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01100 PPPPPPP OOOOOO OOOOOO M M AA SSSSSSS
01200 P P O O O O MM MM A A S
01300 P P O O O O M M M M A A S
01400 P P O O O O M MM M A A S
01500 PPPPPPP O O O O M M AAAAAAAA SSSSSS
01600 P O O O O M M A A S
01700 P O O O O M M A A S
01800 P O O O O M M A A S
01900 P OOOOOO OOOOOO M M A A SSSSSSS
02000
02100 P O O R M A N ' S S I M U L A
02200
02300
02400
02500
02600 A DISCRETE EVENT SIMULATION PACKAGE FOR USE WITH BLISS
02700 BASED ON SIMULA-1, SIMULA-67 AND IDEAS OF DR. W. A. WULF
02800
02900
03000
03100
03200
03300
03400
03500
03600 .
03700 POORIFIED BY AMUND LUNDE
03800
03900
04000
04100 VERSION 2
04200 CARNEGIE-MELLON UNIVERSITY, MAY 1971.
00100 I N T R O D U C T I O N
00200
00300
00400
00500 POOMAS - POOR MANS SIMULA - CONSISTS OF A SET OF BLISS ROUTINES AND
00600 MACROS WHICH FACILITATE WRITING OF DISCRETE EVENT SIMULATIONS IN
00700 BLISS. THE INFLUENCE FROM SIMULA AND SIMULA-67 ON THE DESIGN IS VERY
00800 STRONG, - TRANSLATION OF PROGRAMS FROM SIMULA INTO POOMAS/BLISS OR
00900 VICE VERSA SHOULD BE REASONABLY STRAIGHTFORWARD.
01000
01100 ONE IMPORTANT FEATURE OF SIMULA, LACKING IN POOMAS, IS THE SECURITY,
01200 IN THE SENSE THAT
01300 1) THE RESULT OF EXECUTING AN INCORRECT PROGRAM SHOULD BE PREDICT-
01400 ABLE FROM STUDYING THE PROGRAM WITHOUT RESORT TO KNOWLEDGE ABOUT THE
01500 IMPLEMENTATION, AND
01600 2) ALL DETECTABLE ERRORS SHOULD BE DETECTED.
01700 SINCE BLISS HAS NO TYPES, SECURITY CAN NOT BE IN ANY WAY COMPLETE,
01800 ALTHOUGH CONSIDERABLE CHECKING IS BUILT INTO THE POOMAS ROUTINES. THE
01900 LACK OF TYPES, IN PARTICULAR POINTERS, ALSO MAKES AUTOMATIC GARBAGE-
02000 COLLECTION IMPOSSIBLE. ALSO, SINCE THE COMPILER DOES NOT KEEP THE
02100 SYMBOL TABLE FOR 'INVISIBLE' PROCEDURE BODIES, REMOTE ACCESSING IS BY
02200 ORDINAL NO. IN THE ACTIVATION RECORD RATHER THAN BY IDENTIFIER.
02300
02400 A STUDY OF SIMULA REVEALS THREE IMPORTANT AND INDEPENDENT CONCEPTS.
02500 1) LIST PROCESSING
02600 2) COROUTINE CREATION, EXECUTION, AND ACCESS TO VARIABLES IN COROU-
02700 TINES.
02800 3) QUASI PARALLELL EXECUTION, - I.E. SEQUENCING OF PROCESSES (CO-
02900 ROUTINE INSTANCES) ACCORDING TO (SIMULATED) TIME.
03000
03100 ACCORDINGLY, POOMAS HAS THREE DISJOINT PARTS:
03200 1) BLIPP - BLISS LIST PROCESSING PACKAGE
03300 2) CAP - COROUTINE ACCESS PACKAGE
03400 3) QPEP - QUASI PARALLELL EXECUTION PACKAGE.
03500 IN ADDITION ARE ROUTINES FOR GENERATION OF RANDOM NUMBERS FROM
03600 VARIOUS DISTRIBUTIONS, COLLECTION OF STATISTICS, SOME SIMPLE I/O
03700 ROUTINES, AND DEBUGGING AIDS. EXEPT FOR THE DEBUGGING PACKAGE THESE
03800 CAP AND BLIPP ARE INDEPENDENT. QPEP USES BLIPP FOR SEQUENCING SET
03900 MAINTENANCE AND STORES SYSTEM INFORMATION IN THE BLIPP SYSTEM WORDS.
04000
04100 THE READER IS ASSUMED TO BE FAMILIAR WITH SIMULA.
04200 SEE: DAHL, O. J. AND NYGAARD, K:
04300 SIMULA - AN ALGOL BASED SIMULATION LANGUAGE.
04400 CACM SEPT.-66.
04500 A BRIEF SURVEY OF THE MOST IMPORTANT CONCEPTS IS GIVEN IN SECT. 6.
04600
04700 THROUGHOUT THIS DOCUMENT THE WORD PROCEDURE IS USED TO MEAN ROUTINE
04800 OR FUNCTION.
04900
05000 A SURVEY OF RECENT CHANGES TO POOMAS, AND TO THIS DOCUMENT, IS GIVEN
05100 IN SECT. 3.
05200
05300 PLEASE REPORT ERRORS AND DEFICIENCIES TO:
05400 MR. AMUND LUNDE
05500 DEPT. OF COMPUTER SCIENCE
05600 CARNEGIE-MELLON UNIVERSITY
05700 SCHENLEY PARK
05800 PITTSBURGH, PA. 15213.
00100 C O N T E N T S :
00200
00300
00400
00500 SECTION AND PAGE NUMBERING AS OBTAINED BY PRINTING WITH L COMMAND IN
00600 SOS.
00700
00800
00900 SECT
01000 2 INTRODUCTION
01100 3 TABLE OF CONTENTS
01200 4 SURVEY OF CHANGES
01300 5 MODULES AND FILES
01400 6 MINI INTRODUCTION TO QUASI PARALLELL SIMULATION
01500 7 BLIPP - THE LIST PROCESSING PACKAGE
01600 8 CAP - THE COROUTINE ACCESS PACKAGE
01700 9 QPEP - THE QUASI PARALLELL EXECUTION PACKAGE
01800 10 THE POOMAS FILE
01900 11 RANDOM NUMBER GENERATION
02000 12 COLLECTION OF STATISTICS
02100 13 DEBUGGING AIDS
02200 14 ERROR HANDLING
02300 15 AN EXAMPLE
02400 16 COMMON PITFALLS.
