static void timer_thread_func(struct AmiThread *aAmiThread)
{
	usecs_t Interval;
	ULONG Signal, ThreadSignal, TimerSignal;
	struct timeval OldTime, NewTime;
 
	/* Determine the time at which the first timer request was made so we can determine the */
	/* real interval of the timer when it is called back, thus avoiding drift */
 
	gettimeofday(&OldTime, NULL);
 
	/* And request a timer callback after 1 MS, just to kickstart the timer processing.  Allegro's */
	/* tick counter will handle calculating how often to call the callback in the future */
 
	amithread_request_timeout(aAmiThread, 1000);
 
	ThreadSignal = (1 << aAmiThread->at_ThreadSignalBit);
	TimerSignal = (1 << aAmiThread->at_TimerMsgPort->mp_SigBit);
 
	for ( ; ; )
	{
		Signal = IExec->Wait(ThreadSignal | TimerSignal);
 
		if (Signal & ThreadSignal)
		{
			break;
		}
 
		if (Signal & TimerSignal)
		{
			/* Calculate actual time elapsed */
 
			gettimeofday(&NewTime, NULL);
			Interval = ((NewTime.tv_sec - OldTime.tv_sec) * 1000000 + (NewTime.tv_usec - OldTime.tv_usec));
			OldTime = NewTime;
 
			/* Handle a tick */
 
			Interval = timer_thread_handle_tick(Interval);
			amithread_request_timeout(aAmiThread, Interval);
		}
	}
 
	amithread_remove_sender(&gGraphicsThread);
}