%
% 20-INTERRUPT.RED -- Crude Interrupt Handler for DEC-20
% Author: M. L. Griss and D. Morrison
% Utah Symbolic Computation Group
% Computer Science Dept.
% University of Utah
% Date: 20 May 1981
% Copyright (c) University of Utah
% It is assumed that the system dependent portion of an implementation will
%supply the following 3 functions:
%
% InitializeInterrupts
% EnableInterrupts
% DisableInterrupts
% DismissInterrupt
%
% While these are machine dependent, the interrupt handlers themselves are
% are expected to generally be machine independent, simply calling
% DismissInterrupt when done. The assignment of terminal-initiated interrupts
% to keys is machine dependent.
imports '(Addr2ID); % for code-address-to-symbol
on Syslisp;
%internal WARRAY InterruptLevelTable[2],
% InterruptPCStorage[2],
% InterruptChannelTable[35];
FLUID '(InterruptLevelTable
LoadAverageStore
InterruptPCStorage
InterruptChannelTable
);
compiletime << WCONST !.FHSLF=8#400000;>>;
if FUnBoundP 'XJsysError then <<
syslsp procedure XJsysError(); % autoloading stub
<< Load JSYS;
Apply(function XJsysError, '()) >>;
>>;
syslsp procedure InitializeInterrupts();
% Initializes interrupt handlers for both machine- and terminal-initiated
% interrupts. Most cases should dispatch to machine-independent handlers.
% Leaves the interrupt system enabled.
% In this Tops-20 (machine-code) version we currently handle:
% just playing, for now
begin
(LispVar InterruptLevelTable):=GtWarray 3;
(LispVar InterruptPCStorage):=GtWarray 3;
(LispVar InterruptChannelTable):=GtWarray 36;
(LispVar LoadAverageStore) := MkString(4, char BLANK);
ClearInterrupts();
% set up interrupt tables -- see Monitor Calls Manual for details
For i := 0:35 do %/ Some bug, wiped out next one when after
(LispVar InterruptChannelTable)[i]:=0;
for i := 0:2 do
(LispVar InterruptLevelTable)[i]:=(LispVar InterruptPCStorage) + i;
% Terminal Interupts (Procedure on channel/level)
% Note LEVEL is 1,2,3
PutInterrupt(0,1,'DoControlG);
PutInterrupt(1,1,'SaveAndCallControlT); % control T not working yet
PutInterrupt(2,1,'SaveAndBreak);
% special channels
PutInterrupt(6,1,'ArithOverflow);
PutInterrupt(7,1,'FloatArithOverflow);
PutInterrupt(9,1,'PushDownOverflow);
% Now Install tables
Xjsys0(!.FHSLF,
XWD((LispVar InterruptLevelTable),
(LispVar InterruptChannelTable)),0,0,const jsSIR);
EnableInterrupts();
ActivateChannel(0);
ActivateChannel(1);
ActivateChannel(2);
ActivateChannel(6);
ActivateChannel(7);
ActivateChannel(9);
PutTerminalInterrupt(7,0); % Char CNTRL-G on 0
PutTerminalInterrupt(4,0); % Char CNTRL-D on 2
PutTerminalInterrupt(20,1); % Char cntrl-t on 1, not working yet
PutTerminalInterrupt(0,2); % Char BREAK on 2
PutTerminalInterrupt(2,2); % Char cntrl-B on 2
ClearInterrupts();
end;
syslsp procedure SetContinueAddress(Level,Address);
begin scalar x;
x:=(LispVar InterruptLevelTable)[Level-1];
x[0]:=address;
end;
% FunctionCellLocation is used by LAP
off Syslisp;
fluid '(!*WritingFaslFile);
lisp procedure SetContinueFunction(Level,FunctionName);
begin scalar !*WritingFaslFile;
SetContinueAddress(Level, FunctionCellLocation FunctionName);
end;
lisp procedure PutInterrupt(Channel,Level,ActionId);
begin scalar !*WritingFaslFile;
WPutV(InterruptChannelTable,
Channel,
XWD(Level, FunctionCellLocation ActionId));
end;
on Syslisp;
syslsp procedure XWD(a,b);
Lor(Lsh(a,18),b);
syslsp procedure PutTerminalInterrupt(CntrlChar,Channel);
Xjsys0(XWD(CntrlChar,Channel),0,0,0,const jsATI);
syslsp procedure RemoveTerminalInterrupt(CntrlChar,Channel);
Xjsys0(XWD(CntrlChar,Channel),0,0,0,const jsDTI);
syslsp procedure ReadTerminalWord;
Xjsys1(0,0,0,0,Const jsRTIW);
syslsp procedure SetTerminalWordBit(n);
<<XJsys0(Lor(ReadTerminalLWord(),Dec20Bit n),0,0,const jsSTIW);
ReadTerminalWord()>>;
syslsp procedure SetTerminalWord(MSK);
<<Xjsys0(Lor(ReadTerminalWord(),MSK),0,0,0,const jsSTIW);
ReadTerminalWord()>>;
syslsp procedure ClearInterrupts;
Xjsys0(0,0,0,0,const jsCIS); % clear any pending interrupts
syslsp procedure SignalChannel n; %. Test on channel n
Xjsys0(!.FHSLF,Dec20Bit n,0,0,const jsIIC);
syslsp procedure EnableInterrupts;
Xjsys0(!.FHSLF,0,0,0,const jsEIR);
syslsp procedure DisableInterrupts;
Xjsys0(!.FHSLF,0,0,0,const jsDIR);
syslsp procedure ActivateChannel(n); %. Inform OS of channel
Xjsys0(!.FHSLF,Dec20Bit n,0,0,const jsAIC);
syslsp procedure DeActivateChannel(n); %. Inform OS of channel
Xjsys0(!.FHSLF,Dec20Bit n,0,0,const jsDIC);
syslsp procedure Dec20Bit n; %. Bits [0 to 35]
Dec20Fld(1,35-n);
syslsp procedure Dec20Fld(x,y);
LSH(x,y);
syslsp procedure DismissInterrupt;
% Warning: an interrupt handler should not attempt to resume if may have
% caused a garbage collection.
