1 /*
2 * (C)2012 Michael Duane Rice All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met:
7 *
8 * Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer. Redistributions in binary
10 * form must reproduce the above copyright notice, this list of conditions
11 * and the following disclaimer in the documentation and/or other materials
12 * provided with the distribution. Neither the name of the copyright holders
13 * nor the names of contributors may be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 /* $Id: set_system_time.c 2356 2013-04-21 16:20:01Z swfltek $ */
30
31 /*
32 * Set the system time. The values passed are assumed to represent local
33 * standard time, such as would be obtained from the typical Real Time Clock
34 * integrated circuit. It is necessary for this to be atomic, as the value may be
35 * incremented at interrupt time.
36 */
37
38 #include <time.h>
39 extern volatile time_t __system_time;
40
41 void
set_system_time(time_t timestamp)42 set_system_time(time_t timestamp)
43 {
44
45 asm volatile(
46 "in __tmp_reg__, __SREG__" "\n\t"
47 "cli" "\n\t"
48 ::
49 );
50 __system_time = timestamp;
51 asm volatile(
52 "out __SREG__, __tmp_reg__" "\n\t"
53 ::
54 );
55 }
56