xinu-avr/include/timer.h

/*General purpose timer */

extern	unsigned long	clktime;   /* current time in secs since boot	*/
extern  unsigned long  count1000;  /* ms since last clock tick          */

extern	qid16	sleepq;		/* queue for sleeping processes		*/
extern	int32	slnonempty;	/* nonzero if sleepq is nonempty	*/
extern	int32	*sltop;		/* ptr to key in first item on sleepq	*/
extern	uint32	preempt;	/* preemption counter 			*/