1 /* $OpenBSD: fpsetround.c,v 1.2 2021/04/30 16:13:00 drahn Exp $ */
2 /*
3 * Copyright (c) 2021 Mark Kettenis <kettenis@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 #include <sys/types.h>
19 #include <ieeefp.h>
20
21 fp_rnd
fpsetround(fp_rnd rnd_dir)22 fpsetround(fp_rnd rnd_dir)
23 {
24 uint32_t frm;
25
26 __asm volatile ("fsrm %0, %1" : "=r"(frm) : "r"(rnd_dir));
27
28 /* Truncating to 2 bits means both RNE and RMM become FP_RN. */
29 return frm & 0x3;
30 }
31