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)
44long
45lround(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