{File name:  BootKernel.mc

 Last Edited: Jozef Furst, January 7, 1982  11:13 AM: loading KCtl with F000
 Last Edited: Jim Frandeen, August 21, 1981  10:19 AM: changes for new assembler
 Last Edited: Jarvis, March 23, 1981  9:32 AM
 Description: Production Kernel,
 Author: Jarvis,
 Created: November 7, 1980  11:22 AM,
 Dennis Grundler:  2-Sep-84 15:42:50, add copyright notice.
}

{ 	Copyright (C) 1980, 1981, 1982 by Xerox Corporation.  All rights reserved.}

SetTask[7]; StartAddress[KGo];

Set[IOPInMode, 1];	{IOP port input mode}
Set[IOPAWMode, 3];	{IOP port alwaysWU mode}

{the code at KGo runs only once can be overlaid, and therefore goes outside the kernel area}
KGo:	ClrIntErr, CANCELBR[$, 0F], RCnt ¬ 0F,	c*, at[0FDE]; {reset the world}
	MCtl¬ 0,	c*, at[0FDF];
	KCtl¬ RCnt LRot12,	c*, at[0FDD];
	DCtl¬ 3, {this saves a couple of instructions in Phase0}	c*, at[0FDC]; {display black, enable task}
	PCtl¬ 0,	c*, at[0FDB];
	EICtl¬ 0,	c*, at[0FDA];
	EOCtl¬ 0,	c*, at[0FD9];
	passTraps¬ 0,	c*, at[0FD8];

Reserve[0, 0FD7];
	{
	Phase0Protected (Protected.mc, IOPBoot.mc) resides in 0 - 00FF
	Phase0 (Phase0.mc, DiskBootDLion.mc, EtherBoot.mc) resides in 0100 - 0FDF
	The BootKernel resides in 0FE0 - 0FFF
	Part of the BootKernel that can be overlaid resides in 0FD8 - 0FDF
	}

KEntry:	uKSaveR¬ rK,	c*;
	rK¬ RShift1 ~IOPStatus,	c*;
	uIOPCtlSave¬ rK,	c*;
	IOPCtl¬ IOPInMode,	c*; {Enable IOP port}

KRefresh:	Refresh,	c*;
	Refresh,	c*;
	Refresh,	c*;

KLoop:	Xbus¬ IOPStatus, XLDisp,	c*; {IOPReq?, x.8 guaranteed 0}
	rK¬ rK+1, NibCarryBr, BRANCH[$, KCommand],	c*;
	BRANCH[KLoop, KRefresh],	c*;

{here for kernel command from IOP}
KCommand:	Xbus¬ 0, XC2npcDisp, CANCELBR[$, 1],	c*;
KCommand1:	BRANCH[$, KDisp, 1],	c*;
	Xbus¬ 0, XC2npcDisp, GOTO[KCommand1],	c*;

KDisp:	Noop,	c1;
	Xbus¬ IOPIData, XDisp,	c2;
	DISP2[KTable],	c3;

KTable:	ExitKernel,	c1, at[0C, 10, KTable];
	rK¬ uKSaveR,	c2;
	IOPCtl¬ uIOPCtlSave, GOTO[KEntry],	c3;

KRefCmd:	Refresh, GOTO[KRefresh], {sneak in an extra refresh}	c1, at[0D, 10, KTable];
KCmd2:	GOTO[KCmd2],	c*, at[0E, 10, KTable];
KCmd3:	GOTO[KCmd3],	c*, at[0F, 10, KTable];