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
34double
35scalb(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