:TITLE[Fetch.0mc...January 12, 1983  10:50 AM, van Melle];

Set[FetchDebug, 0];
Set[NoInterrupts, 0];

*	GOTO[REFILLY],LOADPAGE[0],at[0001];

*	only required on pages that contain NextInst/NextData's
REFILLY:
*	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[0377] ;*page  0 alto
*	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[0777] ;*page  1 alto
*	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[1377] ;*page  2 alto
*	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[1777] ;*page  3 alto

	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[2377] ;*page  4
lspNextInstP4:	lu _ NextInst[IBuf];
lnixP4:		NIRET;

	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[2777] ;*page  5
lspNextInstP5:	lu _ NextInst[IBuf];
lnixP5:		NIRET;

	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[3377] ;*page  6
lspNextInstP6:	lu _ NextInst[IBuf];
lnixP6:		NIRET;

	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[3777] ;*page  7
lspNextInstP7:	lu _ NextInst[IBuf], at[P7TailLoc];	* placed for overlays
lnixP7:		NIRET;

*	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[4377] ;*page 10

*	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[4777] ;*page 11

	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[5377] ;*page 12
lspNextInstP12:	lu _ NextInst[IBuf];
lnixP12: 	NIRET;

*	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[5777] ;*page 13 alto
*	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[6377] ;*page 14 alto

	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[6777] ;*page 15
lspNextInstP15:	lu _ NextInst[IBuf];
lnixP15: 	NIRET;

	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[7377] ;*page 16
lspNextInstP16:	lu _ NextInst[IBuf];
lnixP16: 	NIRET;

*	PFetch4[PCB, IBuf, 4], gotop[RefillIBuf], at[7777] ;*page 17 - can't
	onpage[17];
lspNextInstP17:	loadpage[7];
		gotop[lspNextInstP7];


	OnPage[0];

RefillIBuf:
	PCB _ (PCB) + (4c), at[340];
	PCF _ Rzero, at[341];
	nop, at[342];
	return, at[343];		* Wait for page fault

onpage[pgJump];

* If the PFETCH4 faults, the fault handler will set IBUF to -1s and
* continue as if nothing happened.  The fault happens after the 3rd
* instruction past the pfetch is executed.  The fault handler destroys
* the return link.  The micro instruction being executed must be on
* pgJump for this special action to occur.

ReturnOp:
	return, opcode[374];	* Used by Fault for first mi NextData case

PFop:
	PFETCH4[PCB, IBUF, 0], opcode[377];	* This will page fault
	IBUF _ IBUF, goto[nxiLBL];


* Come here when IntPending instead of to next opcode

	onpage[opPage0];

TakeInterrupt:
	T _ (SStkP&NStkP) xor (377c), skip;	* maybe these can be the same
NwwOp:	T _ (SStkP&NStkP) xor (377c), opcode[000];
	lspL1 _ IP[RSImage]c;			* RS232 Image Register
	Stkp _ lspL1, lspL1 _ T, NoRegILockOK;
	T _ Stack _ (Stack) and not (IntPendingBit);
	Stkp _ lspL1, RS232 _ T;

:IF[WindFlg];
	lu _ (NWW) and not (BothKeyMasks), goto[NoInterrupt, R<0];
				* test for interrupts other than lisp/bcpl key
	NWW _ (NWW) and not (BcplKeyMask), goto[NWWPunt, alu#0];
				* yes, do them by punting to bcpl
	AC2 _ KbdFXP, skip[alu#0];	* Skip if no interrupts: shouldn't happen?
	  goto[NoInterrupt];			* spurious
	NWW _ 100000c;			* turn off interrupts before switching
	loadpage[pgLisp0];
	AC3 _ 177400c, gotop[CheckForBackup];	* AC3<0 signals contextswitch

NoInterrupt:
	T _ (PCXReg) - 1;	* need to back up the PC before resuming
	lspL1 _ T;
	PCF _ lspL1;			* wait for PCF to get written
	goto[nxiLBL];

:ELSE;				* pre-Wind, always do Nww
	LoadPage[pgLisp0];
	gotop[lspNWWInt];
:ENDIF;

%
:IF[NoInterrupts];
	T _ (PCXReg);
	lspL1 _ T;
	lspL1 _ (lspL1) - (1c);
	nop;
	PCF _ (lspL1);
	nop;
	lu _ NextInst[IBuf];
	NIRET;
:ELSE;
	LoadPage[pgLisp0];
	gotop[lspNWWInt];
:ENDIF;
%


	onpage[4];
lspRetP4: return;

	onpage[5];
lspRetP5: return;

	onpage[6];
lspRetP6: return;

	onpage[10];
lspRetP10: return;

	onpage[11];
lspRetP11: return;

	onpage[15];
lspRetP15: return;

	onpage[16];
lspRetP16: return;

	onpage[17];
lspRetP17: return;



	onpage[5];
lspUfnxP5:
	loadpage[pgUfnx];
	gotop[lspUfnxP4];

	onpage[6];
lspUfnxP6:
	loadpage[pgUfnx];
	gotop[lspUfnxP4];

	onpage[7];
lspUfnxP7:
	loadpage[pgUfnx];
	gotop[lspUfnxP4];

	onpage[10];
lspUfnxP10:
	loadpage[pgUfnx];
	gotop[lspUfnxP4];

	onpage[11];
lspUfnxP11:
	loadpage[pgUfnx];
	gotop[lspUfnxP4];

	onpage[12];
lspUfnxP12:
	loadpage[pgUfnx];
	gotop[lspUfnxP4];

	onpage[15];
lspUfnxP15:
	loadpage[pgUfnx];
	gotop[lspUfnxP4];

	onpage[16];
lspUfnxP16:
	loadpage[pgUfnx];
	gotop[lspUfnxP4];

	onpage[17];
lspUfnxP17:
	loadpage[pgUfnx];
	gotop[lspUfnxP4];


	:END[Fetch];