xref: /minix3/lib/libm/src/s_frexpl.c (revision 84d9c625bfea59e274550651111ae9edfdc40fbd)
1 /*	$NetBSD: s_frexpl.c,v 1.3 2013/02/12 21:40:19 martin Exp $	*/
2 
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  * $FreeBSD: src/lib/msun/src/s_frexpl.c,v 1.1 2005/03/07 04:54:51 das Exp $
29  */
30 
31 #include <sys/cdefs.h>
32 __RCSID("$NetBSD: s_frexpl.c,v 1.3 2013/02/12 21:40:19 martin Exp $");
33 
34 #include <machine/ieee.h>
35 #include <float.h>
36 #include <math.h>
37 
38 #include "math_private.h"
39 
40 #ifdef __HAVE_LONG_DOUBLE
41 #if LDBL_MAX_EXP != 0x4000
42 #error "Unsupported long double format"
43 #endif
44 
45 long double
frexpl(long double x,int * ex)46 frexpl(long double x, int *ex)
47 {
48 	union ieee_ext_u u;
49 
50 	u.extu_ld = x;
51 	switch (u.extu_ext.ext_exp) {
52 	case 0:		/* 0 or subnormal */
53 		if ((u.extu_ext.ext_fracl | u.extu_ext.ext_frach) == 0) {
54 			*ex = 0;
55 		} else {
56 			u.extu_ld *= 0x1.0p514;
57 			*ex = u.extu_ext.ext_exp - 0x4200;
58 			u.extu_ext.ext_exp = 0x3ffe;
59 		}
60 		break;
61 	case 0x7fff:	/* infinity or NaN; value of *ex is unspecified */
62 		break;
63 	default:	/* normal */
64 		*ex = u.extu_ext.ext_exp - 0x3ffe;
65 		u.extu_ext.ext_exp = 0x3ffe;
66 		break;
67 	}
68 	return (u.extu_ld);
69 }
70 #endif
71