00100 S U R V E Y O F C H A N G E S :
00200
00300
00400
00500 SEPT. 8, 1971
00600 SMALL EXTENSION TO SUC AND PRED MACROS. (SECT. 7).
00700 CALL-FEATURE OF DEBUGGING PACKAGE NOW AVAILABLE FROM BREAKPOINTS IN
00800 DDT. (SECT. 13).
00900
01000 MAY 25, 1971.
01100 INCLUDE WILL CREATE REP'S IF NECESSARY, AND QPEP WILL SEE THROUGH
01200 THEM. MEM (FREELIST) IS NOW AT TOP OF LOWSEG, AUTOMATICALLY SET UP
01300 AND EXPANDED AS NEEDED UP TO MAXIMUM SET BY USER. I/O IS CHANGED TO
01400 USE THE BLISS I/O PACKAGE; A CONFIGURATION OF THIS JUST LARGE ENOUGH
01500 TO SUPPORT POOMAS IS PROVIDED. ROUTINES FOR STATISTICS GATHERING AND
01600 HISTOGRAM PRINTOUT ARE ADDED (SECT. 12).
01700
01800 MARCH 15, 1971:
01900 SECTION ON COMMON PITFALLS ADDED TO DOCUMENTATION.
02000
02100 FEB 22, 1971:
02200 DEBUGGING FACILITIES ADDED (INCLUDING HELP), SEE SECT. 13. BUGS AND
02300 DEFICIENCIES CORRECTED. DOCUMENTATION IMPROVED AND REORGANIZED
02400 THROUGHOUT.
02500
02600 FEB 8, 1971.
02700 BUGS AND DEFICIENCIES CORRECTED. NEW MAY NOT BE USED RECURSIVELY,
02800 RALF/RAFL INFO PRESERVED IN PROCESSES AND REMOTE ACCESSORS MODIFIED
02900 ACCORDINGLY.
03000
03100 FEB. 3, 1971:
03200 ERROR MESSAGES DESCRIBED IN SECT. 14. RELOCATABLE VERSIONS OF ALL
03300 MODULES NOW ON FILE POOLIB.REL (BUT DONT USE LIBRARY SEARCH ON IT!
03400 LOAD IT ALL.).
03500
03600 FEB 1, 1971:
03700 RANDOM NUMBER ROUTINES ADDED, MODULE RANDNO. DESCRIPTION BELOW,
03800 SECTION 11.
03900
04000 JAN 7, 1971:
04100 REVISED TO ACCOUNT FOR COROUTINE EXPRESSIONS NOW IN BLISS.
04200
04300 DEC. 1970:
04400 MAJOR REVISION OF WHOLE DOCUMENT.
00100 THE MODULES OF POOMAS
00200
00300
00400
00500 BLIPP - CONTAINS ALL OF BLIPP AND SOME ROUTINES FOR OUTPUT TO THE
00600 TTY.
00700
00800 QPEP - CONTAINS QPEP.
00900
01000 RANDNO - CONTAINS ROUTINES FOR RANDOM NUMBER GENERATION.
01100
01200 POOLOG - LOGARITHM USED BY RANDNO
01300
01400 POOEXP - EXPONENTIAL USED BY RANDNO
01500
01600 POSQRT - SQUARE ROOT USED BY RANDNO.
01700
01800 PHELP - POOMAS VERSION OF THE BLISS HELP PACKAGE.
01900
02000 POODAT - DATA COLLECTION AND OUTPUT.
02100
02200 MAIN - THE USER MODULE, CREATED FROM THE POOMAS-FILE + THE USERS
02300 PROGRAM.
02400
02500
02600
02700 THE RELEVANT FILES ARE:
02800
02900 SOURCE RELOCATABLE DOCUMENTATION
03000
03100 POOLIB.REL
03200 BLIPP.BLI BLIPP.REL
03300 QPEP.BLI QPEP.REL
03400 POOMAS.BLI POOMAS.DOC
03500 RANDNO.BLI RANDNO.REL
03600 POOLOG.MAC POOLOG.REL
03700 POOEXP.MAC POOEXP.REL
03800 POSQRT.MAC POSQRT.REL
03900 PHELP.BLI PHELP.REL
04000 POODAT.BLI POODAT.REL
04100 POOIO.REL
04200
04300 THE RELOCATABLE VERSIONS OF ALL NON I/O MODULES RESIDE ON FILE
04400 POOLIB.REL. IT IS CONSIDERABLY FASTER TO LOAD THIS THAN ALL MODULES
04500 SEPARATELY. SIMILARLY FOR POOIO.REL WHICH CONTAINS THE I/O MODULES.
04600 NOTE HOWEVER THAT THE WHOLE FILE HAS TO BE LOADED LIKE ANY OLD
04700 RELOCATABLE FILE, - LIBRARY SEARCH DOSN'T WORK. THIS IS DUE TO
04800 PROBLEMS INVOLVING BLISS, FUDGE2 AND THE LOADER.
04900
05000 THE USER WILL NORMALLY BE CONCERNED WITH POOLIB.REL, POOIO.REL,
05100 POOMAS.BLI AND POOMAS.DOC.
05200
05300 AT CMU THE MOST RECENT VERSIONS OF THESE MAY BE PULLED OFF THE DISK
05400 AREA OF N111AL10, [31500,7634] AT ANY TIME (MODULO DISK FAILURE).
00100 A MINI-INTRODUCTION TO QUASI PARALLELL SIMULATION.
00200
00300
00400
00500 CLASSES AND PROCESSES
00600
00700 BY "SYSTEM" WE MEAN THAT PORTION OF THE REAL WORLD WHICH WE WANT TO
00800 SIMULATE. MOST SYSTEMS CONSIST OF SEVERAL ACTIVITIES GOING ON IN
00900 PARALLELL AND MORE OR LESS INDEPENDENTLY, BUT INTERACTING AT CERTAIN
01000 TIMES. IN A COMPUTER IT IS NATURAL TO MODEL THIS BY CO- ROUTINES
01100 WHICH INTERACT. SOME OF THE PARALLELL ACTIVITIES IN THE SYSTEM ARE
01200 SO SIMILAR THAT THEY MAY BE DESCRIBED BY THE SAME PROGRAM BUT
01300 OPERATING ON DIFFERENT DATA. HENCE BY A "CLASS" WE MEAN A SET OF
01400 COROUTINES HAVING THE SAME PROGRAM (OR OPERATION RULE) AND DIFFERENT
01500 BUT SIMILARLY STRUCTURED DATA (ACTIVATION RECORDS). EACH PARTICULAR
01600 COROUTINE INSTANCE FROM A CLASS IS CALLED A "PROCESS" OF THAT CLASS.
01700 A PROCESS, THEN, HAS ITS OWN DATA-RECORD DESCRIBING ITS ATTRIBUTES
01800 BUT SHARES ITS PROGRAM WITH ALL PROCESSES OF THE SAME CLASS. A
01900 PROCESS IS IDENTIFIED BY ITS "PROCESS DESCRIPTOR", WHICH IS THE VALUE
02000 OF THE CREATING EXPRESSION AND CONSISTS OF THE STACK BASE OF THE
02100 PROCESS + POSSIBLY OTHER INFORMATION DESCRIBED ELSEWHERE.
02200
02300 IF OUR SYSTEM CONSISTS OF MEN AND MACHINES, SAY, IT MAY BE REASONABLE
02400 TO HAVE TWO CLASSES, MAN AND MACHINE, EACH REPRESENTED BY A ROUTINE
02500 DECLARATION. A MAN-PROCESS (I.E. A COROUTINE INSTANCE OF THE MAN
02600 ROUTINE) MIGHT BE CREATED CORRESPONDING TO A MAN REPORTING TO WORK IN
02700 THE SYSTEM, IT MIGHT BE DESTROYED WHEN THE MAN IN THE SYSTEM GOES
02800 HOME FOR DINNER. SIMILARLY MACHINE-PROCESSES COULD BE CREATED AND
02900 DESTROYED DYNAMICALLY.
03000
03100
03200 EVENTS
03300
03400 WE FURTHER ASSUME THAT THE SYSTEM CAN BE DESCRIBED BY INSTANTANEOUS
03500 ACTIONS BY THE PROCESSES. SUCH AN ACTION IS CALLED AN "EVENT".
03600 SIMULATED TIME FLOWS BETWEEN EVENTS, NOT DURING EVENTS. TO SIMULATE
03700 CONTINUITY EVENTS HAVE TO BE SPACED CLOSELY IN TIME. THIS IS
03800 ANALOGOUS TO SOLVING DIFFERENTIAL EQUATIONS ON A DIGITAL DEVICE. AN
03900 EVENT CAN ONLY END WHEN THE PROCESS CONCERNED EXECUTES A STATEMENT
04000 THAT EXPLISITLY OR IMPLISITLY ENDS IT. IMPLISITLY ENDING AN EVENT
04100 COULD BE BY SCHEDULING ANOTHER EVENT AHEAD OF IT (AT THE SAME TIME)
04200 OR EXECUTING A RETURN FROM THE OUTMOST PROCEDURE OF THE PROCESS. AN
04300 EVENT CAN NEVER END AS A RESULT OF ANY KIND OF INTERRUPT FROM OTHER
04400 PROCESSES. THIS IS A CONSEQUENCE OF OUR ASSUMPTION THAT EVENTS TAKE
04500 NO TIME.
04600
04700 IN OUR SYSTEM ABOVE, THE EVENTS FOR A MAN PROCESS MIGHT BE: 1)
04800 ARRIVING AT WORK, 2) WALKING UP TO MACHINE, 3) LOADING MATERIAL INTO
04900 MACHINE, 4) REMOVING PRODUCT FROM MACHINE, 5) LEAVING WORK.
05000 PRESUMABLY 3 AND 4 WOULD BE ENCLOSED BY A LOOP.
05100
05200
05300 STRUCTURE OF OPERATION RULE, REACTIVATION POINT.
05400
05500 THE PROGRAM FOR A CLASS WILL CONSIST OF STATEMENTS DESCRIBING EACH
05600 EVENT, AND SEQUENCING STATEMENTS WHICH END EVENTS AND SCHEDULE
05700 OTHERS. WHEN AN EVENT FOR A PROCESS ENDS, ITS NEXT EVENT WILL START
05800 EXECUTING THE CODE IMMEDIATELY FOLLOWING THE SEQUENCING STATEMENT
05900 THAT ENDED THE FORMER EVENT. THIS POINT IN THE CODE IS CALLED THE
06000 "REACTIVATION POINT" OF THE PROCESS, AND ITS ADDRESS IS STORED IN THE
06100 ACTIVATION RECORD OF THE PROCESS. WHEN A PROCESS EXECUTES A RETURN
06200 FROM ITS OUTERMOST PROCEDURE, IT WILL LOSE ITS REACTIVATION POINT AND
06300 CAN NOT BE REVIVED.
06400
06500
