1/*	$NetBSD: frexp.c,v 1.4 2003/08/07 16:42:31 agc 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
35static char sccsid[] = "@(#)frexp.c	8.1 (Berkeley) 6/4/93";
36#else
37__RCSID("$NetBSD: frexp.c,v 1.4 2003/08/07 16:42:31 agc Exp $");
38#endif
39#endif /* LIBC_SCCS and not lint */
40
41#include <sys/types.h>
42#include <math.h>
43
44double
45frexp(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