1 /* Enable floating-point exceptions.
2 Copyright (C) 2004 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Aldy Hernandez <aldyh@redhat.com>, 2004.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
19
20 #include "fenv_libc.h"
21 #include <syscall.h>
22 #include <sys/prctl.h>
23
24 int
feenableexcept(int excepts)25 feenableexcept (int excepts)
26 {
27 unsigned int result = 0, pflags, r;
28 INTERNAL_SYSCALL_DECL (err);
29
30 INTERNAL_SYSCALL (prctl, err, 2, PR_GET_FPEXC, &pflags);
31
32 /* Save old enable bits. */
33 if (pflags & PR_FP_EXC_OVF)
34 result |= FE_OVERFLOW;
35 if (pflags & PR_FP_EXC_UND)
36 result |= FE_UNDERFLOW;
37 if (pflags & PR_FP_EXC_INV)
38 result |= FE_INVALID;
39 if (pflags & PR_FP_EXC_DIV)
40 result |= FE_DIVBYZERO;
41 if (pflags & PR_FP_EXC_RES)
42 result |= FE_INEXACT;
43
44 if (excepts & FE_INEXACT)
45 pflags |= PR_FP_EXC_RES;
46 if (excepts & FE_DIVBYZERO)
47 pflags |= PR_FP_EXC_DIV;
48 if (excepts & FE_UNDERFLOW)
49 pflags |= PR_FP_EXC_UND;
50 if (excepts & FE_OVERFLOW)
51 pflags |= PR_FP_EXC_OVF;
52 if (excepts & FE_INVALID)
53 pflags |= PR_FP_EXC_INV;
54 r = INTERNAL_SYSCALL (prctl, err, 2, PR_SET_FPEXC, pflags);
55 if (INTERNAL_SYSCALL_ERROR_P (r, err))
56 return -1;
57
58 return result;
59 }
60