+/*
+256boss - bootable launcher for 256byte intros
+Copyright (C) 2018-2019 John Tsiombikas <nuclear@member.fsf.org>
+
+This program 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.
+
+This program 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.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <https://www.gnu.org/licenses/>.
+*/
#ifndef _TIMER_H_
#define _TIMER_H_
-unsigned long nticks;
+#include "config.h"
+
+#define MSEC_TO_TICKS(ms) ((ms) * TICK_FREQ_HZ / 1000)
+#define TICKS_TO_MSEC(tk) ((tk) * 1000 / TICK_FREQ_HZ)
+
+volatile unsigned long nticks;
void init_timer(void);
+/*
int sys_sleep(int sec);
void sleep(unsigned long msec);
+*/
+
+/* schedule a function to be called 'msec' milliseconds into the future
+ * warning: this function will be called directly from the timer interrupt, and
+ * must be extremely quick.
+ */
+void set_alarm(unsigned long msec, void (*func)(void));
+void cancel_alarm(void (*func)(void));
#endif /* _TIMER_H_ */