06600 SCHEDULING
06700
06800 A PROCESS MAY, BY EXECUTING APPROPRIATE SCEDULING STATEMENTS,
06900 INDICATE THAT IT, OR SOME OTHER PROCESS, WILL HAVE ITS NEXT EVENT AT
07000 SOME GIVEN TIME OR BEFORE OR AFTER SOME GIVEN EVENT. IT MAY ALSO
07100 CANCEL ANY EVENT PREVIOUSLY SCHEDULED, INCLUDING ITS OWN CURRENT
07200 EVENT. IF A PROCESS SCHEDULES ITSELF, ITS CURRENT EVENT WILL END
07300 IMMEDIATELY. A PROCESS HAS AT MOST ONE EVENT SCHEDULED FOR IT AT ANY
07400 ONE TIME, AND IF THERE IS ONE THE PROCESS IS SAID TO BE SLATED. THE
07500 CURRENT PROCESS IS ALWAYS SLATED.
07600
07700 IT IS SEEN THAT THE IDENTITY OF THE NEXT EVENT OF A PROCESS IS
07800 DETERMINED BY THAT PROCESS ITSELF, I.E. THE REACTIVATION POINT IS
07900 DETERMINED BY THE OPERATION RULE OF THE PROCESS. HOWEVER, THE TIME
08000 WHEN THIS EVENT WILL OCCUR CAN BE DETERMINED BY ANY PROCESS THAT IS
08100 ABLE TO REFERENCE THE PROCESS (SCHEDULE IT).
08200
08300
08400 EVENTNOTICES AND SEQUENCING SET
08500
08600 SLATED EVENTS ARE REPRESENTED BY EVENTNOTICES, WHICH ARE MEMBERS OF A
08700 LINEAR LIST CALLED THE SEQUENCING SET OR SQS. THE NOTICES IN SQS ARE
08800 ORDERED BY TIME, WHICH IS A FLOATING POINT VALUE. THE FIRST NOTICE
08900 IN SQS REPRESENTS THE CURRENT EVENT. IT IS NECESSARY TO HAVE THE
09000 CURRENT EVENT REPRESENTED IN SQS, SINCE IT MAY SCHEDULE OTHER EVENTS
09100 IN FRONT OF ITSELF AT THE SAME TIME. TIME MAY, HOWEVER, NOT
09200 DECREASE. EACH EVENTNOTICE ALSO CONTAINS A PROCESS DESCRIPTOR FOR THE
09300 PROCESS THAT WILL EXECUTE THE EVENT. IT IS SEEN THAT SEQUENCING
09400 CONSISTS OF CHANGING THE SQS, SCHEDULING OF INTRODUCING OR MOVING
09500 EVENTNOTICES IN SQS.
09600
09700
09800 SIMULTANEITY
09900
10000 THERE MAY BE MANY EVENTS TAKING PLACE AT THE SAME SIMULATED TIME, THE
10100 SCHEDULING STATEMENTS HAVE PARAMETERS TO CONTROL WHETHER EVENTS ARE
10200 SCHEDULED FIRST OR LAST AMONG THE ALREADY SLATED EVENTS AT THAT TIME,
10300 AND ALSO PARAMETERS TO SCHEDULE AN EVENT IMMEDIATELY BEFORE OR AFTER
10400 ANY GIVEN SLATED EVENT, AT THE SAME SIMULATED TIME AS THE GIVEN
10500 EVENT. THIS COMPLETELY DETERMINES THE SEQUENCE OF EVENTS.
10600
10700
10800 THE MAIN PROGRAM
10900
11000 INITIALLY THE MAIN PROGRAM IS THE ACTIVE AND ONLY PROCESS, AND
11100 INITQPEP WILL PUT AN EVENTNOTICE FOR IT, WITH TIME REFERENCE 0.0, IN
11200 THE SQS. IT IS THE RESPONSIBILITY OF THE MAIN PROGRAM TO START THE
11300 SIMULATION BY CREATING AND SCHEDULING OTHER PROCESSES.
11400
11500 USUALLY THE MAIN PROGRAM WILL REGAIN CONTROL, EITHER BY RESCHEDULING
11600 ITSELF OR BY BEING RESCHEDULED FROM SOME OTHER PROCESS, TO OUTPUT
11700 STATISTICS AND FINISH THE SIMULATION OR START ANOTHER ONE.
11800
11900 A SMALL EXAMPLE IS GIVEN IN SECT. 15.
00100 B L I P P
00200
00300
00400
00500 LISTS AND OBJECTS:
00600
00700 LISTS ARE DOUBLY LINKED, CIRCULAR AND WITH A DESIGNATED HEAD. THE
00800 MEMBERS, INCLUDING THE HEAD, ARE CALLED OBJECTS. OBJECTS ARE MEMBERS
00900 OF AT MOST ONE LIST. TO MAINTAIN UNIFORM REFERENCES TO OBJECTS
01000 THROUGHOUT, ALL OBJECTS ARE REFERENCED BY THEIR WORD 0 WHICH IS
01100 ACTUALLY THE FOURTH WORD. THE ADDRESS OF WORD 0 IS CALLED THE
01200 ADDRESS OF THE OBJECT. THIS HOLDS EVEN FOR 2 AND 3 WORD OBJECTS, AND
01300 SHOULD CAUSE NO CONFUSION AS LONG AS ONE KEEPS WITHIN THE POOMAS
01400 ROUTINES AND MACROS. WORDS -3, -2, AND -1 ARE CALLED THE SYSTEM
01500 WORDS, WORDS 0 THROUGH SIZE-4 ARE CALLED THE USER WORDS OF THE
01600 OBJECT. IF QPEP IS NOT USED, THE USER MAY USE WORD -1. INFORMATION
01700 RELEVANT TO BLIPP IS KEPT IN WORDS -3 AND -2 OF EACH OBJECT. OBJECTS
01800 MAY CONTAIN ACTIVATION RECORDS FOR COROUTINES. IN THAT CASE WORD 0
01900 IS THE STACK BASE OF THE COROUTINE. WORD -1 IS RESERVED FOR QPEP.
02000
02100
02200 FREE-LIST MANAGEMENT:
02300
02400 SPACE FOR OBJECTS IS TAKEN FROM AN AREA MEM OF SIZE .MEMSIZE.
02500 INITIALLY MEM WILL CONSIST OF THE UNUSED SPACE AT THE HIGH END OF
02600 LOWSEG. A FREE - LIST IS MAINTAINED IN MEM. THE USER MAY PUT OBJECTS
02700 ON THE FREE - LIST THAT WERE NOT PREVIOUSLY WITHIN MEM, AND BLIPP
02800 WILL, WHEN NEEDED, REQUEST ADDITIONAL MEMORY FROM THE OPERATING
02900 SYSTEM THAT NEED NOT BE CONTIGUOUS WITH MEM. IN PARTICULAR I/O
03000 BUFFERS OBTAINED BY USUAL METHODS MAY BE INTERSPERSED BETWEEN PIECES
03100 OF MEM. MEM WILL NOT BE EXPANDED BEYOND THE SIZE .MAXMEM, EXEPT
03200 POSSIBLY FOR THE INITIAL ALLOCATION. IF THE PROGRAM IS RESTARTED BY
03300 THE $G COMMAND TO DDT, MEMORY SIZE WILL NOT BE REDUCED. CONTIGUOUS
03400 OBJECTS ON THE FREE - LIST ARE MERGED. IT IS THE RESPONSIBILITY OF
03500 THE USER TO RETURN OBJECTS TO THE FREELIST WHEN HE NO LONGER NEEDS
03600 THEM. THE FREE - LIST IS ORGANIZED AS ANY OTHER BLIPP LIST AND IS
03700 MAINTAINED USING NORMAL BLIPP ROUTINES.
03800
03900
04000 MULTIPLE LIST MEMBERSHIP:
04100
04200 IF IT IS NECCESSARY THAT AN OBJECT BE A MEMBER OF MORE THAN ONE LIST,
04300 REPRESENTATIVES (REP-OBJECTS) MUST BE USED. INCLUDE WILL CREATE A
04400 REP WHENEVER THE OBJECT TO BE INCLUDED IS ALREADY A LIST MEMBER.
04500 OTHERWISE IT IS UP TO THE USER TO CREATE REP'S. NO BLIPP ROUTINES,
04600 BUT ALL QPEP ROUTINES THAT EXPECT A PROCESS AS PARAMETER, WILL SEE
04700 THROUGH REP'S.
04800
04900
05000
05100 OBJECT STRUCTURE
05200
05300
05400 _______________
05500 -3 ^ PRED ^ SUC ^ PRED AND SUC CONTAIN THE ADDRESSES OF THE PREDE-
05600 -2 ^CLASS ^ SIZE ^ CESSOR AND SUCCESSOR IN THE LIST, IF THE OBJECT
05700 -1 ^ ^ IS NOT A MEMBER OF ANY LIST THEY CONTAIN NONE (A
05800 --------------- MACRO). SIZE IS THE SIZE OF THE OBJECT, INCLU-
05900 0 ^ ^ DING SYSTEM WORDS. CLASS IS USED BY BLIPP AND
06000 ^ ^ USERS TO CLASSIFY OBJECTS.
06100 ^ ^
06200 ---------------
06300
06400
06500 THE FOLLOWING VALUES OF CLASS ARE RECOGNICED BY BLIPP:
06600
06700 .CLASS=FREECLASS (0)
06800 OBJECT IS MEMBER OF FREE - LIST.
06900
07000 .CLASS=HEADCLASS (-1)
07100 OBJECT IS A LIST HEAD. IF THE LIST IS EMPTY THE PRED AND SUC POINT
07200 TO THE HEAD ITSELF. SIZE IS 2.
07300
07400 .CLASS=REPCLASS (-2)
07500 OBJECT IS A REPRESENTATIVE. OBJREF (IN WORD -1) CONTAINS ADDRESS OF
07600 OBJECT REPRESENTED. SIZE IS 3.
07700
07800 .CLASS=100 (DECIMAL)
07900 DEFAULT VALUE ASSIGNED BY GETSPACE.
08000
08100
08200 OTHER CLASSES:
08300
08400 QPEP USES THE FOLLOWING CONVENTIONS:
08500
08600 .CLASS=EVNOTCLASS (-3)
08700 OBJECT IS EVENTNOTICE, AND A MEMBER OF THE SEQUENCING SET (SQS).
08800 SIZE IS 4. WORD -1 CONTAINS THE REFERENCE (SEE CAP) TO THE PROCESS
08900 TO BE ACTIVATED, WORD 0 CONTAINS THE SIMULATED TIME WHEN ACTIVATION
09000 IS TO OCCUR.
09100
09200 OBJECT IS A PROCESS:
09300 .CLASS IS THE ADDRESS OF THE FIRST INSTRUCTION OF THE PROCEDURE FOR
09400 THE PROCESS. QPEP CHECKS FOR CORRECTNESS BY THE ROUTINE ISPROCESS
09500 (SEE BELOW).
