1be0c75e8SJohn Marino /* $OpenBSD: frexp.c,v 1.10 2013/07/03 04:46:36 espie Exp $ */
2be0c75e8SJohn Marino
3be0c75e8SJohn Marino /*-
4be0c75e8SJohn Marino * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
5be0c75e8SJohn Marino * All rights reserved.
6be0c75e8SJohn Marino *
7be0c75e8SJohn Marino * Redistribution and use in source and binary forms, with or without
8be0c75e8SJohn Marino * modification, are permitted provided that the following conditions
9be0c75e8SJohn Marino * are met:
10be0c75e8SJohn Marino * 1. Redistributions of source code must retain the above copyright
11be0c75e8SJohn Marino * notice, this list of conditions and the following disclaimer.
12be0c75e8SJohn Marino * 2. Redistributions in binary form must reproduce the above copyright
13be0c75e8SJohn Marino * notice, this list of conditions and the following disclaimer in the
14be0c75e8SJohn Marino * documentation and/or other materials provided with the distribution.
15be0c75e8SJohn Marino *
16be0c75e8SJohn Marino * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17be0c75e8SJohn Marino * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18be0c75e8SJohn Marino * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19be0c75e8SJohn Marino * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20be0c75e8SJohn Marino * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21be0c75e8SJohn Marino * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22be0c75e8SJohn Marino * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23be0c75e8SJohn Marino * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24be0c75e8SJohn Marino * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25be0c75e8SJohn Marino * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26be0c75e8SJohn Marino * SUCH DAMAGE.
27be0c75e8SJohn Marino *
28be0c75e8SJohn Marino * $FreeBSD: frexp.c,v 1.1 2004/07/18 21:23:39 das Exp $
29be0c75e8SJohn Marino */
30be0c75e8SJohn Marino
31be0c75e8SJohn Marino #include <sys/types.h>
32be0c75e8SJohn Marino #include <machine/ieee.h>
33be0c75e8SJohn Marino #include <float.h>
34be0c75e8SJohn Marino #include <math.h>
35be0c75e8SJohn Marino
36be0c75e8SJohn Marino #pragma GCC diagnostic push
37be0c75e8SJohn Marino #pragma GCC diagnostic ignored "-Wmissing-prototypes"
38be0c75e8SJohn Marino
39*404c8a26SSascha Wildner __sym_compat(frexp, past_frexp, DF306.0);
40be0c75e8SJohn Marino double
past_frexp(double v,int * ex)41*404c8a26SSascha Wildner past_frexp(double v, int *ex)
42be0c75e8SJohn Marino {
43be0c75e8SJohn Marino union {
44be0c75e8SJohn Marino double v;
45be0c75e8SJohn Marino struct ieee_double s;
46be0c75e8SJohn Marino } u;
47be0c75e8SJohn Marino
48be0c75e8SJohn Marino u.v = v;
49be0c75e8SJohn Marino switch (u.s.dbl_exp) {
50be0c75e8SJohn Marino case 0: /* 0 or subnormal */
51be0c75e8SJohn Marino if ((u.s.dbl_fracl | u.s.dbl_frach) == 0) {
52be0c75e8SJohn Marino *ex = 0;
53be0c75e8SJohn Marino } else {
54be0c75e8SJohn Marino /*
55be0c75e8SJohn Marino * The power of 2 is arbitrary, any value from 54 to
56be0c75e8SJohn Marino * 1024 will do.
57be0c75e8SJohn Marino */
58be0c75e8SJohn Marino u.v *= 0x1.0p514;
59be0c75e8SJohn Marino *ex = u.s.dbl_exp - (DBL_EXP_BIAS - 1 + 514);
60be0c75e8SJohn Marino u.s.dbl_exp = DBL_EXP_BIAS - 1;
61be0c75e8SJohn Marino }
62be0c75e8SJohn Marino break;
63be0c75e8SJohn Marino case DBL_EXP_INFNAN: /* Inf or NaN; value of *ex is unspecified */
64be0c75e8SJohn Marino break;
65be0c75e8SJohn Marino default: /* normal */
66be0c75e8SJohn Marino *ex = u.s.dbl_exp - (DBL_EXP_BIAS - 1);
67be0c75e8SJohn Marino u.s.dbl_exp = DBL_EXP_BIAS - 1;
68be0c75e8SJohn Marino break;
69be0c75e8SJohn Marino }
70be0c75e8SJohn Marino return (u.v);
71be0c75e8SJohn Marino }
72be0c75e8SJohn Marino
73be0c75e8SJohn Marino #pragma GCC diagnostic pop
74