1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
23 */
24 /*
25 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
26 * Use is subject to license terms.
27 */
28
29 #pragma weak __scalb = scalb
30 #pragma weak _scalb = scalb
31
32 #include "libm.h"
33
34 double
scalb(double x,double fn)35 scalb(double x, double fn) {
36 int hn, in, n;
37 double z;
38
39 if (isnan(x) || isnan(fn))
40 return (x * fn);
41
42 in = ((int *)&fn)[HIWORD];
43 hn = in & ~0x80000000;
44 if (hn == 0x7ff00000) /* fn is inf */
45 return (_SVID_libm_err(x, fn, 47));
46
47 /* see if fn is an integer without raising inexact */
48 if (hn >= 0x43300000) {
49 /* |fn| >= 2^52, so it must be an integer */
50 n = (in < 0)? -65000 : 65000;
51 } else if (hn < 0x3ff00000) {
52 /* |fn| < 1, so it must be zero or non-integer */
53 return ((fn == 0.0)? x : (x - x) / (x - x));
54 } else if (hn < 0x41400000) {
55 /* |fn| < 2^21 */
56 if ((hn & ((1 << (0x413 - (hn >> 20))) - 1))
57 | ((int *)&fn)[LOWORD])
58 return ((x - x) / (x - x));
59 n = (int)fn;
60 } else {
61 if (((int *)&fn)[LOWORD] & ((1 << (0x433 - (hn >> 20))) - 1))
62 return ((x - x) / (x - x));
63 n = (in < 0)? -65000 : 65000;
64 }
65 z = scalbn(x, n);
66 if (z != x) {
67 if (z == 0.0)
68 return (_SVID_libm_err(x, fn, 33));
69 if (!finite(z))
70 return (_SVID_libm_err(x, fn, 32));
71 }
72 return (z);
73 }
74