09600
09700
09800 SUBLISTS MAY BE IMPLEMENTED USING REP'S.
09900
10000 THE CLASS NAMES USED ABOVE ARE DEFINED AS MACROS.
10100
10200
10300
10400 THE DECLARATION 'STRUCTURE OBJECT'
10500
10600
10700 IF X CONTAINS THE ADDRESS OF AN OBJECT OR A PROCCESS REFERENCE (CAP),
10800 AND THE DECLARATION
10900 MAP OBJECT X;
11000 IS VALID, THE MACROS AND ROUTINES OF BLIPP (AND QPEP) MAY BE USED TO
11100 MANIPULATE THE OBJECT AT .X.
11200
11300 THE FOLLOWING MACROS SUPPLY POINTERS TO THE VARIOUS STANDARD FIELDS
11400 OF AN OBJECT:
11500
11600 PRED(E) = (E[-3]<18,18>)$, ! PREDECESSOR FIELD.
11700 SUC(E) = (E[-3]<0,18>)$, ! SUCCESSOR FIELD.
11800 CLASS(E) = (E[-2]<18,18>)$, ! CLASS FIELD.
11900 SIZE(E) = (E[-2]<0,18>)$, ! SIZE FIELD.
12000 POINTERS(E) = (E[-3])$, ! PRED AND SUC COMBINED.
12100 OBJREF(E) = (E[-1])$; ! OBJECT REFERENCE FIELD.
12200
12300 NOTE: THE ACTUAL PARAMETER TO THESE MACROS SHOULD EITHER BE AN
12400 IDENTIFIER MAPPED TO OBJECT, OR AN EXPRESSION WHICH EVALUATES TO AN
12500 OBJECT ADDRESS. SUCH EXPRESSIONS MUST BE ENCLOSED IN PARENTHESIS.
12600 I.E.: IF OB IS MAPPED TO OBJECT THE FOLLOWING IS LEGAL:
12700 OB _ .SUC((.PRED(OB)));
12800
12900
13000
13100 FOLLOWING IS A DESCRIPTION OF THE ROUTINES OF BLIPP.
13200
13300
13400
13500 INITIALIZATION OF BLIPP:
13600
13700 INITBLIPP()
13800 WILL INITIALIZE MEM AT THE TOP OF LOWSEGMENT (SEE INITMEM), AND ALSO
13900 SOME BLIPP VARIABLES INCLUDING MEMOB AND MEMSIZE.
14000 VALUE: .MEMSIZE-2.
14100
14200
14300
14400 MEMORY MANAGEMENT:
14500
14600
14700 INITMEM()
14800 THIS ROUTINE ASSUMES THAT MEM IS CONTIGUOUS FROM .MEMOB-3 TO
14900 .MEMOB-3+.MEMSIZE IT WILL CLEAR ALL WORDS OF MEM AND SET UP A
15000 FREELIST WITH ITS HEAD AT .MEMOB. THIS ROUTINE SHOULD BE USED TO
15100 REINITIALIZE THE OLD MEM, SINCE INITBLIPP WOULD OBTAIN COMPLETELY NEW
15200 SPACE FROM THE MONITOR. BEWARE HOWEVER: ALL I/O BUFFERS MUST BE
15300 INITIALIZED BEFORE THE INITIAL CALL TO INITMEM OR ELSE . . .! THE
15400 USER DOES THIS BY DECLARING A GLOBAL ROUTINE INITIO, WHICH DOES THIS,
15500 IN HIS PROGRAM. SEE PARAGRAPH ON I/O BELOW.
15600 VALUE: .MEMSIZE-2.
15700
15800 GETSPACE(WDS)
15900 WILL FIND SPACE FOR AN OBJECT OF SIZE .WDS FROM THE FREE LIST. THE
16000 USER WORDS ARE CLEARED TO ZEROES, SUC AND PRED ARE SET TO NONE, CLASS
16100 IS SET TO 100 (DECIMAL).
16200 VALUE: 0 IF SPACE NOT AVAILABLE, OTHERWISE ADDRESS OF OBJECT.
16300
16400 RELEASESPACE(OBJ)
16500 WILL RETURN THE SPACE OF THE OBJECT AT .OBJ TO THE FREE LIST, MERGING
16600 IT WITH NEIGHBOURING FREE SPACE IF POSSIBLE.
16700 VALUE: 0 IF ERRORS, OTHERWISE 1.
16800
16900 FOR REASONS OF SECURITY, POOMAS USERS SHOULD PREFER NEW, MAKELIST,
17000 MAKEREP OR POSSIBLY MAKEOBJ TO CREATE OBJECTS, AND RELEASELIST,
17100 RELEASEMEMBERS OR KILL TO RETURN OBJECTS TO FREELIST.
17200
17300
17400
17500 OBJECT AND SET CREATION:
17600
17700 THESE ROUTINES ARE USED TO CREATE OBJECTS OF STANDARD AND
17800 USER-INVENTED KINDS.
17900
18000 MAKELIST()
18100 WILL CREATE A LIST HEAD.
18200 VALUE: 0 IF ERRORS, OTHERWISE ADDRESS OF HEAD.
18300
18400 MAKEOBJ(WDS,TYPE)
18500 CREATES AN OBJECT OF .WDS USER WORDS AND CLASS .TYPE.
18600 VALUE: 0 IF ERRORS, OTHERWISE ADDRESS OF OBJECT.
18700
18800 MAKEREP(OBJ)
18900 CREATES A REPRESENTATIVE OF OBJECT AT .OBJ.
19000 VALUE: 0 IF ERRORS, OTHERWISE ADDRESS OF REP.
19100
19200
19300
19400 REMOVAL FROM AND DESTRUCTION OF LISTS.
19500
19600 REMOVE(X)
19700 REMOVES OBJECT AT .X FROM WHATEVER LIST IT WAS A MEMBER, UNLESS IT IS
19800 A LIST HEADER.
19900 VALUE: 0 IF .X IS NONE OR A HEADER, OTHERWISE .X.
20000
20100 CLEARLIST(S)
20200 REMOVES ALL MEMBERS OF LIST AT .S.
20300 NOTE:
20400 SHOULD BE USED WITH CAUTION SINCE NON-REFERENCABLE OBJECTS ARE NOT
20500 RETURNABLE TO THE FREE-LIST.
20600 VALUE: 0 IF ERRORS, OTHERWISE .S.
20700
20800 RELEASELIST(S)
20900 WILL REMOVE ALL MEMBERS OF LIST AT .S INCLUDING THE HEAD AND RELEASE
21000 THEIR SPACE TO THE FREE LIST.
21100 VALUE: 0 IF ERRORS, OTHERWISE 1.
21200
21300 RELEASEMEMBERS(S)
21400 AS RELEASELIST BUT DOES NOT RELEASE LIST HEAD.
21500 VALUE: 0 IF ERRORS, OTHERWISE .S.
21600
21700
21800
21900 INSERTION INTO LISTS:
22000
22100 IF OBJECT AT .X IS ALREADY MEMBER OF SOME LIST IT WILL BE REMOVED
22200 FROM THAT LIST, EXEPT FOR INCLUDE, WHICH WILL CREATE A REP. NEXT IT
22300 WILL BE INSERTED INTO ANOTHER LIST AS FOR THE SPECIFIC FUNCTION
22400 INVOLVED. IN CASE OF ERROR .X IS NOT REMOVED.
22500
22600 INSERTAFTER(X,Y)
22700 INSERTS .X AFTER .Y IN THE LIST WHERE .Y IS A MEMBER.
22800 VALUE: 0 IF ERRORS, OTHERWISE .X.
22900
23000 INSERTBEFORE(X,Y)
23100 AS INSERTAFTER BUT INSERTS .X BEFORE .Y.
23200
23300 INCLUDE(X,S)
23400 .X, OR A REPRESENTATIVE OF .X, IS INSERTED AS THE LAST MEMBER OF THE
23500 LIST .S.
23600 VALUE: 0 IF ERRORS, OTHERWISE .X.
23700
23800 REPLACE(OLD,NEW)
23900 .NEW IS INSERTED INSTEAD OF .OLD IN THE LIST WHERE .OLD WAS A MEMBER.
