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 __lrint = lrint
31
32 /*
33 * lrint(x) rounds its argument to the nearest integer according
34 * to the current rounding direction and converts the result to
35 * a 32 bit signed integer.
36 *
37 * If x is NaN, infinite, or so large that the nearest integer
38 * would exceed 32 bits, the invalid operation exception is raised.
39 * If x is not an integer, the inexact exception is raised.
40 */
41
42 #include <sys/isa_defs.h> /* _ILP32 */
43 #include "libm.h"
44
45 #if defined(_ILP32)
46 long
lrint(double x)47 lrint(double x) {
48 /*
49 * Note: The following code works on x86 (in the default rounding
50 * precision mode), but one should just use the fistpl instruction
51 * instead.
52 */
53 union {
54 unsigned i[2];
55 double d;
56 } xx, yy;
57 unsigned hx;
58
59 xx.d = x;
60 hx = xx.i[HIWORD] & ~0x80000000;
61 if (hx < 0x43300000) { /* |x| < 2^52 */
62 /* add and subtract a power of two to round x to an integer */
63 #if defined(__sparc)
64 yy.i[HIWORD] = (xx.i[HIWORD] & 0x80000000) | 0x43300000;
65 #elif defined(__x86)
66 yy.i[HIWORD] = (xx.i[HIWORD] & 0x80000000) | 0x43e00000;
67 #else
68 #error Unknown architecture
69 #endif
70 yy.i[LOWORD] = 0;
71 x = (x + yy.d) - yy.d;
72 }
73
74 /* now x is nan, inf, or integral */
75 return ((long) x);
76 }
77 #else
78 #error Unsupported architecture
79 #endif /* defined(_ILP32) */
80