1*2fa7e141Sandvar /* $NetBSD: flt_rounds.c,v 1.2 2022/04/08 10:17:52 andvar Exp $ */
2beb9c6d1Smatt
3beb9c6d1Smatt /*-
4beb9c6d1Smatt * Copyright (c) 2014 The NetBSD Foundation, Inc.
5beb9c6d1Smatt * All rights reserved.
6beb9c6d1Smatt *
7beb9c6d1Smatt * This code is derived from software contributed to The NetBSD Foundation
8beb9c6d1Smatt * by Matt Thomas of 3am Software Foundry.
9beb9c6d1Smatt *
10beb9c6d1Smatt * Redistribution and use in source and binary forms, with or without
11beb9c6d1Smatt * modification, are permitted provided that the following conditions
12beb9c6d1Smatt * are met:
13beb9c6d1Smatt * 1. Redistributions of source code must retain the above copyright
14beb9c6d1Smatt * notice, this list of conditions and the following disclaimer.
15beb9c6d1Smatt * 2. Redistributions in binary form must reproduce the above copyright
16beb9c6d1Smatt * notice, this list of conditions and the following disclaimer in the
17beb9c6d1Smatt * documentation and/or other materials provided with the distribution.
18beb9c6d1Smatt *
19beb9c6d1Smatt * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20beb9c6d1Smatt * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21beb9c6d1Smatt * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22beb9c6d1Smatt * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23beb9c6d1Smatt * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24beb9c6d1Smatt * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25beb9c6d1Smatt * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26beb9c6d1Smatt * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27beb9c6d1Smatt * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28beb9c6d1Smatt * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29beb9c6d1Smatt * POSSIBILITY OF SUCH DAMAGE.
30beb9c6d1Smatt */
31beb9c6d1Smatt
32beb9c6d1Smatt #include <sys/cdefs.h>
33beb9c6d1Smatt #if defined(LIBC_SCCS) && !defined(lint)
34*2fa7e141Sandvar __RCSID("$NetBSD: flt_rounds.c,v 1.2 2022/04/08 10:17:52 andvar Exp $");
35beb9c6d1Smatt #endif /* LIBC_SCCS and not lint */
36beb9c6d1Smatt
37beb9c6d1Smatt #include <sys/param.h>
38beb9c6d1Smatt #include <sys/types.h>
39beb9c6d1Smatt #include <ieeefp.h>
40beb9c6d1Smatt
41beb9c6d1Smatt #include <aarch64/armreg.h>
42beb9c6d1Smatt
43beb9c6d1Smatt
44beb9c6d1Smatt /*
45beb9c6d1Smatt * Return the current FP rounding mode
46beb9c6d1Smatt *
47beb9c6d1Smatt * Returns:
48beb9c6d1Smatt * 0 - round to zero
49beb9c6d1Smatt * 1 - round to nearest
50*2fa7e141Sandvar * 2 - round to positive infinity
51beb9c6d1Smatt * 3 - round to negative infinity
52beb9c6d1Smatt *
53beb9c6d1Smatt * However, the rounding modes stored in the FPCR are:
54beb9c6d1Smatt * 0 - round to nearest
55*2fa7e141Sandvar * 1 - round to positive infinity
56beb9c6d1Smatt * 2 - round to negative infinity
57beb9c6d1Smatt * 3 - round to zero
58beb9c6d1Smatt *
59beb9c6d1Smatt * To convert, just add 1 and then mask with 3.
60beb9c6d1Smatt */
61beb9c6d1Smatt
62beb9c6d1Smatt int __flt_rounds(void);
63beb9c6d1Smatt
64beb9c6d1Smatt int
__flt_rounds(void)65beb9c6d1Smatt __flt_rounds(void)
66beb9c6d1Smatt {
67beb9c6d1Smatt return (__SHIFTOUT(reg_fpcr_read(), FPCR_RMODE) + 1) & 3;
68beb9c6d1Smatt }
69