xref: /openbsd/lib/libc/arch/sh/gen/fpsetround.c (revision 5af055cd)
1 /*	$OpenBSD: fpsetround.c,v 1.3 2014/04/18 15:09:52 guenther Exp $	*/
2 /*
3  * Copyright (c) 2006 Miodrag Vallat.
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, this permission notice, and the disclaimer below
8  * appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include <sys/types.h>
20 #include <ieeefp.h>
21 
22 fp_rnd
23 fpsetround(fp_rnd rnd_dir)
24 {
25 	register_t fpscr, nfpscr;
26 #if defined(__SH4__) && !defined(__SH4_NOFPU__)
27 	extern register_t __fpscr_values[2];
28 #endif
29 
30 	__asm__ volatile ("sts fpscr, %0" : "=r" (fpscr));
31 	if (rnd_dir == FP_RN || rnd_dir == FP_RZ) {
32 		nfpscr = (fpscr & ~0x03) | rnd_dir;
33 #if defined(__SH4__) && !defined(__SH4_NOFPU__)
34 		__fpscr_values[0] = (__fpscr_values[0] & ~0x03) | rnd_dir;
35 		__fpscr_values[1] = (__fpscr_values[1] & ~0x03) | rnd_dir;
36 #endif
37 		__asm__ volatile ("lds %0, fpscr" : : "r" (nfpscr));
38 	}
39 	/* else how report an error? */
40 
41 	return (fpscr & 0x03);
42 }
43