1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
|
/* $OpenBSD: except.c,v 1.12 2010/05/08 19:16:33 naddy Exp $ */
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <assert.h>
#include <ieeefp.h>
#include <float.h>
#include <err.h>
volatile sig_atomic_t signal_status;
volatile const double one = 1.0;
volatile const double zero = 0.0;
volatile const double huge = DBL_MAX;
volatile const double tiny = DBL_MIN;
void
sigfpe(int sig, siginfo_t *si, void *v)
{
char buf[132];
if (si) {
snprintf(buf, sizeof(buf), "sigfpe: addr=%p, code=%d\n",
si->si_addr, si->si_code);
write(1, buf, strlen(buf));
}
_exit(signal_status);
}
int
main(int argc, char *argv[])
{
struct sigaction sa;
volatile double x;
if (argc != 2) {
fprintf(stderr, "usage: %s condition\n", argv[0]);
exit(1);
}
/*
* check to make sure that all exceptions are masked and
* that the accumulated exception status is clear.
*/
assert(fpgetmask() == 0);
assert(fpgetsticky() == 0);
memset(&sa, 0, sizeof(sa));
sa.sa_sigaction = sigfpe;
sa.sa_flags = SA_SIGINFO;
sigaction(SIGFPE, &sa, NULL);
signal_status = 1;
if (strcmp(argv[1], "fltdiv") == 0) {
/* trip divide by zero */
x = one / zero;
assert(fpgetsticky() & FP_X_DZ);
fpsetsticky(0);
/* and now unmask to get a signal */
signal_status = 0;
fpsetmask(FP_X_DZ);
x = one / zero;
} else if (strcmp(argv[1], "fltinv") == 0) {
/* trip invalid operation */
x = zero / zero;
assert(fpgetsticky() & FP_X_INV);
fpsetsticky(0);
/* and now unmask to get a signal */
signal_status = 0;
fpsetmask(FP_X_INV);
x = zero / zero;
} else if (strcmp(argv[1], "fltovf") == 0) {
/* trip overflow */
x = huge * huge;
assert(fpgetsticky() & FP_X_OFL);
fpsetsticky(0);
/* and now unmask to get a signal */
signal_status = 0;
fpsetmask(FP_X_OFL);
x = huge * huge;
} else if (strcmp(argv[1], "fltund") == 0) {
/* trip underflow */
x = tiny * tiny;
assert(fpgetsticky() & FP_X_UFL);
fpsetsticky(0);
/* and now unmask to get a signal */
signal_status = 0;
fpsetmask(FP_X_UFL);
x = tiny * tiny;
} else {
errx(1, "unrecognized condition %s", argv[1]);
}
/*
* attempt to trigger the exception on machines where
* floating-point exceptions are deferred.
*/
x = one * one;
errx(1, "signal wasn't caught");
}
|
