:TITLE[Timer];

	SetTask[TTask];
	OnPage[TimerInitPage];
*Initialize Notifies here to set up timers (this is throwaway code)
InitTimers:
	TimerTemp _ (100000C), at[TimerInitLoc];
ClrTimers:	LoadTimer[TimerTemp]; *Clear out all Timers
	RSImage _ T _ 0C;
	RS232 _ T; *Zap RS232
	RTimer _ (50000C);	*Set up the Refresh time
	RTimer _ (RTimer) OR (257C);	*simple timer,value 10d,slot 17b
	TimerTemp _ (TimerTemp) + 1, ResetMemErrs; *Clear any pending memory errors
	LU _ (TimerTemp) AND (17C);		*there are 16d timers
	REFR _ T _  (0C), dblgoto[InitDone, ClrTimers, ALU=0];
InitDone:
	LU _ Timer; *read to clear pending wakeups
	LOADTIMER[RTimer]; *load refresh timer
	TimerBasehi _ T, loadpage[TimerPage]; *initialize high base register
	RTCLOW _ 1c, gotop[TimerSetTPC]; *RTCLOW is made odd so that timer updating won't start
*until the memory has been initialized.

	Onpage[TimerPage];
TimerSetTPC: call[TimerRet];
*Timer wakeups come here
TimerWakeup:		*Timer wakeups come here
	Dispatch[Timer,14,4];
	TimerBase _ 400c, DISP[Timers]; *initialize low base register

*Timer dispatch table for task 16 (all entries are not used)
Timers:
	Refresh[REFR], goto[RefreshNext], AT[TimerTable,00] ;*slot 17
	goto[BadTimerWake], T _ 16c, AT[TimerTable,01]; *slot 16
	goto[BadTimerWake], T _ 15c, AT[TimerTable,02]; *slot 15
	goto[BadTimerWake], T _ 14c, AT[TimerTable,03]; *slot 14
	goto[BadTimerWake], T _ 13c, AT[TimerTable,04]; *slot 13
	goto[BadTimerWake], T _ 12c, AT[TimerTable,05]; *slot 12
	goto[BadTimerWake], T _ 11c, AT[TimerTable,06]; *slot 11
	goto[BadTimerWake], T _ 10c, AT[TimerTable,07]; *slot 10
	goto[BadTimerWake], T _ 7c, AT[TimerTable,10]; *slot 7
*Ethernet Output Notify slot (Add copies with EOTask1, EOTask2 ... if multiple controllers).
	TimerTemp _ OR[lshift[EOTask,14],AND[7400,EOTimerDoneLoc]]C, GOTO[TEONotify], AT[TimerTable,11]; 
	goto[BadTimerWake], T _ 5c, AT[TimerTable,12]; *slot 5
	goto[BadTimerWake], T _ 4c, AT[TimerTable,13]; *slot 4
	goto[BadTimerWake], T _ 3c, AT[TimerTable,14]; *slot 3
	goto[BadTimerWake], T _ 2c, AT[TimerTable,15]; *slot 2
	goto[BadTimerWake], T _ 1c, AT[TimerTable,16]; *slot 1
	goto[BadTimerWake], T _ 0c, AT[TimerTable,17]; *slot 0

*Wrong value in timer dispatch comes here with channel number in T:
BadTimerWake:  Breakpoint, return;

*Notify for Ethernet output (Only one copy required)
TEONotify:
	TimerTemp _ (TimerTemp) or (AND[0377, EOTimerDoneLoc]C); * Low 8 bits of APC
	APC&APCTask _ TimerTemp; *Notify Ethernet output task, don't restart timer
TimerRet:	return, AT[TimerTable,24]; *Must be MouseHalt+1 for proper restarting.

*Refresh has been started.
RefreshNext:
	AddToTimer[RTIMER]; *load the refresh timer

* check for Midas halt
CheckMidas:
	T _ (FFAULT) and (10000c);	* check for Midas present and mouse halt
	lu _ (PRINTER) and (T);
	dblgoto[MouseHalt,CheckRTC,ALU#0];


MouseHalt:	goto[.], SETFAULT, AT[TimerTable,23]; *Midas mouse halt is a task 16 breakpoint that was
*not set by the user.  Midas continues by going to location 7004 (which contains a return).

CheckRTC:	RTCLOW _ (RTCLOW) + (154c), dblgoto[RTCOff,UpdateRTC, ROdd];


RTCOff:	RTCLOW _ 1c, goto[RTCRet]; *RTC has not been started yet.

*Check for RTC update required.
*The real time clock is set up for 100nsec main clock rate, i.e. 64us/timer round.
*Each tick, we add 108d (154b) to RTCLOW, which will cause it to carry every
*65536/108 = 606.8 times the code is run.  606.8 * 64 = 38836us.  The equivalent
*Alto number is 39009.5us, so the clock will run slightly fast.

UpdateRTC:	
	T _ 30c, skip[carry]; *RTCLOW overflowed.  Increment VM 430
RTCRet:	REFR _ (REFR) + (20C), return; *increment the refresh address
	PFetch1[TimerBase,TimerTemp]; *Increment VM 430
	TimerTemp _ (TimerTemp)+1;
	PStore1[TimerBase,TimerTemp], goto[RTCRet];

:END[Timer];(1795)\1763f1 47f0 544f1 154f0 167f8 24f0 476f8 33f0