xref: /netbsd-src/lib/libm/src/s_lrint.c (revision 464b32545a12041970bd21a7f657b5bce306b323)
1 /*-
2  * Copyright (c) 2005 David Schultz <das@FreeBSD.ORG>
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, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include "namespace.h"
28 
29 #include <sys/cdefs.h>
30 #include <fenv.h>
31 #include <math.h>
32 
33 #ifndef stype
34 #ifdef __FreeBSD__
35 __FBSDID("$FreeBSD: head/lib/msun/src/s_lrint.c 140088 2005-01-11 23:12:55Z das $");
36 #else
37 __RCSID("$NetBSD: s_lrint.c,v 1.1 2017/05/06 18:03:24 christos Exp $");
38 #endif
39 #define stype		double
40 #define	roundit		rint
41 #define dtype		long
42 #define	fn		lrint
43 #endif
44 
45 /*
46  * C99 says we should not raise a spurious inexact exception when an
47  * invalid exception is raised.  Unfortunately, the set of inputs
48  * that overflows depends on the rounding mode when 'dtype' has more
49  * significant bits than 'stype'.  Hence, we bend over backwards for the
50  * sake of correctness; an MD implementation could be more efficient.
51  */
52 dtype
fn(stype x)53 fn(stype x)
54 {
55 	fenv_t env;
56 	dtype d;
57 
58 	feholdexcept(&env);
59 	d = (dtype)roundit(x);
60 	if (fetestexcept(FE_INVALID))
61 		feclearexcept(FE_INEXACT);
62 	feupdateenv(&env);
63 	return (d);
64 }
65