1 /* $NetBSD: flt_rounds.c,v 1.12 2015/03/19 21:22:59 joerg Exp $ */
2
3 /*
4 * Copyright (c) 1996 Mark Brinicombe
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by Mark Brinicombe
18 * for the NetBSD Project.
19 * 4. The name of the author may not be used to endorse or promote products
20 * derived from this software without specific prior written permission
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34 #include <sys/cdefs.h>
35 #if defined(LIBC_SCCS) && !defined(lint)
36 __RCSID("$NetBSD: flt_rounds.c,v 1.12 2015/03/19 21:22:59 joerg Exp $");
37 #endif /* LIBC_SCCS and not lint */
38
39 #include "namespace.h"
40 #include <ieeefp.h>
41 #include <float.h>
42 #include <stdint.h>
43 #include <powerpc/fpu.h>
44
45 static const int map[] = {
46 1, /* round to nearest */
47 0, /* round to zero */
48 2, /* round to positive infinity */
49 3 /* round to negative infinity */
50 };
51
52 int
__flt_rounds(void)53 __flt_rounds(void)
54 {
55 #ifdef _SOFT_FLOAT
56 return map[fpgetround()];
57 #else
58 union {
59 double u_d;
60 uint64_t u_fpscr;
61 } ud;
62
63 __asm volatile("mffs %0" : "=f"(ud.u_d));
64 return map[((uint32_t)ud.u_fpscr & FPSCR_RN)];
65 #endif
66 }
67