u_int u_mant1 : 7;
51 u_int u_exp : 8;
52 u_int u_sign : 1;
53 u_int u_mant2 : 16;
54 u_int u_mant3 : 32;
55 } s;
56 } u;
57
58 if (value) {
59 u.v = value;
60 *eptr = u.s.u_exp - 128;
61 u.s.u_exp = 128;
62 return (u.v);
63 } else {
64 *eptr = 0;
65 return (0.0);
66 }
67 }
68