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 __roundf = roundf
31
32#include "libm.h"
33
34float
35roundf(float x) {
36	union {
37		unsigned i;
38		float f;
39	} xx;
40	unsigned hx, sx, i;
41
42	xx.f = x;
43	hx = xx.i & ~0x80000000;
44	sx = xx.i & 0x80000000;
45	if (hx < 0x4b000000) {		/* |x| < 2^23 */
46		if (hx < 0x3f800000) {		/* |x| < 1 */
47			if (hx >= 0x3f000000)
48				return (sx ? -1.0F : 1.0F);
49			return (sx ? -0.0F : 0.0F);
50		}
51
52		/* round x at the integer bit */
53		i = 1 << (0x95 - (hx >> 23));
54		xx.i = (xx.i + i) & ~((i << 1) - 1);
55		return (xx.f);
56	} else if (hx < 0x7f800000)	/* |x| is integral */
57		return (x);
58	else
59#if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN)
60		return (hx > 0x7f800000 ? x * x : x + x);
61#else
62		return (x + x);
63#endif
64}
65