{Page Numbers: Yes X: 500 Y: -.5" First Page: 1
Heading:

}{Protected.mcPage}

{File name: Protected.mc
Description: Protected microcode for Initial,
Author: Jarvis,
Created: December 5, 1980,
Last Edited: Jarvis, March 23, 1981 9:52 AM}

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

Reserve[OverlayStart, 0FFF];

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];

Refresh:Refresh, CANCELBR[$, 0F],c1;
Noop,c2;
Noop,c3;
Refresh,c1;
Noop,c2;
ClrDPRq, GOTO[Refresh],c3;