xref: /relibc/openlibm/src/s_lround.c (revision b0b27a0ff417e8deadca7e0d71a7365eef14a6ad)
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 <sys/cdefs.h>
28 #include <sys/limits.h>
29 #include <fenv.h>
30 #include <openlibm.h>
31 
32 #ifndef type
33 //__FBSDID("$FreeBSD: src/lib/msun/src/s_lround.c,v 1.2 2005/04/08 00:52:16 das Exp $");
34 #define type		double
35 #define	roundit		round
36 #define dtype		long
37 #define	DTYPE_MIN	LONG_MIN
38 #define	DTYPE_MAX	LONG_MAX
39 #define	fn		lround
40 #endif
41 
42 /*
43  * If type has more precision than dtype, the endpoints dtype_(min|max) are
44  * of the form xxx.5; they are "out of range" because lround() rounds away
45  * from 0.  On the other hand, if type has less precision than dtype, then
46  * all values that are out of range are integral, so we might as well assume
47  * that everything is in range.  At compile time, INRANGE(x) should reduce to
48  * two floating-point comparisons in the former case, or TRUE otherwise.
49  */
50 static const type dtype_min = DTYPE_MIN - 0.5;
51 static const type dtype_max = DTYPE_MAX + 0.5;
52 #define	INRANGE(x)	(dtype_max - DTYPE_MAX != 0.5 || \
53 			 ((x) > dtype_min && (x) < dtype_max))
54 
55 dtype
56 fn(type x)
57 {
58 
59 	if (INRANGE(x)) {
60 		x = roundit(x);
61 		return ((dtype)x);
62 	} else {
63 		feraiseexcept(FE_INVALID);
64 		return (DTYPE_MAX);
65 	}
66 }
67