xref: /freebsd/lib/msun/src/s_roundl.c (revision 1843dfb05ed80149f5a412180af882e3cb8f451b)
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 #include <float.h>
31 #ifdef __i386__
32 #include <ieeefp.h>
33 #endif
34 
35 #include "fpmath.h"
36 #include "math.h"
37 #include "math_private.h"
38 
39 long double
40 roundl(long double x)
41 {
42 	long double t;
43 	uint16_t hx;
44 
45 	GET_LDBL_EXPSIGN(hx, x);
46 	if ((hx & 0x7fff) == 0x7fff)
47 		return (x + x);
48 
49 	ENTERI();
50 
51 	if (!(hx & 0x8000)) {
52 		t = floorl(x);
53 		if (t - x <= -0.5L)
54 			t += 1;
55 		RETURNI(t);
56 	} else {
57 		t = floorl(-x);
58 		if (t + x <= -0.5L)
59 			t += 1;
60 		RETURNI(-t);
61 	}
62 }
63