1/*	$OpenBSD: flt_rounds.c,v 1.6 2022/12/27 17:10:05 jmc Exp $	*/
2/*	$NetBSD: flt_rounds.c,v 1.1 2000/12/29 20:13:48 bjh21 Exp $	*/
3
4/*
5 * Copyright (c) 1996 Mark Brinicombe
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following 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 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *      This product includes software developed by Mark Brinicombe
19 *	for the NetBSD Project.
20 * 4. The name of the author may not be used to endorse or promote products
21 *    derived from this software without specific prior written permission
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 */
34
35#include <sys/types.h>
36#include <ieeefp.h>
37#include <float.h>
38
39static const int map[] = {
40	1,	/* round to nearest */
41	2,	/* round to positive infinity */
42	3,	/* round to negative infinity */
43	0	/* round to zero */
44};
45
46/*
47 * Return the current FP rounding mode
48 *
49 * Returns:
50 *	0 - round to zero
51 *	1 - round to nearest
52 *	2 - round to positive infinity
53 *	3 - round to negative infinity
54 *
55 * ok all we need to do is get the current FP rounding mode
56 * index our map table and return the appropriate value.
57 *
58 * HOWEVER:
59 * The ARM FPA codes the rounding mode into the actual FP instructions
60 * so there is no such thing as a global rounding mode.
61 * The default is round to nearest if rounding is not explicitly specified.
62 * FP instructions generated by GCC will not explicitly specify a rounding
63 * mode.
64 *
65 * So the best we can do it to return the rounding mode FP instructions
66 * use if rounding is not specified which is round to nearest.
67 *
68 * This could change in the future with new floating point emulators or
69 * soft float FP libraries.
70 */
71
72int
73__flt_rounds()
74{
75	return(map[fpgetround()]);
76}
77DEF_STRONG(__flt_rounds);
78