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
47 long long
llround(double x)48 llround(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