1 /*-
2 * Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
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
38 long double
frexpl(long double x,int * ex)39 frexpl(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