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 /*
23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
24 */
25 /*
26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
27 * Use is subject to license terms.
28 */
29
30 #pragma weak __rintl = rintl
31
32 /*
33 * rintl(long double x) return x rounded to integral according to
34 * the prevailing rounding direction
35 *
36 * NOTE: aintl(x), anintl(x), ceill(x), floorl(x), and rintl(x) return result
37 * with the same sign as x's, including 0.0L.
38 */
39
40 #include "libm.h"
41 #include "longdouble.h"
42
43 extern enum fp_precision_type __swapRP(enum fp_precision_type);
44
45 static const double one = 1.0;
46 static const long double qzero = 0.0L;
47
48 long double
rintl(long double x)49 rintl(long double x) {
50 enum fp_precision_type rp;
51 long double t, w, two112;
52 int *pt = (int *) &two112;
53
54 if (!finitel(x))
55 return (x + x);
56
57 if (*(int *) &one != 0) { /* set two112 = 2^112 */
58 pt[0] = 0x406f0000;
59 pt[1] = pt[2] = pt[3] = 0;
60 } else {
61 pt[3] = 0x406f0000;
62 pt[0] = pt[1] = pt[2] = 0;
63 }
64
65 if (fabsl(x) >= two112)
66 return (x); /* already an integer */
67 t = copysignl(two112, x);
68 rp = __swapRP(fp_extended); /* make sure precision is long double */
69 w = x + t; /* x+sign(x)*2^112 rounded to integer */
70 (void) __swapRP(rp); /* restore precision mode */
71 if (w == t)
72 return (copysignl(qzero, x)); /* x rounded to zero */
73 else
74 return (w - t);
75 }
76