24000 NEITHER OR BOTH ARGUMENTS SHOULD BE HEADS.
24100 VALUE: 0 IF ERRORS, OTHERWISE .OLD
24200
24300
24400
24500 ACCESSING LIST MEMBERS:
24600
24700 FIRST(S)
24800 FINDS FIRST MEMBER OF LIST AT .S.
24900 VALUE: 0 IF .S IS NOT A LIST, NONE IF IT IS EMPTY, OTHERWISE ADDRESS
25000 OF FIRST MEMBER.
25100
25200 LAST(S)
25300 ANALOGOUS TO FIRST.
25400
25500 FIND(S,C,I,X)
25600 ATTEMPTS TO FIND A MEMBER OF THE LIST AT .S, WHICH IS OF CLASS .C,
25700 WHOSE .I'TH WORD CONTAINS .X.
25800 VALUE: 0 IF .S IS NOT A LIST, NONE IF UNSUCCESSFUL, OTHERWISE ADDRESS
25900 OF MEMBER.
26000
26100 MAPLIST(S,F)
26200 APPLIES THE FUNCTION OR ROUTINE .F TO ALL MEMBERS OF THE LIST AT .S
26300 EXEPT THE HEAD. (.F SHOULD BE THE ADDRESS OF THE ENTRYPOINT). .F
26400 TAKES ONE ARGUMENT, THE CURRENT OBJECT TO WHICH IT SHOULD BE APPLIED.
26500 MAPLIST HAS A POINTER TO THE NEXT MEMBER OF THE LIST, HENCE .F MAY
26600 REMOVE ITS ARGUMENT IF DESIRED, BUT NOT ITS SUCCESSOR. VALUE OF F
26700 SHOULD BE NONZERO UNLESS ERRORS OCCUR. IF 0 IS RETURNED BY F,
26800 MAPLIST WILL EXECUTE A RETURN(0) IMMEDIATELY.
26900 VALUE: 0 IF ERRORS, OTHERWISE 1.
27000
27100
27200
27300 MISCELLANEOUS ROUTINES:
27400
27500 ISROFUN(P)
27600 CHECKS WHETHER .P IS THE ADDRESS (ENTRYPOINT) OF A PROCEDURE. NOTE
27700 THAT ALL PROCEDURES WILL PASS THE TEST, PROVIDED THE PROGRAM IS
27800 COMPILED USING THE INSPECT OPTION, BUT CERTAIN DATA AREAS MAY BE
27900 INDISTINGUISHABLE FROM A 0-PARAMETER, 0-LOCALS, 0-REGISTERS- SAVED
28000 ROUTINE. HENCE SOME SUCH AREAS WILL PASS THE TEST.
28100 VALUE: 0 OR 1, 3 IF IN DOUBT.
28200
28300 EMPTY(S)
28400 VALUE: 1 IF LIST AT .S IS EMPTY, 0 IF IT IS NON-EMPTY
28500 OR -2 IF S IS NOT A HEAD.
28600
28700 CARDINAL(S)
28800 VALUE: -1 IF OBJECT AT .S IS NOT A LIST HEAD, OTHERWISE THE # OF
28900 MEMBERS DISTINCT FROM THE HEAD.
29000
29100
29200
29300 ERROR HANDLING:
29400
29500 BLIPPERROR(MSG)
29600 BLIPP WILL CHECK FOR INCONSISTENCIES OF PARAMETERS AND SIMILAR ERROR
29700 CONDITIONS. WHEN AN ERROR IS DETECTED THE ROUTINE BLIPPERROR IS
29800 CALLED WITH A PARAMETER DESCRIBING THE ERROR. BLIPPERROR WILL
29900 DECREASE ERRCOUNT, AND WHEN THIS REACHES 0 EXECUTION WILL BE ABORTED.
30000 THE ERROR INDICATOR IS STORED IN BERRMS. IN ANY CASE BLIPPERROR WILL
30100 CALL DDTBREAK.
30200 VALUE: .BLIPPERRCOUNT.
30300
30400 DDTBREAK()
30500 A DUMMY ROUTINE USED AS A BREAKPOINT LOCATION TO FORCE PROGRAM INTO
30600 DDT AT PREDETERMINED LOCATIONS. ONLY ONE BREAKPOINT, AT 'DDTBREAK',
30700 NEED BE SET IN DDT. SEE ALSO TRACEBREAK IN QPEP.
30800 VALUE: 0.
30900
31000
31100
31200 INPUT AND OUTPUT:
31300
31400 POOMAS DOES ITS I/O THROUGH THE BLISS I/O PACKAGE, AND A SMALL
31500 CONFIGURATION OF THIS, WHICH WILL JUST SUPPORT THE I/O IN POOMAS IS
31600 COMPOSED OF: BLIO, SCAN0, SCNR, QTAB1, TRACE1, NUMIO0, ERROR0,
31700 ERRTB4, FLOUT, DFLT, TBL. THIS IS PROVIDED ON THE FILE POOIO.REL, TO
31800 SAVE LOAD TIME. THE USER IS FREE TO USE HIS OWN CONFIGURATION AS LONG
31900 AS IT IS A SUPERSET OF THE ABOVE.
32000
32100 INITIO()
32200 THIS ROUTINE MUST BE DECLARED AS A GLOBAL ROUTINE BY ALL USERS WHO
32300 HAVE POOMAS.BLI AS A PREFIX TO THEIR PROGRAM. (SEE SECT. 10). IF
32400 ALL FILE-INITIALIZATIONS, INCLUDING AN INITIAL READ OR WRITE ON EACH
32500 FILE, ARE DONE IN INITIO, THE BUFFERS WILL ALL BE SET UP BEFORE MEM
32600 IS INITIALIZED, AND MEM WILL BE CONTIGUOUS AND ABOVE THE BUFFERS IN
32700 LOWSEG. HENCE THE BUFFERS WILL BE SAVED ACROSS INITMEM() CALLS (BUT
32800 OF COURSE NOT ACROSS $G'S IN DDT). IF IT IS NOT DESIRED TO USE
32900 INITMEM, OR IF ONLY CHANNEL 0 IS USED, INITIO MAY BE DUMMY, BUT IT
33000 MUST BE PRESENT.
33100
33200
33300 THE FOLLOWING MACROS AND ROUTINES SERVE TO INTERFACE PREVIOUS I/O IN
33400 POOMAS TO BLIO.
33500
33600
33700 TYPE(WORD,LF) - MACRO -
33800 TYPES UP TO 5 CHARACTERS AT THE TTY. WORD SHOULD BE A LEFTADJUSTED
33900 STRING OF AT MOST 5 CHARACTERS, LF SHOULD BE ODD IF A CR,LF IS
34000 DESIRED FOLLOWING THE STRING.
34100 VALUE: 0.
34200
34300 TYPDEC(N,LF) - MACRO -
34400 OUTPUTS N AS A DECIMAL INTEGER, LEADING ZEROES SUPPRESSED, USING AS
34500 LITTLE SPACE AS POSSIBLE. IF LF IS ODD, NUMBER WILL BE FOLLOWED BY
34600 CR,LF.
34700 VALUE: 0.
34800
34900 TYPFLT(N,LF) - MACRO -
35000 OUTPUTS N AS A DECIMAL FLOATING POINT NUMBER, LEADING ZEROES
35100 SUPPRESSED, USING AS LITTLE SPACE AS POSSIBLE. IF LF IS ODD, NUMBER
35200 WILL BE FOLLOWED BY CR,LF.
35300 VALUE: 0.
35400
35500 TYPOCT(N,LF) - ROUTINE -
35600 TYPES .N AS AN UNSIGNED OCTAL NUMBER, FOLLOWED BY CR,LF IFF .LF IS
35700 ODD. LEADING ZEROES ARE SUPPRESSED.
35800 VALUE: 0.
35900
36000 TYPLIS(L) - ROUTINE -
36100 THIS IS A USEFUL DEBUGGING AID, PARTICULARLY IN LIMP MODE (SEE SECT
36200 13). IT TYPES THE FIRST 4 WORDS (FEWER IF OBJECT IS SMALLER) OF EACH
36300 MEMBER OF THE LIST AT .L, INCLUDING THE HEAD. EACH OBJECT ON A
36400 SEPARATE LINE, PRECEEDED BY ITS ADDRESS. FORMAT AS FOR TYPOCT.
36500 VALUE: 0.
00100 C O R O U T I N E A C C E S S
00200
00300
00400
00500 TO USE THE COROUTINE ACCESS FACILITIES, PROGRAMS SHOULD BE COMPILED
00600 WITH THE /I SWITCH (OR EQUIVALENT). THE INSPECT AND RSAVE OPTIONS ARE
00700 PROVIDED IN ALL MODULE-HEADS IN POOMAS.
00800
00900
01000 THE VALUE OF A CREATE-EXPRESSION IS A PROCESS DESCRIPTOR HAVING THE
01100 FOLLOWING FORMAT:
01200
01300 --------- --------- ------------------
01400 ^ RAFL ^ RALF ^ BASE ^
01500 --------- --------- ------------------
01600 0 7 8 17 18 35
01700
01800 WHERE:
01900 BASE = STACK BASE ADDRESS FOR CREATED PROCESS,
02000 RAFL = RELATIVE ADDRESS OF FIRST LOCAL,
02100 RALF = RELATIVE ADDRESS OF LAST PARAMETER.
02200 (THE TWO LATTER ARE RELATIVE TO BASE.)
02300 RALF OR RAFL OR BOTH MAY BE ZERO IF THERE ARE NO ACTUALS OR LOCALS.
02400
02500 TO ACCESS A PARAMETER OR LOCAL IN A PARALLELL PROCESS ONE HAS TO KNOW
02600 ITS ADDRESS RELATIVE TO THE LAST PARAMETER OR THE FIRST LOCAL IN THE
02700 MAIN PROCEDURE OF THE PROCESS. FOR THE MAIN PROCEDURE ITSELF THIS IS
02800 EASILY OBTAINED BY COUNTING AT THE DECLARATION SITE. FOR INNER
02900 PROCEDURES OR BLOCKS IT MAY BE CALCULATED USING THE OBJECT SIZE
03000 OBTAINED FROM THE WORD PRECEDING THE ENTRYPOINT TO EACH PROCEDURE.
03100
03200
03300 EXAMPLE:
03400
03500 ASSUME WE HAVE CREATED A COROUTINE INSTANCE OF
03600
03700 ROUTINE P(F2,F1,F0) =
03800 BEGIN LOCAL L0,L1[2],L3; . . . END;
03900
04000 WE THEN WILL FIND
04100 F2 AT BASE + RALF - 2,
04200 F1 AT BASE + RALF - 1,
04300 L3 AT BASE + RAFL + 3,
04400 AND SO ON.
04500
04600
04700 THE NEW-MACRO WILL STORE THE RAFL RALF OBTAINED FROM THE CREATE IN
04800 THE RARA FIELD OF THE CREATED PROCESS. THIS WILL PRESERVE THESE
04900 VALUES EVEN IF THE PROCESS IS RETRIEVED FROM A LIST. FOR PROCESSES
05000 CREATED BY NEW, REMOTE ACCESS IS SIMPLIFIED BY THE REMOTE - MACROS
05100 BELOW, WHICH DELIVER THE ADDRESSES OF THE I'TH LOCAL OR I'TH FORMAL
05200 RESPECTIVELY IN A PROCESS. FURTHERMORE P MAY BE CLOSED TO ACCESS
05300 FROM OUTSIDE BY STORING 0 IN ITS RARA FIELD. THE REMOTE-MACROS WILL
05400 THEN ACCESS THE BASE-LOCATION OF THE CURRENTLY ACTIVE PROCESS, WHICH
05500 IS SAFE BUT MEANINGLESS. THE MACRO CLOSEPROC ACCOMPLISHES THE
05600 CLOSING. IT IS THE RESPONSIBILITY OF THE USER TO INITIALIZE THE
05700 RARA-FIELD OF THE MAIN PROGRAM SHOULD THIS BE NEEDED. THE FIRST
05800 PARAMETER TO REMOTEFML OR REMOTELCL SHOULD EVALUATE TO THE ADDRESS OF
05900 THE PROCESS ACCESSED. THE SECOND SHOULD EVALUATE TO THE ADDRESS OF
06000 THE LOCAL OR FORMAL DESIRED, RELATIVE TO THE FIRST LOCAL (HENCE NOT <
06100 0) OR THE LAST FORMAL (HENCE NOT > 0) FOR REMOTELCL OR REMOTEFML
06200 RESPECTIVELY. THE VALUES OF THESE MACROS ARE ADDRESSES, POINTER
06300 PARAMETERS IN <> AND CONTENTS OPERATORS MUST BE SUPPLIED BY THE USER
06400 AS NEEDED. THE PARAMETER TO THE CLOSEPROC MACRO SHOULD BE AN
06500 IDENTIFIER MAPPED TO OBJECT.
06600
06700
06800 NEW(P,S)
06900 THE 2 PARAMETERS TO THIS MACRO SPECIFY A ROUTINE WITH ITS PARAMETERS
07000 AND THE STACK-SIZE (EXCLUDING STATE AREA) FOR THE PROCESS TO BE
07100 CREATED. P SHOULD SYNTACTICALLY TAKE THE FORM OF A PROCEDURE CALL, S
07200 SHOULD EVALUATE TO A NUMBER. A COROUTINE INSTANCE OF P IS CREATED.
07300 IF THIS PROCESS EXECUTES A RETURN OUT OF ITS OUTMOST PROCEDURE IT
07400 WILL BE TERMINATED.
07500 VALUE: PROCESS DESCRIPTOR.
07600
07700 REMOTELCL(P,I) =
07800 (IF .(P)[-1]<RAFL> EQL 0 THEN (BLIPPERROR(31); .BREG)
07900 ELSE .(P)[-1]<RAFL>+P<BASE>+I)$,
08000
08100 REMOTEFML(P,I) =
08200 (IF .(P)[-1]<RALF> EQL 0 THEN (BLIPPERROR(31); .BREG)
08300 ELSE .(P)[-1]<RALF>+P<BASE>+I)$,
08400
08500 CLOSEPROC(P) =
08600 (RARA(P) _ 0)$;
08700
08800
08900 EXAMPLE:
09000
09100 LET PROC CONTAIN A PROCESS DESCRIPTOR FOR A COROUTINE INSTANCE OF
09200 ROUTINE P. AFTER EXECUTING:
09300 I _ -3;
09400 REMOTELCL(.PROC,2)<0,36> _ 144;
09500 REMOTEFML(.PROC,.I)<0,36> _ -.I*4*12;
09600 WE WILL HAVE
09700 .REMOTELCL(.PROC,-.I-1)<0,36> EQL .REMOTEFML(.PROC,.I)<0,36>
09800
00100 Q P E P
00200
00300
00400
00500 PROCESSES
00600
00700
00800 _____________
00900 -3 ^PRED ^ SUC ^ CLASS CONTAINS THE ADDRESS OF THE PROCEDURE OF THE
01000 -2 ^CLASS^SIZE ^ PROCESS.
01100 -1 ^ RARA^EVNOT^
01200 ------------ EVNOT CONTAINS THE ADDRESS OF THE EVENTNOTICE
01300 0 ^ ^ REFERENCING THIS PROCESS, OR NONE IF THERE IS NO
01400 ^ ^ SUCH EVENTNOTICE.
01500 ^ ^ RARA CONTAINS THE RAFL-RALF FIELD OF THE VALUE
01600 ------------- OF THE CREATE THAT CREATED THE OBJECT.
01700
01800 A MACRO NEW, DESCRIBED IN THE CAP SECTION, IS USED TO CREATE
01900 PROCESSES SO THAT THE ABOVE FIELDS ARE SET, AND SO THAT THE PROCESS
02000 IS TERMINATED SHOULD ITS PROCEDURE RETURN.
02100
02200
02300 EVENTNOTICES
02400
02500 _____________
02600 -3 ^PRED ^ SUC ^ .CLASS = -3
02700 -2 ^CLASS^SIZE ^ .SIZE = 4
02800 ------------- .PROCPTR IS A REFERENCE TO THE PROCESS SLATED.
