1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG>
5 * 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 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <float.h>
30#include <math.h>
31
32#include "fpmath.h"
33
34#if LDBL_MAX_EXP != 0x4000
35#error "Unsupported long double format"
36#endif
37
38long double
39frexpl(long double x, int *ex)
40{
41	union IEEEl2bits u;
42
43	u.e = x;
44	switch (u.bits.exp) {
45	case 0:		/* 0 or subnormal */
46		if ((u.bits.manl | u.bits.manh) == 0) {
47			*ex = 0;
48		} else {
49			u.e *= 0x1.0p514;
50			*ex = u.bits.exp - 0x4200;
51			u.bits.exp = 0x3ffe;
52		}
53		break;
54	case 0x7fff:	/* infinity or NaN; value of *ex is unspecified */
55		break;
56	default:	/* normal */
57		*ex = u.bits.exp - 0x3ffe;
58		u.bits.exp = 0x3ffe;
59		break;
60	}
61	return (u.e);
62}
63