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 __lround = lround
31
32 /*
33 * lround(x) rounds its argument to the nearest integer, rounding ties
34 * away from zero, and converts the result to a 32 bit signed integer.
35 *
36 * If x is NaN, infinite, or so large that the nearest integer
37 * would exceed 32 bits, the invalid operation exception is raised.
38 */
39
40 #include <sys/isa_defs.h> /* _ILP32 */
41 #include "libm.h"
42
43 #if defined(_ILP32)
44 long
lround(double x)45 lround(double x) {
46 union {
47 unsigned i[2];
48 double d;
49 } xx;
50 unsigned hx, sx, i;
51
52 xx.d = x;
53 hx = xx.i[HIWORD] & ~0x80000000;
54 sx = xx.i[HIWORD] & 0x80000000;
55 if (hx < 0x43300000) { /* |x| < 2^52 */
56 if (hx < 0x3ff00000) { /* |x| < 1 */
57 if (hx >= 0x3fe00000)
58 return (sx ? -1L : 1L);
59 return (0L);
60 }
61
62 /* round x at the integer bit */
63 if (hx < 0x41300000) {
64 i = 1 << (0x412 - (hx >> 20));
65 xx.i[HIWORD] = (xx.i[HIWORD] + i) & ~(i | (i - 1));
66 xx.i[LOWORD] = 0;
67 } else {
68 i = 1 << (0x432 - (hx >> 20));
69 xx.i[LOWORD] += i;
70 if (xx.i[LOWORD] < i)
71 xx.i[HIWORD]++;
72 xx.i[LOWORD] &= ~(i | (i - 1));
73 }
74 }
75
76 /* now x is nan, inf, or integral */
77 return ((long) xx.d);
78 }
79 #else
80 #error Unsupported architecture
81 #endif /* defined(_ILP32) */
82