02900 -1 ^ PROCPTR ^ .TIMEFLD IS THE TIME WHEN THE PROCESS SHOULD
03000 0 ^ TIMEFLD ^ BECOME ACTIVE. IT HOLDS A FLOATING POINT VALUE.
03100 -------------
03200
03300
03400 TO SCHEDULE A PROCESS MEANS TO INSERT AN EVENTNOTICE REFERENCING IT
03500 IN THE SQS, THUS SPECIFYING THAT AN EVENT OF THIS PROCESS IS TO OCCUR
03600 AT A TIME NOT LESS THAN THE CURRENT TIME. THERE IS AT MOST ONE
03700 EVENTNOTICE REFERENCING A PROCESS AT ANY ONE TIME. A PROCESS IS SAID
03800 TO BE SLATED IF THERE IS AN EVENTNOTICE REFERENCING IT IN THE SQS,
03900 I.E. IT HAS PREVIOUSLY BEEN SCHEDULED BUT THE EVENT HAS NOT YET ENDED
04000 OR BEEN CANCELED. (ACTIVE OR SUSPENDED IN SIMULA.) IF THE PROCESS TO
04100 BE SCHEDULED IS ALREADY SLATED, AN ACTIVATE WILL BE IGNORED WHEREAS A
04200 REACTIVATE WILL CANCEL THE OLD EVENT AND RESCHEDULE THE PROCESS. THE
04300 PROCESS MAY BE SCHEDULED FIRST OR LAST AMONG THE PROCESSES ALREADY
04400 SLATED FOR THE GIVEN TIME, OR IT MAY BE SCHEDULED IMMEDIATELY BEFORE
04500 OR AFTER ANOTHER GIVEN SLATED PROCESS, AT THE SAME TIME AS THE GIVEN
04600 PROCESS. THE EVENTNOTICES IN SQS ARE ORDERED BY INCREASING .TIMEFLD.
04700
04800 A PROCESS IS IN ONE OF FOUR STATES:
04900 ACTIVE: CURRENTLY EXECUTING (HAS EVENTNOTICE BUT NOT REACTIVATION
05000 POINT.)
05100 SUSPENDED: NOT EXECUTING BUT HAS REACTIVATION POINT AND EVENTNOTICE.
05200 PASSIVE: HAS REACTIVATION POINT, NOT SLATED.
05300 TERMINATED: NO REACTIVATION POINT, NOT SLATED.
05400
05500 SINCE BLISS HAS NO GOTO, A TERMINATED PROCESS CAN NOT BE REVIVED BY
05600 NORMAL MEANS BUT ITS DATA MAY STILL BE USED.
05700
05800
05900 THE SEQUENCER
06000
06100 THE SEQUENCER IS A COROUTINE INSTANCE OF THE ROUTINE SEQUER WHICH IS
06200 EXCHJ'D INTO EACH TIME THE IDENTY OF THE FIRST ELEMENT OF THE SQS
06300 CHANGES, I.E. WHEN THE ACTIVE PROCESS SHOULD BECOME SUSPENDED,
06400 PASSIVE, OR TERMINATED. THE SEQUENCER SELECTS THE NEXT PROCESS TO
06500 BECOME ACTIVE FROM THE SQS, AND EXCHJ'S INTO IT. IT WILL ALSO SELECT
06600 EXECUTION-MODE ACCORDING TO INPUT, AND CALL THE RELEVANT ROUTINES.
06700 SEE SECTION ON DEBUGGING. THE SEQUENCER IS NOT A PROCESS IN THE
06800 POOMAS SENSE.
06900
07000
07100 THE VARIABLES:
07200
07300 .CURRENT IS A PROCESS DESCRIPTOR FOR THE ACTIVE PROCESS.
07400 .MAINPROG IS A PROCESS DESCRIPTOR FOR THE PROCESS THAT CALLED INITQPEP.
07500 .TIME IS THE CONTENTS OF THE TIME FIELD OF THE EVENTNOTICE FOR .CURRENT.
07600 .TALLY IS THE TOTAL NO. OF EVENTS EXECUTED.
07700 .STOPCOUNT IS THE LIMIT FOR .TALLY IN TALLY-MODE.
07800 .DEBUGGING CONTROLS THE EXECUTION MODE AS DECRIBED IN SECT. 13.
07900 VALUES ARE: 0: RUN, 1: LIMP, 2: WALK, 3: TALLY, 4: LIMP-CALL.
08000
08100
08200
08300 IN ADDITION TO THE MACROS LISTED UNDER BLIPP, THE FOLLOWING ANALOGOUS
08400 ONES FROM QPEP ARE OF INTEREST. NOTE THAT THE ACTUAL MUST BE A
08500 VARIABLE MAPPED TO OBJECT, OR AN EXPRESSION ENCLOSED IN PARENTHESIS,
08600 AS EXPLAINED ON P. 7-3. THEY EXPAND TO POINTERS TO THE FIELD IN
08700 QUESTION.
08800
08900 MACRO ! FIELDS IN OBJECTS.
09000 REACTPT(E) = (E[0])$, ! REACTIVATION POINT OF PROCESS.
09100 RARA(P) = (P[-1]<18,18>)$, ! RALF RAFL SAVE-FIELD.
09200 EVNOT(P) = (P[-1]<0,18>)$, ! EVENTNOTICE POINTER IN PROCESS.
09300 PROCPTR(E) = (E[-1])$, ! PROCESS POINTER IN EVNOT.
09400 TIMEFLD(E) = (E[0])$; ! TIME FIELD IN EVNOT.
09500
09600
09700
09800 FOLLOWING IS A DESCRIPTION OF THE ROUTINES OF QPEP.
09900
10000
10100 NOTE: THOSE ROUTINES THAT EXPECT PROCESS PARAMETERS, I.E. SCHEDULE,
10200 TERMINATE, CANCEL, KILL WILL "SEE THROUGH" REPRESENTATIVES AND
10300 OPERATE ON THE PROCESS IN QUESTION.
10400
10500
10600 INITIALISATION OF QPEP:
10700
10800 INITQPEP()
10900 WILL INITIALIZE SQS WITH ONE EVENTNOTICE REFERENCING THE CALLING
11000 PROGRAM, THE QPEP VARIABLES, AND THE SEQUENCER PROCESS. IF MEMORY IS
11100 REINITIALIZED BY INITMEM(), A CALL ON INITQPEP SHOULD FOLLOW.
11200 VALUE: 0.
11300
11400
11500
11600 SCHEDULING.
11700
11800 SCHEDULE(CODE,P,T)
11900 HANDLES ALL SCHEDULING. .P IS ADDRESS OF PROCESS TO BE SCHEDULED, .T
12000 IS THE TIME OR ADDRESS OF PROCESS, WHICH DETERMINES THE POSITION IN
12100 SQS. .CODE DETERMINES WHICH OF THE POSSIBLE CASES WE HAVE AS FOLLOWS:
12200
12300 ! BIT 33 ! BIT 34 ! BIT 35 !
12400 ---------------------------------------------------------
12500 0 ! REACTIVATE ! AT TIME .T ! FIRST OR BEFORE !
12600 1 ! ACTIVATE ! REL. TO PROC .T ! LAST OR AFTER !
12700 ---------------------------------------------------------
12800 VALUE: 0 IF ERRORS,
12900 -1 IF NOTHING WAS SCHEDULED (.P IS NONE).
13000 1 IF NO OTHER EVENT HAPPENED DURING SCHEDULE,
13100 2 IF OTHER EVENTS HAPPENED DURING SCHEDULE.
13200 (MAY OCCUR BY SCHEDULING FIRST AT PRESENT TIME).
13300
13400
13500
13600 FOR EASY DETERMINATION OF THE CODE PARAMETER USE MACRO CALLS AS
13700 FOLLOWS:
13800
13900 NOTE: BEFORE, AFTER, FIRSTAT, LASTAT ARE THEMSELVES MACROS
14000 OF NO PARAMETERS AND SMALL INTEGER CONSTANT VALUES.
14100
14200 ACTIVATE(P,BEFORE,T)
14300 ACTIVATES PROCESS AT .P BEFORE PROCESS AT .T.
14400
14500 ACTIVATE(P,AFTER,T)
14600 ACTIVATES PROCESS AT .P AFTER PROCESS AT .T.
14700
14800 ACTIVATE(P,FIRSTAT,T)
14900 ACTIVATES PROCESS AT .P FIRST AT TIME .T.
15000
15100 ACTIVATE(P,LASTAT,T)
15200 AS ABOVE BUT LAST AT TIME .T.
15300
15400 THE SAME OPTIONS ARE AVAILABLE FOR REACTIVATE,
15500 I.E. REACTIVATE(P,BEFORE,T) ETC.
15600
15700
15800 3 MORE MACROS AND ONE ROUTINE FACILITATE SCHEDULING:
