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$L1CM
DEBUGGING PROGRAM
$B2
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OBJECT: DBUG
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$P2
@THIS PROGRAM IS USED AS AN AID TO DEBUGGING PROGRAMS,
IT MAY BE USED TO:-
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$B0 1) .SET AND .CLEAR BREAKPOINTS
$B0 2) @DUMP OUT THE .PSECT, .REGISTERS AND/OR THE .IMP .STACK.
$B0 3) .EXAMINE AND .CHANGE LOCATIONS IN CORE.
$B0 4) .DUMP GENERAL AREAS OF CORE.
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$P2
.DEBUG INDICATES ITS READINESS TO ACCEPT COMMANDS
BY TYPING .'DEBUG:'. @THE FOLLOWING COMMANDS MAY BE USED.
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$B1
$I-1 .T - $T+1 @SET @TASK NUMBER OF PROGRAM TO BE DEBUGGED.
$I-1 .B - $T+1 @SET BREAKPOINT.
$I-1 .C - $T+1 @CLEAR BREAKPOINT.
$I-1 .N - $T+1 @SET A NEW PROGRAM CODE BASE.
$I-1 .R - $T+1 @DUMP THE .REGISTERS, LINE NUMBER ETC.
$I-1 .P - $T+1 @DUMP THE .PSECT.
$I-1 .E - $T+1 @LIST THE LOADED .EXTERNALS.
$I-1 .I - $T+1 @DUMP THE .IMP STACK.
$I-1 .A - $T+1 @DO .'P', .'R', .'E',  AND .'I'.
$I-1 .D - $T+1 @DUMP AN AREA OF CORE.
$I-1 .O - $T+1 @CHANGE THE OUTPUT DEVICE.
$I-1 .W - $T+1 .WAIT .DEBUG.
$I-1 .S - $T+1 @STOP .DEBUG.
$I-1 .? - $T+1 @PRINT OPTIONS.
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$P1
@IN ADDITION TO THESE COMMANDS, THERE IS AN IMPLIED COMMAND,
ACTIVATED BY TYPING AN OCTAL DIGIT, THAT ENTERS
THE LOCATION EXAMINATION/CHANGE PART OF .DEBUG.
$P2
@A DETAILED DESCRIPTION OF EACH COMMAND FOLLOWS.
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T - SET TASK NUMBER
$P1 @THE PROMPT .'TASK .NUMBER .(OCTAL):' IS OUTPUT AND THE
(OCTAL) .ID OF THE PROGRAM TO BE DEBUGGED SHOULD BE ENTERED.
@IT SHOULD BE NOTED THAT COMMANDS .'R', .'P', .'I', AND .'A'
WILL ONLY EXECUTE IF A TASK NUMBER IS SET.  .'B'
WILL USE A BASE OF .ZERO FOR BREAKPOINTS.
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B - SET BREAKPOINT
$P1
@THE PROMPT .'ADDR:' IS OUTPUT, THE REPLY IS THE .RELATIVE ADDRESS
(WRT THE START OF THE PROGRAM) OF THE DESIRED BREAKPOINT.  @DEBUG
WILL REMEMBER THE CONTENTS AND PLACE A .'BR $.' IN THE
LOCATION. @THIS WILL CAUSE THE PROGRAM TO SIT IN A LOOP IF
IT EXECUTES THAT INSTRUCTION.
$P1
@DEBUG REPLIES:
$B0 .BP: N .ADDR: N2 .CONT= N3 -  WHERE 'N' IS THE
BREAKPOINT NUMBER (BETWEEN 0 AND 20), 'N2' IS THE PHYSICAL
ADDRESS, AND 'N3' THE ORIGINAL CONTENTS.
$P1 @THE MESSAGE .'BP .TABLE .FULL' IS OUTPUT IF MORE
THAN 21 BREAKPOINTS ARE USED.
@SEE THE COMMAND .'N' FOR SETTING BREAKPOINTS IN EXTERNAL
ROUTINES.
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C - CLEAR BREAKPOINTS
$P1 @PROMPTS .'NO?'. @THE 
BREAKPOINT NUMBER SHOULD BE TYPED. .'A' OR '-1' IS TYPED
IF .ALL THE BREAKPOINTS ARE TO BE CLEARED. @IF THE
SPECIFIC BREAKPOINT HAS NOT BEEN SET, THE MESSAGE '?' IS
OUTPUT. @THE ORIGINAL CONTENTS ARE REPLACED.
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N - SET A NEW PROGRAM CODE BASE
$P1 @PROMPTS .'NEW .PROGRAM .CODE:'. @REPLY GIVING THE NEW
ADDRESS. @THIS COMMAND IS USEFUL FOR PROGRAMS USING EXTERNAL
ROUTINES.  @TO SET A BREAKPOINT IN AN EXTERNAL ROUTINE
, THE CODE BASE IS SET TO THAT OF THE EXTERNAL 
ROUTINE AND THE RELATIVE ADDRESS SPECIFIED. @THIS DOES NOT
EFFECT ANY PREVIOUSLY SET BREAKPOINTS.
$P1 @A SECOND USE IS TO PUT A BREAKPOINT INTO A PROGRAM
BEFORE IT STARTS EXECUTING.