Xjsys0(0,0,0,0,const jsDEBRK);
% ----- Some default handlers ----------
syslsp procedure DoControlG;
<< ClearTerminalInputBuffer(); % CFIBF
ChannelWriteChar(LispVAR StdOUT!*, Char BELL);
ErrorPrintF "*** Restarting";
SetContinueFunction(1,'Reset);
DismissInterrupt()>>;
syslsp procedure ClearTerminalInputBuffer();
Xjsys0(8#100,0,0,0,const jsCFIBF);
syslsp procedure ArithOverflow;
<<SetContinueFunction(1,'ArithOverFlowError);
DismissInterrupt()>>;
syslsp procedure ArithOverFlowError;
StdError('"Integer overflow");
syslsp procedure FloatArithOverflow;
<<SetContinueFunction(1,'FloatArithOverFlowError);
DismissInterrupt()>>;
syslsp procedure FloatArithOverFlowError;
StdError('"Floating point overflow");
lap '((!*entry PushDownOverflow expr 0)
(sub (reg st) (lit (halfword 1000 1000))) % move the stack back
(!*MOVE (WConst 1) (REG 1))
(movei 2 ErrorAddress)
(!*CALL SetContinueAddress)
(!*JCALL DismissInterrupt)
ErrorAddress
(!*MOVE '"Stack overflow" (reg 1))
(!*JCALL StdError) % normal error
);
lap '((!*entry FindLoadAverage expr 0)
(move 1 (lit (fullword 8#000014000014))) % 1 min avg, .systa
(getab)
(!*EXIT 0)
(hrrz 2 (fluid LoadAverageStore))
(hrli 2 8#10700) % make a byte pointer
(exch 1 2)
(move 3 (lit (fullword 8#024037020200)))
(flout)
(!*EXIT 0)
(!*EXIT 0)
);
syslsp procedure DoControlT();
begin scalar RunningFunctionID, CameFrom;
% ClearTerminalInputBuffer();
FindLoadAverage();
CameFrom := INF ((LispVar InterruptPCStorage)[0]);
RunningFunctionID := code!-address!-to!-symbol CameFrom or 'UNKNOWN;
ErrorPrintF("^T: in %p at %o, load %w",
RunningFunctionID, CameFrom, LispVar LoadAverageStore);
end;
>>;
syslsp procedure DoBreak();
begin scalar RunningFunctionID, CameFrom, CurrentChannel;
ClearTerminalInputBuffer();
CameFrom := INF( (LispVar InterruptPCStorage)[0]);
RunningFunctionID := code!-address!-to!-symbol CameFrom or 'UNKNOWN;
CurrentChannel := WRS NIL;
ErrorPrintF("*** Break in %p at %o", RunningFunctionID, CameFrom);
ErrorSet(quote Break(), NIL, NIL);
WRS CurrentChannel;
end;
lap '((!*Entry SaveAndCallControlT expr 0)
%
% Save all regs, call DoControlT and dismiss
%
(adjsp (reg st) 14) % allocate 14 slots on the stack
(hrri (reg nil) (indexed (reg st) -13)) % set up BLT pointer
(hrli (reg nil) 1) % move regs 1..14 onto the stack
(blt (reg nil) (indexed (reg st) 0))
(move (reg nil) (fluid nil)) % fix reg nil
(!*CALL DoControlT) % call the function
(hrli (reg nil) (indexed (reg st) -13))
(hrri (reg nil) 1)
(blt (reg nil) 14) % move the registers back off the stack
(move (reg nil) (fluid nil)) % restore reg nil again
(adjsp (reg st) -14)
(debrk)
);
>>;
lap '((!*Entry SaveAndBreak expr 0)
%
% Save all regs, call DoBreak and dismiss
%
(adjsp (reg st) 14) % allocate 14 slots on the stack
(hrri (reg nil) (indexed (reg st) -13)) % set up BLT pointer
(hrli (reg nil) 1) % move regs 1..14 onto the stack
(blt (reg nil) (indexed (reg st) 0))
(move (reg nil) (fluid nil)) % fix reg nil
(!*CALL DoBreak) % call the function
(hrli (reg nil) (indexed (reg st) -13))
(hrri (reg nil) 1)
(blt (reg nil) 14) % move the registers back off the stack
(move (reg nil) (fluid nil)) % restore reg nil again
(adjsp (reg st) -14)
(debrk)
);
InitializeInterrupts();
off syslisp;
END;