15900
16000 HOLDSHORT(T)
16100 EQUIVALENT TO REACTIVATE(.CURRENT,FIRSTAT,.TIME+T)
16200
16300 HOLDLONG(T)
16400 EQUIVALENT TO REACTIVATE(.CURRENT,LASTAT,.TIME+T)
16500
16600 HOLD(T)
16700 EQUIVALENT TO HOLDLONG(T) OR REACTIVATE(.CURRENT,LASTAT,.TIME+T)
16800
16900 WAIT(S)
17000 INCLUDES .CURRENT IN LIST AT .S AND CANCELS IT (SEE BELOW).
17100
17200
17300 OTHER SEQUENCING ROUTINES:
17400
17500 TERMINATE(P)
17600 REMOVES ANY EVENTNOTICE FOR PROCESS AT .P FROM THE SQS AND CLEAR ITS
17700 REACTIVATIONPOINT. IT IS HEREAFTER TO BE REGARDED AS A DATA-
17800 STRUCTURE ONLY AND CAN NOT BE EXECUTED. IF .P IS .CURRENT, START NEXT
17900 PROCESS IN SQS.
18000 VALUE: 0 IF ERRORS, -1 IF .P IS NONE, OTHERWISE 1.
18100
18200 CANCEL(P)
18300 REMOVES ANY EVENTNOTICE FOR PROCESS AT .P FROM SQS, IF .P IS .CURRENT
18400 NEXT PROCESS IN SQS WILL BE STARTED.
18500 VALUE: 0 IF ERRORS, -1 IF .P IS NONE, OTHERWISE 1.
18600
18700 KILL(P)
18800 TERMINATES PROCESS AT .P AND RETURNS ITS SPACE TO FREELIST. IF .P IS
18900 A REP, THE REP-SPACE IS ALSO RELEASED. IF .P IS .CURRENT, NEXT
19000 PROCESS WILL BE STARTED.
19100 VALUE: 0 IF ERRORS, -1 IF .P IS NONE, OTHERWISE 1.
19200
19300
19400 TESTING FOR PROCESSHOOD:
19500
19600 ISPROCESS(P)
19700 CAN BE USED TO TEST IF AN OBJECT IS A PROCESS, I.E. IF ITS CLASS
19800 FIELD CONTAINS THE ADDRESS (ENTRYPOINT) OF A PROCEDURE. THIS IS DONE
19900 USING THE ISROFUN ROUTINE OF BLIPP AND SUFFERS FROM THE DEFICIENCIES
20000 OF THAT ROUTINE. I. E. NO-PARAMETER, NO-LOCALS, NO-REGISTERS SAVED
20100 ROUTINES CAN NOT BE DISTINGUISHED FROM SOME DATA AREAS.
20200 VALUE: 0 OR 1, 3 IF IN DOUBT.
00100 P O O M A S - F I L E
00200
00300
00400
00500 THE FILE POOMAS.BLI CONTAINS THOSE DECLARATIONS (GLOBAL, EXTERNAL,
00600 MACRO) THAT SHOULD PRECEDE THE USERS PROGRAM. THIS INCLUDES THE
00700 MACROS FROM CAP, AND AN 'EXTERNAL' DECLARATION AND CALL OF INITIO.
00800 SEE SECTION ON I/O IN BLIPP. THE USER SHOULD WRITE HIS PROGRAM AS A
00900 BLOCK WITH AN UNMATCHED 'END ELUDOM' AT THE END, AND COMPILE IT USING
01000 POOMAS.BLI AS A PREFIX.
01100
01200
01300 FOLLOWING ARE THE LAST LINES OF THE POOMAS.BLI FILE. THE USER MAY
01400 SPECIFY THE MAXIMAL SIZE OF HIS FREELIST AND THE NO. OF ERROR
01500 MESSAGES HE WANTS TO SEE BEFORE EXECUTION ABORTS BY ALTERING
01600 APPROPRIATE LINES MARKED BY ASTERISKS. TO ALTER THE SIZE OF THE
01700 MAIN-PROGRAM OBJECT IT IS SUFFICIENT TO CHANGE THE STACK-PARAMETER IN
01800 THE MODULE HEAD.
01900
02000
02100
02200 ! SET UP STACK FOR MAIN PROGRAM TO BE AN OBJECT.
02300
02400 SREG _ .SREG + #3000003;
02500 FREG _ .FREG + 3;
02600 (.FREG+1)<0,36> _ .FREG;
02700 BREG _ .BREG + 3;
02800
02900 ! INITIALIZE FIELDS OF MAIN PROGRAM AS FOR ANY OLD OBJECT.
03000
03100 MYSTACK _ NONE;
03200 (MYSTACK+1) _ (INITQPEP<0,0>+1)^18 ! ANY ROUTINE NAME OK AS CLASS.
03300 ! ADDING 1 TO GET CORRECT SUBTRACTION OF .SREG<LEFTHALF>.
03400 + .SREG<RIGHTHALF>-MYSTACK<0,0>-.SREG<LEFTHALF>;
03500 ! THIS WAS THE SIZE = USED + UNUSED PART OF STACK.
03600
03700 ! INITIALIZE I/O, BLIPP AND QPEP.
03800
03900 MAXMEM _ 15360; ! * * * MAXIMAL FREELISTSIZE * * * * *
04000
04100 INITIO();
04200 INITBLIPP();
04300 INITQPEP();
04400 ERRCOUNT _ 10; ! **** NO. OF ERROR MESSAGES PERMITTED. ***
04500
00100 R A N D O M N U M B E R G E N E R A T I O N
00200
00300
00400
00500 RANDOM NUMBER STREAMS:
00600
00700 A RANDOM NUMBER STREAM IN POOMAS IS A VARIABLE CONTAINING SUCCESSIVE
00800 VALUES OF A SEQUENCE OF INTEGERS. EACH MEMBER OF THE SEQUENCE IS
00900 OBTAINED FROM THE PREVIOUS BY ONE BASIC DRAWING ACCORDING TO THE
01000 LINEAR CONGRUENTIAL METHOD:
01100
01200 U _ (5^15 * .U + 7261067085) MOD 2^35
01300
01400 WHERE ^ STANDS FOR EXPONENTIATION RATHER THAN SHIFT.
01500
01600 FOR FURTHER INFORMATION THE READER IS REFERRED TO:
01700 KNUTH, D. E.,
01800 SEMINUMERICAL ALGORITHMS,
01900 ADDISON WESLEY 1969.
02000
02100 BY THEOREM A, P. 15 OF KNUTH, THE SEQUENCE OBTAINED IN THIS WAY HAS A
02200 PERIOD OF 2^35. FURTHERMORE, BY THE SPECTRAL TEST THE MULTIPLIER
02300 5^15 AND THE MODULUS 2^35 HAVE VERY DESIRABLE STATISTICAL PROPERTIES.
02400 SEE KNUTH, P. 88. THE ADDEND IS CHOSEN BY CRITERION (41), KNUTH P.
02500 78.
02600
02700 A RANDOM FLOATING POINT NUMBER IN [0.0,1.0> IS OBTAINED FROM THE
02800 ABOVE BY SHIFTING IT 8 BITS RIGHT AND FORCING THE SIGN AND EXPONENT
02900 TO OCTAL 200. THESE NUMBERS ARE USED BY ALL ROUTINES BELOW. THEY ARE
03000 UNNORMALIZED, BUT THE RESULTS OF ALL THE ROUTINES BELOW ARE EITHER
03100 INTEGER OR NORMALIZED FLOATING.
03200
03300 EACH OF THE ROUTINES FOR DRAWING FROM DISTRIBUTIONS HAS A RANDOM
03400 NUMBER STREAM AS ONE OF ITS PARAMETERS. THE USER SHOULD INITIALIZE
03500 THE STREAM BY ASSIGNING SOME INTEGER VALUE TO IT. EACH ROUTINE WILL
03600 ADVANCE ITS PARAMETER-STREAM BY PERFORMING ONE OR MORE DRAWINGS FROM
03700 IT, ACCORDING TO THE NEEDS OF THAT ROUTINE. HENCE THE STREAM
03800 PARAMETER HAS TO BE PASSED BY POINTER, - THE ADDRESS WILL SUFFICE.
03900 I. E. IF SEED4 CONTAINS THE STREAM, THE MOST EFFICIENT IS TO GIVE
04000 SEED4<0,0> (WITHOUT DOT) AS THE ACTUAL PARAMETER.
04100
04200
04300
04400 THE FOLLOWING ROUTINES ARE IMPLEMENTED:
04500
04600 RANDINT(A,B,U)
04700 A = INTEGER, LOWER BOUND.
04800 B = INTEGER, UPPER BOUND.
04900 U = RANDOM NUMBER STREAM.
05000 VALUE IS ONE OF THE INTEGERS .A, .A+1, . . . ,.B WITH EQUAL
05100 PROBABILITY.
05200 NOTE: .A < .B ASSUMED.
05300
05400 UNIFORM(A,B,U)
05500 A = REAL, LOWER BOUND.
05600 B = REAL, UPPER BOUND.
05700 U = RANDOM NUMBER STREAM.
05800 VALUES ARE REAL, UNIFORMLY DISTRIBUTED IN [.A,.B>.
05900 NOTE: .A < .B ASSUMED.
06000
06100 NORMAL(A,B,U)
06200 A = REAL, MEAN.
06300 B = REAL, STANDARD DEVIATION.
06400 U = RANDOM NUMBER STREAM.
06500 VALUES ARE REAL, NORMALLY DISTRIBUTED WITH THE ABOVE PARAMETERS. THE
06600 NORMAL DISTRIBUTION IS OBTAINED AS DESCRIBED IN:
06700 ABRAMOWITZ, M & STEGUN, I. A. (EDS)
06800 HANDBOOK OF MATHEMATICAL FUNCTIONS
06900 NTL. BUREAU OF STANDARDS APPLIED MATHS. SERIES NO. 55
07000 PP. 952 AND 933.
07100
07200 FASTNORMAL(A,B,U)
07300 A = REAL, MEAN.
07400 B = REAL, STANDARD DEVIATION.
07500 U = RANDOM NUMBER STREAM.
07600 VALUES ARE REAL, NORMALLY DISTRIBUTED WITH ABOVE PARAMETERS. NOTE:
07700 FASTNORMAL USES THE SUM OF 4 DRAWINGS FROM UNIFORM, RATHER THAN THE
07800 FORMULA USED BY NORMAL, TO OBTAIN THE DISTRIBUTION. IT IS ABOUT HALF
07900 AS SLOW AS NORMAL BUT LESS ACCURATE. THE EXACT ALGORITHM IS:
08000 .A + .B * ((.U1 + .U2 + .U3 + .U4) - 2.0) * SQRT(3.0)
