flt_rounds.c revision 1.4 
1/*	$NetBSD: flt_rounds.c,v 1.4 2005/12/24 21:42:32 perry Exp $	*/
2
3/*	$OpenBSD: flt_rounds.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: flt_rounds.c,v 1.4 2005/12/24 21:42:32 perry Exp $");
12#endif /* LIBC_SCCS and not lint */
13
14#include <sys/types.h>
15#include <machine/float.h>
16
17static const int map[] = {
18	1,	/* round to nearest */
19	0,	/* round to zero */
20	2,	/* round to positive infinity */
21	3	/* round to negative infinity */
22};
23
24int
25__flt_rounds(void)
26{
27	uint64_t fpsr;
28
29	__asm volatile("fstd %%fr0,0(%1)" : "=m" (fpsr) : "r" (&fpsr));
30	return map[(fpsr >> 41) & 0x03];
31}
32