1*af3276d5Sguenther /* $OpenBSD: flt_rounds.c,v 1.7 2015/10/27 05:54:49 guenther Exp $ */
28d0618b8Sniklas /* $NetBSD: flt_rounds.c,v 1.1 1995/04/29 05:09:53 cgd Exp $ */
38d0618b8Sniklas
4df930be7Sderaadt /*
5df930be7Sderaadt * Copyright (c) 1995 Christopher G. Demetriou
6df930be7Sderaadt * All rights reserved.
7df930be7Sderaadt *
8df930be7Sderaadt * Redistribution and use in source and binary forms, with or without
9df930be7Sderaadt * modification, are permitted provided that the following conditions
10df930be7Sderaadt * are met:
11df930be7Sderaadt * 1. Redistributions of source code must retain the above copyright
12df930be7Sderaadt * notice, this list of conditions and the following disclaimer.
13df930be7Sderaadt * 2. Redistributions in binary form must reproduce the above copyright
14df930be7Sderaadt * notice, this list of conditions and the following disclaimer in the
15df930be7Sderaadt * documentation and/or other materials provided with the distribution.
16df930be7Sderaadt * 3. All advertising materials mentioning features or use of this software
17df930be7Sderaadt * must display the following acknowledgement:
18df930be7Sderaadt * This product includes software developed by Christopher G. Demetriou
19df930be7Sderaadt * for the NetBSD Project.
20df930be7Sderaadt * 4. The name of the author may not be used to endorse or promote products
21df930be7Sderaadt * derived from this software without specific prior written permission
22df930be7Sderaadt *
23df930be7Sderaadt * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24df930be7Sderaadt * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25df930be7Sderaadt * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26df930be7Sderaadt * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27df930be7Sderaadt * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28df930be7Sderaadt * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29df930be7Sderaadt * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30df930be7Sderaadt * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31df930be7Sderaadt * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32df930be7Sderaadt * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33df930be7Sderaadt */
34df930be7Sderaadt
35df930be7Sderaadt #include <sys/types.h>
36fba30992Sderaadt #include <float.h>
37df930be7Sderaadt
38df930be7Sderaadt static const int map[] = {
39df930be7Sderaadt 0, /* round to zero */
40df930be7Sderaadt 3, /* round to negative infinity */
41df930be7Sderaadt 1, /* round to nearest */
42df930be7Sderaadt 2 /* round to positive infinity */
43df930be7Sderaadt };
44df930be7Sderaadt
45df930be7Sderaadt int
__flt_rounds()46df930be7Sderaadt __flt_rounds()
47df930be7Sderaadt {
48df930be7Sderaadt double fpcrval;
49df930be7Sderaadt u_int64_t old;
50df930be7Sderaadt
51df930be7Sderaadt __asm__("trapb");
52df930be7Sderaadt __asm__("mf_fpcr %0" : "=f" (fpcrval));
53df930be7Sderaadt __asm__("trapb");
54df930be7Sderaadt old = *(u_int64_t *)&fpcrval;
55df930be7Sderaadt
56df930be7Sderaadt return map[(old >> 58) & 0x3];
57df930be7Sderaadt }
58*af3276d5Sguenther DEF_STRONG(__flt_rounds);
59