 IE THE CODE IS .LOADED FROM DISC, THE BASE SET BY .'N',
BREAKPOINTS SET WITH RELATIVE ADDRESSES AND FINALLY THE PROGRAM
IS .STARTED USING .'OIT'.  @THIS ALLOWS DEBUGGING OF A PROGRAM
THAT CRASHES IMMEDIATELY AFTER STARTUP.
$B3 $L1C
R - PRINT REGISTERS AND OTHER PROGRAM INFORMATION.
$P1 @THIS COMMAND PRINTS THE REGISTERS OF THE NOMINATED TASK.
@IN ADDITION, IF THE TASK HAS HAD AN ADDRESS ERROR OR
SIMILAR FAULT, THE REGISTERS AT THE TIME OF THE CRASK ARE ALSO
PRINTED (ALTHOUGH .R3 IS DESTROYED BY THE SYSTEM).
$P1 @THE .LINE .NUMBER OF THE PROGRAM, ITS .CODE .ADDRESS, 
THE .IMP .DISPLAY ADDRESS AND THE .MINIMUN .STACK ARE
ALSO PRINTED.
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P - PRINT THE PSECT
$P1 @THE .PSECT (OWN SYSTEM VARIABLES) OF THE NOMINATED TASK
IS PRINTED.
$V6
$V10
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E - LIST THE EXTERNALS USED BY THE PROGRAM
$P2 @THIS COMMAND WILL LIST THE EXTERNAL ROUTINES
WHICH HAVE BEEN LOADED BY THE PROGRAM, GIVING THE
NAME FOLLOWED BY THE ADDRESS IT WAS LOADED AT.
$V10
$B3 $L1C
I - PRINT THE IMP STACK
$P1 @THE ENTIRE .IMP .STACK IS PRINTED ON THE OUTPUT DEVICE.
$B0 .NOTE: @THE BASE OF THE .DISPLAY (IE THE START OF THE VARIABLES)
IS NOT THE SAME AS THE START OF THE STACK.
 @THERE ARE .PERM VARIABLES ON THE TOP OF THE STACK. .'R' GIVES THE
START OF THE .DISPLAY.
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A - PRINT ALL
$P1 @THE COMMAND EXECUTES A PRINT PSECT .(P), PRINT REGISTERS .(R) ,
 LIST OF EXTERNALS .(E)
AND THE .IMP STACK .(I). @THIS COMMAND IS USEFUL FOR DUMPING ALL
THE RELEVANT INFORMATION ABOUT A PROGRAM ONTO THE LINE PRINTER
(SEE COMMAND .'O').
$B3
$L1C
D - DUMP AN AREA OF CORE
$P1 @PROMPTS .'FROM:' AND .'LENGTH:'. @BOTH NUMBERS
SHOULD BE TYPED IN OCTAL AND THE AREA OF CORE FROM .'FROM'
TO .'FROM+LENGTH' IS OUTPUT.
$B1 .NOTE: 1) @ON ALL THE DUMPS .'ZEROES' IS OUPUT IF ONE
OR MORE ENTIRE LINE CONTAINS ZERO.
$B0 2) @AN .ISO EQUIVALENT IS PRINTED ON THE .RHS OF THE DUMP.
$B3 $L1C
O - CHANGE THE OUTPUT DEVICE
$P1 @PROMPTS .'STREAM:'. @THE REPLY IS THE STREAM NUMBER FOR
THE OUTPUT OF COMMANDS .R,P,I,A AND .D. @THE LINE PRINTER
IS '2' AND THE TELETYPE '0'.
$P1 @THIS COMMAND WILL CHANGE TO SPECIFY A DEVICE OR FILE
BY NAME IN THE NEAR FUTURE.
$B3
$L1C
W - WAIT DEBUG
$P1 @THIS COMMAND IS USED TO SUSPEND .DEBUG IF IT IS NECESSARY
TO INPUT TO A PROGRAM ON THE SAME TELETYPE. @IT IS RESTARTED
BY $B0  .'OIT:CO .DBUG'.
$B3 $L1C
S - STOP DEBUG
$P1 @DEBUG HALTS.
$B0 @NOTE: AT PRESENT BREAKPOINTS ARE NOT CLEARED.
$V10
$B3
$L1C
IMPLIED COMMAND TO EXAMINE/CHANGE CORE ADDRESSES
$P1 @THIS COMMAND ACCEPTS THE FOLLOWING INSTRUCTIONS:-
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@PLEASE NOTE THAT ALL NUMBERS ARE TYPED IN OCTAL.
$B0 .N $T4 : PRINTS CONTENTS OF .N.
$B0 .N+C $T4 : PRINTS CONTENTS OF .(N+ PROGRAM BASE).
$B0 .N+I $T4 : PRINTS CONTENTS OF .(N+ .IMP .STK BASE).
$B0 .N+RM $T4 : PRINTS CONTENTS OF .(N+REGISTER .M)
$B1 .N(+ OPTIONS)=M $T4 : PUTS .M INTO .N
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$B2
EG: .DEBUG:100 (CR) - WILL PRINT CONTENTS OF LOCN 100.
$B0 $C+4 .DEBUG:100+R5 (CR) - WILL PRINT CONTENTS OF 100
ON FROM REG. 5.
$B0 $C+4 .DEBUG:100+R5=200 (CR) - DIITO, EXCEPT PLANTS 200.
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