timer-unix-c.h

00001 /* Opus Una - A Small Cooperative Multitasking Kernel in C
00002  *
00003  * Copyright (C) 2011 by Ivo van Poorten <ivop@euronet.nl>
00004  * This file is licensed under the terms of the GNU Lesser
00005  * General Public License, version 3.
00006  */
00007 
00008 /* Run the kernel as a process on Unix */
00009 
00010 #include "timer.h"
00011 #include "kernel.h"
00012 
00013 #include <sys/time.h>
00014 #include <signal.h>
00015 #include <string.h>
00016 #include <unistd.h>
00017 
00018 static void timer_sr(int x) {
00019     ou_ticks++;
00020     ou_update_tasks();
00021 }
00022 
00023 void ou_start_timer(void) {
00024     struct itimerval val;
00025     struct sigaction act;
00026 
00027     memset(&act, 0, sizeof(act));
00028 
00029     act.sa_handler = timer_sr;
00030     sigaction(SIGALRM, &act, NULL);     // signal() is not portable
00031 
00032     val.it_interval.tv_usec = 10000;    // 10ms
00033     val.it_interval.tv_sec = 0;
00034     val.it_value.tv_usec = 10000;       // 10ms
00035     val.it_value.tv_sec = 0; 
00036     setitimer(ITIMER_REAL, &val, NULL);
00037 }
00038 
00039 void ou_idle(void) {
00040     usleep(5);                  // save power/cpu time/et cetera...
00041 }