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 __llround = llround
31#if defined(__sparcv9) || defined(__amd64)
32#pragma weak lround = llround
33#pragma weak __lround = llround
34#endif
35
36/*
37 * llround(x) rounds its argument to the nearest integer, rounding
38 * ties away from zero, and converts the result to a 64 bit signed
39 * integer.
40 *
41 * If x is NaN, infinite, or so large that the nearest integer
42 * would exceed 64 bits, the invalid operation exception is raised.
43 */
44
45#include "libm.h"
46
47long long
48llround(double x) {
49	union {
50		unsigned i[2];
51		double d;
52	} xx;
53	unsigned hx, sx, i;
54
55	xx.d = x;
56	hx = xx.i[HIWORD] & ~0x80000000;
57	sx = xx.i[HIWORD] & 0x80000000;
58
59	if (hx < 0x43300000) { /* |x| < 2^52 */
60		/* handle |x| < 1 */
61		if (hx < 0x3ff00000) {
62			if (hx >= 0x3fe00000)
63				return (sx ? -1LL : 1LL);
64			return (0LL);
65		}
66
67		/* round x at the integer bit */
68		if (hx < 0x41300000) {
69			i = 1 << (0x412 - (hx >> 20));
70			xx.i[HIWORD] = (xx.i[HIWORD] + i) & ~(i | (i - 1));
71			xx.i[LOWORD] = 0;
72		} else {
73			i = 1 << (0x432 - (hx >> 20));
74			xx.i[LOWORD] += i;
75			if (xx.i[LOWORD] < i)
76				xx.i[HIWORD]++;
77			xx.i[LOWORD] &= ~(i | (i - 1));
78		}
79	}
80
81	/* now x is nan, inf, or integral */
82	return ((long long) xx.d);
83}
84