xref: /freebsd/lib/msun/src/s_roundl.c (revision 402cee1f19b613bae844a176156a41cdfa507585)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2003, Steven G. Kargl
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice unmodified, this list of conditions, and the following
12  *    disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <float.h>
33 #ifdef __i386__
34 #include <ieeefp.h>
35 #endif
36 
37 #include "fpmath.h"
38 #include "math.h"
39 #include "math_private.h"
40 
41 long double
42 roundl(long double x)
43 {
44 	long double t;
45 	uint16_t hx;
46 
47 	GET_LDBL_EXPSIGN(hx, x);
48 	if ((hx & 0x7fff) == 0x7fff)
49 		return (x + x);
50 
51 	ENTERI();
52 
53 	if (!(hx & 0x8000)) {
54 		t = floorl(x);
55 		if (t - x <= -0.5L)
56 			t += 1;
57 		RETURNI(t);
58 	} else {
59 		t = floorl(-x);
60 		if (t + x <= -0.5L)
61 			t += 1;
62 		RETURNI(-t);
63 	}
64 }
65