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 __llrint = llrint
31 #if defined(__sparcv9) || defined(__amd64)
32 #pragma weak lrint = llrint
33 #pragma weak __lrint = llrint
34 #endif
35
36 /*
37 * llrint(x) rounds its argument to the nearest integer according
38 * to the current rounding direction and converts the result to a
39 * 64 bit signed integer.
40 *
41 * If x is NaN, infinite, or so large that the nearest integer would
42 * exceed 64 bits, the invalid operation exception is raised. If x
43 * is not an integer, the inexact exception is raised.
44 */
45
46 #include "libm.h"
47
48 long long
llrint(double x)49 llrint(double x) {
50 /*
51 * Note: The following code works on x86 (in the default rounding
52 * precision mode), but one should just use the fistpll instruction
53 * instead.
54 */
55 union {
56 unsigned i[2];
57 double d;
58 } xx, yy;
59 unsigned hx;
60
61 xx.d = x;
62 hx = xx.i[HIWORD] & ~0x80000000;
63
64 if (hx < 0x43300000) { /* |x| < 2^52 */
65 /* add and subtract a power of two to round x to an integer */
66 #if defined(__sparc) || defined(__amd64)
67 yy.i[HIWORD] = (xx.i[HIWORD] & 0x80000000) | 0x43300000;
68 #elif defined(__i386) /* !defined(__amd64) */
69 yy.i[HIWORD] = (xx.i[HIWORD] & 0x80000000) | 0x43e00000;
70 #else
71 #error Unknown architecture
72 #endif
73 yy.i[LOWORD] = 0;
74 x = (x + yy.d) - yy.d;
75 }
76
77 /* now x is nan, inf, or integral */
78 return ((long long) x);
79 }
80