head     1.1;
branch   1.1.1;
access   ;
symbols  start:1.1.1.1 Xerox:1.1.1;
locks    ; strict;
comment  @# @;


1.1
date     2001.08.12.22.22.26;  author freier;  state Exp;
branches 1.1.1.1;
next     ;

1.1.1.1
date     2001.08.12.22.22.26;  author freier;  state Exp;
branches ;
next     ;


desc
@@



1.1
log
@Initial revision
@
text
@{File name:  Protected.mc

Last Edited: Dennis DEG       1-Sep-84 22:17:55:  Add copyright notice.
Last Edited: AeF AEF      November 16, 1981  2:22 PM: Change register names
Last Edited: Jozef JF    November 4, 1981  3:18 PM: multiple allocation corrected (Carry changed to RefCarry)
Last Edited: AeF AEF      October 23, 1981  11:40 AM: Change register names to prevent conflict with SAx00Initial.mc names
Last Edited: AeF AEF      September 11, 1981  9:52 AM: make clock update atomic
Last Edited: Jim JXF      August 19, 1981  4:30 PM: add clock update to refresh task.
Description: Protected microcode for Initial,
Author: PXJ   ,
Created: December 5, 1980,
}

{	Copyright (C) 1980, 1981 by Xerox Corporation.  All rights reserved. }

Set[OverlayStart, Add[ProtectFence, 1]];

Reserve[OverlayStart, 0FFF];
	{
	Phase0Protected (Protected.mc, IOPBoot.mc) resides in 0 - 00FF
	Phase0 (Phase0.mc, DiskBootDLion.mc, EtherBootDLion.mc) resides in 0100 - 0FDF
	The BootKernel resides in 0FE0 - 0FFF
	Part of the BootKernel that can be overlaid resides in 0FD8 - 0FDF
	}

SetTask[0];

{clobber only rC before going to external fault handler}

Trap:	rC¬ RRot1 ErrnIBnStkp, ClrIntErr, CANCELBR[$, 0F],	c1, at[0];
	[]¬ passTraps, ZeroBr,	c2;
	BRANCH[$, Trap1],	c3;
	GOTOABS[ErrorHandlerLoc],	c1; {pass the trap on}
Trap1:	acR¬ bootTrap, GOTO[catchAll2],	c1;

catchAll1:	Noop,	c1, at[Maintenance1Loc];
catchAll2:	Noop,	c2, at[Maintenance2Loc];
catchAll3:	rB¬ 0, rBrh¬ 0,	c3, at[Maintenance3Loc];
	MAR¬ [rBrh, rB+1],	c1;
	MDR¬ acR and 0FF, CANCELBR[$, 0],	c2;
	IOPCtl¬ IOPInMode,	c3; {enable IOP}
infinite:	GOTO[infinite],	c*, at[IdleLoc];

SetTask[1];  StartAddress[Refresh];

	{We come here once per line, or every 28.8 usec. 
	That means 34,722 times per second}
Refresh:	rJ ¬ rJ - 1 {Decrement clock low}, ZeroBr, Refresh, CANCELBR[$, 0F],	c1;
	BRANCH[NoCarry, RefCarry],	c2;

RefCarry:	rG ¬ rG - 1 {Decrement clock high}, GOTO[TestTimeout],	c3;
NoCarry:
	Noop,	c3;
TestTimeout:
	Ybus ¬ rJ or rG, ZeroBr, Refresh,	c1;
	rN ¬ 1, BRANCH[$, Timeout],	c2;
	ClrDPRq, GOTO[Refresh],	c3;

Timeout:	uTimeout ¬ rN, ClrDPRq, GOTO[Refresh],	c3;



@


1.1.1.1
log
@first add
@
text
@@