'The following is an FSMC code fragment.  You must complete the specification.

'CLK       /MARCAR   F2        GOSYNC    F1        F0        FLAG
'RAMLREG   NC        NC        NC        GND       NC        NC        
'Q0        Q1        Q2        /MARLOAD  /MARCNT   /DOWNCNT  /REGLOAD  
'/WE       NC        VCC       

'/MARCAR   F2        GOSYNC    F1        F0        FLAG      RAMLREG
'/MARCNT   Q0        Q1        Q2        GND       NC        NC        
'NC        /MARCNT3  /MARCNT2  /REGTORAM /SWTTORAM CLRFLAG   SETFLAG   
'NC        NC        VCC       
begin_p
negative MARLOAD@18, MARCNT@19, DOWNCNT@20, MARCAR@2, REGLOAD@21, WE@22, 
negative REGTORAM@118, SWTTORAM@119, MARCNT2@117, MARCNT3@116, REGLOAD2@115;
positive CLRFLAG@120, SETFLAG@121;
device 20v8;
MARCNT3 = MARCNT + MARCNT2;
end_p
'This is the Idle state, where the machine sits when it isn't doing anything.
'Note that if FLAG is set and the switches indicate that we have just done
'a FindMax, we write the swap register to RAM and back to the compare 
'register.  Then, we clear the flag.

Idle:	if (/F2 * F1 * F0) {		'Findmax routine selected
		if (GOSYNC) then
			goto ClearMar;	'Clear MAR and start FindMax.
		else if (FLAG) {	'Max in swap reg
			REGTORAM, WE;	'Send to ram
			REGLOAD;	'Write back to compare register
			CLRFLAG;	'Clear flag
		} else
			stay;
	} else	if (GOSYNC * /F2 * /F1 * /F0) {	'Load Address selected.
		MARLOAD;		'Load MAR
		stay;

	} else	if (GOSYNC * /F2 * /F1 * F0) {	'Examine Memory selected.
		REGLOAD;		'Load Register
		MARCNT;			'Increase MAR
		stay;

	} else	if (GOSYNC * /F2 * F1 * /F0) {	'Store Selected.
		SWTTORAM;		'Drive Switches
		WE;			'Enable Writes
		MARCNT;			'Increase MAR
		stay;

	} else	if (GOSYNC * F2) {	'No-Op Selected.
		goto ClearMar;	'Go To the Bubble Sort routine
	} else
		stay;

'This state is used to clear the MAR to zero before starting the FindMax
'routine.  We have to do this, since the 'LS169 doesn't have a clear input.
'Note that, when we count down, MARCAR is true when MAR=0.

ClearMar:DOWNCNT;		'We want the counter to count down
	 if (/MARCAR) {		'Not at zero,
		MARCNT;		'  so count down.
		stay;
	 } else {
	 	CLRFLAG;
                REGLOAD;
		if (F2)
			goto StartSort;
		else
			goto FindMax;
	 }

'Following is the FindMax routine.  Note that the flag is used to maintain
'the end-of-ram condition.  It is set when the mar=15.  Then, the mar is
'allowed to wrap around to zero.  When the flag is set, the maximum value
'will be in the compare register.  Thus, we assert 'REGLOAD' to place this
'value in the swap register, then return to the idle state with the 
'flag still set.  The idle state will complete the process by writing
'this value back to RAM location zero and clearing the flag.

'Use of the flag is not necessary (why??).  However, we are attempting
'to test all of our hardware.

FindMax:if (/FLAG) {
		if (/RAMLREG) then
			REGLOAD;	'load new register value
		if (MARCAR) then
			SETFLAG;	'All done
		MARCNT;			'Next location
		stay;
	} else {
		REGLOAD;		'Send max value to swap register
		goto Idle;		'Will finish in idle state.
	}


StartSort:if (RAMLREG) {		'(i+1) < (i) ?
		REGLOAD2;		'Get (i) ready and load (i+1)
		goto Swap;

	} else if (MARCAR) {
		if (FLAG) {		'We Swapped something
			goto ClearMar;
		} else {
			goto Idle;
		}

	} else {
		REGLOAD2;		'Load (i+1) into Register
		MARCNT2;
		stay;
	}


Swap:	WE;				'Enable Writes
	REGTORAM;			'Drive Register (i) into i+1
	REGLOAD2;			'Load Register with (i)
	DOWNCNT;			'Count Down on MAR;
	MARCNT2;
	goto Swap2;

Swap2:	WE;				'Enable Writes
	REGTORAM;			'Drive Register (i+1) into i
	MARCNT2;			'Count Up on MAR
	SETFLAG;
	goto StartSort;