xref: /openbsd/lib/libm/src/s_lrintl.c (revision 8932bfb7)
1 /*	$OpenBSD: s_lrintl.c,v 1.1 2011/07/06 00:02:42 martynas Exp $	*/
2 
3 /*-
4  * Copyright (c) 2005 David Schultz <das@FreeBSD.ORG>
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, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 #include <fenv.h>
31 #include <math.h>
32 
33 #ifndef type
34 #if 0
35 __FBSDID("$FreeBSD: src/lib/msun/src/s_lrint.c,v 1.1 2005/01/11 23:12:55 das Exp $");
36 #endif
37 #define type		long double
38 #define	roundit		rintl
39 #define dtype		long
40 #define	fn		lrintl
41 #endif
42 
43 /*
44  * C99 says we should not raise a spurious inexact exception when an
45  * invalid exception is raised.  Unfortunately, the set of inputs
46  * that overflows depends on the rounding mode when 'dtype' has more
47  * significant bits than 'type'.  Hence, we bend over backwards for the
48  * sake of correctness; an MD implementation could be more efficient.
49  */
50 dtype
51 fn(type x)
52 {
53 	fenv_t env;
54 	dtype d;
55 
56 	feholdexcept(&env);
57 	d = (dtype)roundit(x);
58 	if (fetestexcept(FE_INVALID))
59 		feclearexcept(FE_INEXACT);
60 	feupdateenv(&env);
61 	return (d);
62 }
63