1 /* $NetBSD: flt_rounds.c,v 1.2 2022/04/08 10:17:52 andvar Exp $ */
2
3 /*-
4 * Copyright (c) 2014 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Matt Thomas of 3am Software Foundry.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 __RCSID("$NetBSD: flt_rounds.c,v 1.2 2022/04/08 10:17:52 andvar Exp $");
35 #endif /* LIBC_SCCS and not lint */
36
37 #include <sys/param.h>
38 #include <sys/types.h>
39 #include <ieeefp.h>
40
41 #include <aarch64/armreg.h>
42
43
44 /*
45 * Return the current FP rounding mode
46 *
47 * Returns:
48 * 0 - round to zero
49 * 1 - round to nearest
50 * 2 - round to positive infinity
51 * 3 - round to negative infinity
52 *
53 * However, the rounding modes stored in the FPCR are:
54 * 0 - round to nearest
55 * 1 - round to positive infinity
56 * 2 - round to negative infinity
57 * 3 - round to zero
58 *
59 * To convert, just add 1 and then mask with 3.
60 */
61
62 int __flt_rounds(void);
63
64 int
__flt_rounds(void)65 __flt_rounds(void)
66 {
67 return (__SHIFTOUT(reg_fpcr_read(), FPCR_RMODE) + 1) & 3;
68 }
69