summaryrefslogtreecommitdiff
path: root/libgfortran/intrinsics/system_clock.c
blob: 6385c4f0c95dc01117e08e4fa23f82174a39f7d8 (plain)
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
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
/* Implementation of the SYSTEM_CLOCK intrinsic.
   Copyright (C) 2004, 2005, 2007, 2009, 2010, 2011 Free Software
   Foundation, Inc.

This file is part of the GNU Fortran runtime library (libgfortran).

Libgfortran is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public
License as published by the Free Software Foundation; either
version 3 of the License, or (at your option) any later version.

Libgfortran is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

#include "libgfortran.h"

#include <limits.h>

#include "time_1.h"


/* POSIX states that CLOCK_REALTIME must be present if clock_gettime
   is available, others are optional.  */
#if defined(HAVE_CLOCK_GETTIME) || defined(HAVE_CLOCK_GETTIME_LIBRT)
#ifdef CLOCK_MONOTONIC
#define GF_CLOCK_MONOTONIC CLOCK_MONOTONIC
#else
#define GF_CLOCK_MONOTONIC CLOCK_REALTIME
#endif
#endif

/* Weakref trickery for clock_gettime().  On Glibc, clock_gettime()
   requires us to link in librt, which also pulls in libpthread.  In
   order to avoid this by default, only call clock_gettime() through a
   weak reference. 

   Some targets don't support weak undefined references; on these
   GTHREAD_USE_WEAK is 0. So we need to define it to 1 on other
   targets.  */
#ifndef GTHREAD_USE_WEAK
#define GTHREAD_USE_WEAK 1
#endif

#if SUPPORTS_WEAK && GTHREAD_USE_WEAK && defined(HAVE_CLOCK_GETTIME_LIBRT)
static int weak_gettime (clockid_t, struct timespec *) 
  __attribute__((__weakref__("clock_gettime")));
#endif


/* High resolution monotonic clock, falling back to the realtime clock
   if the target does not support such a clock.

   Arguments:
   secs     - OUTPUT, seconds
   nanosecs - OUTPUT, nanoseconds

   If the target supports a monotonic clock, the OUTPUT arguments
   represent a monotonically incrementing clock starting from some
   unspecified time in the past.

   If a monotonic clock is not available, falls back to the realtime
   clock which is not monotonic.

   Return value: 0 for success, -1 for error. In case of error, errno
   is set.
*/
static int
gf_gettime_mono (time_t * secs, long * nanosecs)
{
  int err;
#ifdef HAVE_CLOCK_GETTIME
  struct timespec ts;
  err = clock_gettime (GF_CLOCK_MONOTONIC, &ts);
  *secs = ts.tv_sec;
  *nanosecs = ts.tv_nsec;
  return err;
#else
#if defined(HAVE_CLOCK_GETTIME_LIBRT) && SUPPORTS_WEAK && GTHREAD_USE_WEAK
  if (weak_gettime)
    {
      struct timespec ts;
      err = weak_gettime (GF_CLOCK_MONOTONIC, &ts);
      *secs = ts.tv_sec;
      *nanosecs = ts.tv_nsec;
      return err;
    }
#endif
  err = gf_gettime (secs, nanosecs);
  *nanosecs *= 1000;
  return err;
#endif
}

extern void system_clock_4 (GFC_INTEGER_4 *, GFC_INTEGER_4 *, GFC_INTEGER_4 *);
export_proto(system_clock_4);

extern void system_clock_8 (GFC_INTEGER_8 *, GFC_INTEGER_8 *, GFC_INTEGER_8 *);
export_proto(system_clock_8);


/* prefix(system_clock_4) is the INTEGER(4) version of the SYSTEM_CLOCK
   intrinsic subroutine.  It returns the number of clock ticks for the current
   system time, the number of ticks per second, and the maximum possible value
   for COUNT.  On the first call to SYSTEM_CLOCK, COUNT is set to zero. */

void
system_clock_4(GFC_INTEGER_4 *count, GFC_INTEGER_4 *count_rate,
	       GFC_INTEGER_4 *count_max)
{
#undef TCK
#define TCK 1000
  GFC_INTEGER_4 cnt;
  GFC_INTEGER_4 mx;

  time_t secs;
  long nanosecs;

  if (sizeof (secs) < sizeof (GFC_INTEGER_4))
    internal_error (NULL, "secs too small");

  if (gf_gettime_mono (&secs, &nanosecs) == 0)
    {
      GFC_UINTEGER_4 ucnt = (GFC_UINTEGER_4) secs * TCK;
      ucnt += (nanosecs + 500000000 / TCK) / (1000000000 / TCK);
      if (ucnt > GFC_INTEGER_4_HUGE)
	cnt = ucnt - GFC_INTEGER_4_HUGE - 1;
      else
	cnt = ucnt;
      mx = GFC_INTEGER_4_HUGE;
    }
  else
    {
      if (count != NULL)
	*count = - GFC_INTEGER_4_HUGE;
      if (count_rate != NULL)
	*count_rate = 0;
      if (count_max != NULL)
	*count_max = 0;
      return;
    }

  if (count != NULL)
    *count = cnt;
  if (count_rate != NULL)
    *count_rate = TCK;
  if (count_max != NULL)
    *count_max = mx;
}


/* INTEGER(8) version of the above routine.  */

void
system_clock_8 (GFC_INTEGER_8 *count, GFC_INTEGER_8 *count_rate,
		GFC_INTEGER_8 *count_max)
{
#undef TCK
#define TCK 1000000000
  GFC_INTEGER_8 cnt;
  GFC_INTEGER_8 mx;

  time_t secs;
  long nanosecs;

  if (sizeof (secs) < sizeof (GFC_INTEGER_4))
    internal_error (NULL, "secs too small");

  if (gf_gettime_mono (&secs, &nanosecs) == 0)
    {
      GFC_UINTEGER_8 ucnt = (GFC_UINTEGER_8) secs * TCK;
      ucnt += (nanosecs + 500000000 / TCK) / (1000000000 / TCK);
      if (ucnt > GFC_INTEGER_8_HUGE)
	cnt = ucnt - GFC_INTEGER_8_HUGE - 1;
      else
	cnt = ucnt;
      mx = GFC_INTEGER_8_HUGE;
    }
  else
    {
      if (count != NULL)
	*count = - GFC_INTEGER_8_HUGE;
      if (count_rate != NULL)
	*count_rate = 0;
      if (count_max != NULL)
	*count_max = 0;

      return;
    }

  if (count != NULL)
    *count = cnt;
  if (count_rate != NULL)
    *count_rate = TCK;
  if (count_max != NULL)
    *count_max = mx;
}