1/*	$NetBSD: fpsetround.c,v 1.5 2009/01/25 16:44:41 skrll Exp $	*/
2
3/*	$OpenBSD: fpsetround.c,v 1.3 2002/10/21 18:41:05 mickey Exp $	*/
4
5/*
6 * Written by Miodrag Vallat.  Public domain
7 */
8
9#include <sys/cdefs.h>
10#if defined(LIBC_SCCS) && !defined(lint)
11__RCSID("$NetBSD: fpsetround.c,v 1.5 2009/01/25 16:44:41 skrll Exp $");
12#endif /* LIBC_SCCS and not lint */
13
14#include <sys/types.h>
15#include <ieeefp.h>
16
17fp_rnd
18fpsetround(fp_rnd rnd_dir)
19{
20	uint64_t fpsr;
21	fp_rnd old;
22
23	__asm volatile("fstd %%fr0,0(%1)" : "=m" (fpsr) : "r" (&fpsr) : "memory");
24	old = (fp_rnd)(fpsr >> 41) & 0x03;
25	fpsr = (fpsr & 0xfffff9ff00000000LL) |
26	    ((uint64_t)(rnd_dir & 0x03) << 41);
27	__asm volatile("fldd 0(%0),%%fr0" : : "r" (&fpsr) : "memory");
28	return (old);
29}
30