xref: /openbsd-src/lib/libc/arch/arm/gen/fpsetround.c (revision b02ee2d0b169340f8c05ac869f38b89250c96865)
1*b02ee2d0Skettenis /*	$OpenBSD: fpsetround.c,v 1.1 2018/02/28 11:16:54 kettenis Exp $	*/
2*b02ee2d0Skettenis /*
3*b02ee2d0Skettenis  * Copyright (c) 2018 Mark Kettenis <kettenis@openbsd.org>
4*b02ee2d0Skettenis  *
5*b02ee2d0Skettenis  * Permission to use, copy, modify, and distribute this software for any
6*b02ee2d0Skettenis  * purpose with or without fee is hereby granted, provided that the above
7*b02ee2d0Skettenis  * copyright notice and this permission notice appear in all copies.
8*b02ee2d0Skettenis  *
9*b02ee2d0Skettenis  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10*b02ee2d0Skettenis  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11*b02ee2d0Skettenis  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12*b02ee2d0Skettenis  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13*b02ee2d0Skettenis  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14*b02ee2d0Skettenis  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15*b02ee2d0Skettenis  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16*b02ee2d0Skettenis  */
17*b02ee2d0Skettenis 
18*b02ee2d0Skettenis #include <ieeefp.h>
19*b02ee2d0Skettenis #ifdef SOFTFLOAT_FOR_GCC
20*b02ee2d0Skettenis #include "softfloat-for-gcc.h"
21*b02ee2d0Skettenis #endif
22*b02ee2d0Skettenis #include "milieu.h"
23*b02ee2d0Skettenis #include <softfloat.h>
24*b02ee2d0Skettenis #include <stdint.h>
25*b02ee2d0Skettenis 
26*b02ee2d0Skettenis __weak_alias(_fpsetround,fpsetround);
27*b02ee2d0Skettenis 
28*b02ee2d0Skettenis fp_rnd
fpsetround(fp_rnd rnd_dir)29*b02ee2d0Skettenis fpsetround(fp_rnd rnd_dir)
30*b02ee2d0Skettenis {
31*b02ee2d0Skettenis 	uint32_t old, new;
32*b02ee2d0Skettenis 
33*b02ee2d0Skettenis 	__asm volatile("vmrs %0, fpscr" : "=r" (old));
34*b02ee2d0Skettenis 	new = old & ~(3 << 22);
35*b02ee2d0Skettenis 	new |= (rnd_dir & 3) << 22;
36*b02ee2d0Skettenis 	__asm volatile("vmsr fpscr, %0" :: "r" (new));
37*b02ee2d0Skettenis 
38*b02ee2d0Skettenis 	float_rounding_mode = rnd_dir;
39*b02ee2d0Skettenis 
40*b02ee2d0Skettenis 	return ((old >> 22) & 3);
41*b02ee2d0Skettenis }
42