1 /*-
2 * Copyright (c) 2003, Steven G. Kargl
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
10 * disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29
30 #include <float.h>
31
32 #include "math.h"
33 #include "math_private.h"
34
35 double
round(double x)36 round(double x)
37 {
38 double t;
39 uint32_t hx;
40
41 GET_HIGH_WORD(hx, x);
42 if ((hx & 0x7fffffff) == 0x7ff00000)
43 return (x + x);
44
45 if (!(hx & 0x80000000)) {
46 t = floor(x);
47 if (t - x <= -0.5)
48 t += 1;
49 return (t);
50 } else {
51 t = floor(-x);
52 if (t + x <= -0.5)
53 t += 1;
54 return (-t);
55 }
56 }
57
58 #if SUPPORT_LONG_DOUBLE
59 #if (LDBL_MANT_DIG == 53)
60 __weak_reference(round, roundl);
61 #endif
62 #endif
63