08100 WHERE THE UI ARE UNIFORM IN [0,1>.
08200
08300 NEGEXP(A,U)
08400 A = REAL, INVERSE OF MEAN.
08500 U = RANDOM NUMBER STREAM.
08600 VALUES ARE REAL, DISTRIBUTED AS THE NEGATIVE EXPONENTIAL WITH MEAN
08700 1/.A. THIS IS THE SAME AS THE DISTRIBUTION OF "WAITING TIMES" IN A
08800 POISSON PROCESS WITH EXPECTED NO. OF ARRIVALS EQUAL TO .A PR. TIME
08900 UNIT. VALUE OBTAINED AS -LN(.U)/.A WHERE .U IS UNIFORM IN [0,1>.
09000
09100 POISSON(A,U)
09200 A = REAL, DISTRIBUTION PARAMETER.
09300 U = RANDOM NUMBER STREAM.
09400 VALUES ARE INTEGER, DISTRIBUTED AS THE POISSON DISTRIBUTION. THE
09500 VALUE, N, IS OBTAINED BY .N DRAWINGS, UNIFORM IN [0,1>, WHERE .N IS
09600 THE SMALLEST INTEGER S.T.
09700 1.0 * U1 * U2 * . . . * UN < EXP(-.A)
09800 IF .A > 20.0, NORMAL(.A,SQRT(.A),.U) IS USED IF .A < 0.0, 0 IS USED.
09900
10000 ERLANG(A,B,U)
10100 A = REAL, INVERSE MEAN.
10200 B = REAL, DESCRIBED BELOW.
10300 U = RANDOM NUMBER STREAM.
10400 VALUES ARE REAL, DISTRIBUTED AS THE ERLANG DISTRIBUTION WITH MEAN
10500 1/.A AND STANDARD DEVIATION 1/(.A*SQRT(.B)). IF .B IS INTEGER IT IS
10600 OBTAINED BY .B BASIC DRAWINGS (UNIFORM IN [0,1>) AS:
10700 -(LN(.U1) + . . . + LN(.UB)) / (.A * .B)
10800 IF .B IS NOT INTEGER THE ABOVE TERM IS FORMED USING FIX .B DRAWINGS,
10900 AND THE FOLLOWING TERM ADDED:
11000 - (.B - FIX .B) * LN(.U) / (.A * .B)
11100 I. E. ANOTHER DRAWING IS REQUIRED.
11200 NOTE: WE MUST HAVE .A > 0, .B > 0 AND THE B SUPPLIED SHOULD ALWAYS
11300 BE A FLOATING POINT NUMBER EVEN IF ITS VALUE IS INTEGER.
11400
11500 DISCRETE(A,N,U)
11600 A = REAL VECTOR, CUMULATIVE DISTRIBUTION (ALMOST).
11700 N = INTEGER, LENGTH OF A (A INDEXED FROM 0 THROUGH .N).
11800 U = RANDOM NUMBER STREAM.
11900 A IS PASSED BY ADDRESS OF FIRST ELEMENT. VALUEIS INTEGER IN [0,.N+1]
12000 DEFINED BY BEING THE LEAST INTEGER I SUCH THAT .A[.I] > .U, U BEING
12100 OBTAINED BY A DRAWING UNIFORM IN [0,1>. IF THE INEQUALITY IS NOT
12200 SATISFIED FOR ANY VALUE IN [0,.N], .N+1 IS RETURNED.
12300
12400 LINEAR(A,B,N,U)
12500 A = REAL VECTOR, ORDINATES OF CUMULATIVE DISTRIBUTION.
12600 B = REAL VECTOR, ABSCISSAE OF CUMULATIVE DISTRIBUTION.
12700 N = INTEGER, LENGTH OF A AND B (INDEXED FROM 0 THROUGH .N).
12800 U = RANDOM NUMBER STREAM.
12900 A AND B ARE PASSED BY ADDRESSES OF FIRST ELEMENTS. A AND B CONSTITUTE
13000 A NON-EQUIDISTANT TABLE FOR A CUMULATIVE DISTRIBUTION FUNCTION F, I.
13100 E. .A[.I] = F(.B[.I]) FOR .I = 0,1,2, ... .N. .A[0] SHOULD BE 0.0,
13200 .A[.N] SHOULD BE 1.0. .A[.I+1] GEQ .A[.I] AND .B[.I+1] > .B[.I]
13300 ASSUMED FOR .I IN [0,.N-1]. VALUES ARE REAL, OBTAINED BY ONE BASIC
13400 DRAWING UNIFORM IN [0,1> AND INVERSE LINEAR INTERPOLATION IN THE
13500 TABLE.
00100 C O L L E C T I O N O F S T A T I S T I C S :
00200
00300
00400
00500 ACCUM(SUM,OLDT,VAL)
00600 SUM - ADDRESS OF VARIABLE WHERE SUM IS ACCUMULATED.
00700 OLDT - ADDRESS OF VARIABLE WHERE PREVIOUS TIME THIS SUM WAS UPDATED
00800 IS STORED.
00900 VAL - REAL, VALUE OF FUNCTION OVER LAST TIME-INTERVAL.
01000 WILL ADD (.TIME - @.OLDT)*.VAL TO THE VARIABLE AT .SUM, I.E. THE TIME
01100 INTEGRAL OF THE FUNCTION WHOSE VALUE IS .VAL OVER THE LAST TIME
01200 INTERVAL, IS COMPUTED. OLDT MUST BE INITIALIZED BY THE USER BUT IS
01300 UPDATED BY ACCUM. .VAR MUST BE INITIALIZED TO 0 BY THE USER.
01400
01500 HISTO(ARR,VAL)
01600 ARR - ADDRESS OF A VECTOR WHERE HISTOGRAM IS ACCUMULATED.
01700 VAL - REAL, VALUE TO BE ADDED TO HISTOGRAM.
01800 THE VECTOR MUST HAVE THE FORMAT SHOWN.
01900
02000 ------------ N - INTEGER, NO. OF COLOUMNS IN THE HISTOGRAM
02100 ! N ! LESS 1.
02200 !------------! WIDTH - REAL, WIDTH OF EACH COLOUMN IN HISTO-
02300 ! WIDTH ! GRAM IN UNITS OF THE OBSERVED VALUE.
02400 !------------! LOW - REAL, LOWER BOUND FOR .VAL (ACTUAL .VAL'S
02500 ! LOW ! THAT ARE SMALLER COUNT AS .LOW).
02600 !------------! SUM VAL - REAL, SUM OF VALUES IN HISTOGRAM.
02700 ! SUM VAL ! SUM VAL^2 - REAL, SUM OF SQUARES OF VALUES.
02800 !------------!
02900 ! SUM VAL^2 ! N, WIDTH AND LOW MUST BE PRESET BY THE USER,
03000 !------------! AND THE REST OF THE VECTOR CLEARED TO ZEROES.
03100 ! COL. 0 ! THIS IS DONE BY THE ROUTINE INITHISTO DESCRIBED
03200 ! COL. 1 ! BELOW. THE VECTOR MUST HAVE .N+6 OR MORE ELE-
03300 ! ! MENTS IN ALL. COLOUMN RANGES WILL BE:
03400 ! ! [.LOW, .LOW+.WIDTH>
03500 ! ! [.LOW+.WIDTH, .LOW+2*.WIDTH>
03600 ! ! . . .
03700 ! COL. N ! [.LOW+.N*.WIDTH, INFINITY>
03800 ------------
03900
04000 INITHISTO(ARR,N,WIDTH,LOW)
04100 ARR - ADDRESS OF ARRAY AS DESCRIBED ABOVE UNDER HISTO.
04200 N - INTEGER, VALUE TO BE PUT IN THE N FIELD.
04300 WIDTH - REAL, VALUE FOR THE WIDTH FIELD.
04400 LOW - REAL, VALUE FOR THE LOW FIELD.
04500 THE VECTOR IS INITIALIZED AS REQUIRED BY THE HISTO ROUTINE.
04600
04700 HPRINT(CHNL,ARR)
04800 CHNL - INTEGER, CHANNEL NUMBER AS IN BLISS I/O FOR PRINTING.
04900 ARR - ADDRESS OF HISTOGRAM-VECTOR AS DESCRIBED UNDER HISTO.
05000 THE HISTOGRAM WILL BE PRINTED ON THE CHANNEL INDICATED, ONE LINE PR
05100 COLOUMN. EACH LINE HAS THE FOLLOWING FORMAT:
05200 OBSVAL !**. . .* NOBS(PERCENT)CUMPERCENT
05300 WHERE
05400 OBSVAL - LOWER BOUND FOR THE HISTOGRAM COLOUMN, THE COLOUMN SPANNING
05500 THE RANGE [.OBSVAL, .OBSVAL+.WIDTH>
05600 **. . .* - SCALED SO THAT THE LONGEST COLOUMN REQUIRES 100 ASTERISKS.
05700 NOBS - NO. OF OBSERVATIONS IN COLOUMN.
05800 PERCENT - PERCENTAGE OF OBSERVATIONS IN COLOUMN.
05900 CUMPERCENT - CUMULATIVE PERCENTAGE.
06000
06100 THE PRINTING OF COLOUMNS WIL STOP WHEN .CUMPERCENT EXEEDS 99.98.
06200 FOLLOWING THE HISTOGRAM IS A LINE GIVING THE MEAN, STANDARD DEVIATION
06300 AND SCALE USED (OBSERVATIONS PR. '*').
00100 D E B U G G I N G A I D S :
00200
00300
00400
00500 THE POOMAS SEQUENCER CAN RUN IN 4 DIFFERENT MODES:
00600
00700 RUN THE PROGRAM WILL RUN AT MAXIMAL SPEED WITH NO TYPEOUT.
00800
00900 TALLY AS RUN, BUT TRANSFERS TO LIMP MODE AFTER A SPECIFIED NO.
01000 OF EVENTS.
01100
01200 WALK BEFORE EACH EVENT THE SEQUENCER WILL TYPE THE CLASS, STACK
01300 BASE AND EVENT-TIME OF THE PROCESS ABOUT TO BECOME ACTIVE.
01400
01500 LIMP TYPE-OUT AS FOR WALK MODE FOLLOWED BY COLON. THE SEQUENCER
01600 NOW WAITS FOR INPUT.
01700
01800 IF "<RETURN>" IS GIVEN THE PROCESS WILL EXECUTE THE EVENT.
01900
02000 IF "B <RETURN>" IS TYPED, THE PROCESS WILL CALL THE DUMMY
02100 ROUTINE TRACEBREAK AS THE FIRST THING IN THE EVENT. THE USER
02200 MAY SET A BREAKPOINT HERE FOR FURTHER DEBUGGING IN DDT.
02300 NOTE: THIS BREAKPOINT IS NOT OBEYED THE FIRST TIME CONTROL
02400 ENTERS A PROCESS UNLESS THE USER HAS INCLUDED A CALL ON
02500 TRACEBREAK AS THE FIRST STATEMENT. IF THIS CALL IS OF FORM
02600 "IF .VREG THEN TRACEBREAK()" IT WILL BE CONDITIONALLY OBEYED
02700 AS DESCRIBED ABOVE. IF IT IS A PLAIN CALL, THE BREAKPOINT
02800 WILL ALWAYS BE OBEYED REGARDLESS OF EXECUTION MODE.
02900
03000 IF "T <OCTAL CONSTANT> <RETURN>" IS TYPED, THE SEQUENCER WILL
03100 GO INTO TALLY-MODE AND RETURN TO LIMP MODE AFTER THE
03200 INDICATED NO. OF EVENTS. NO CONSTANT MEANS 1.
03300
03400 IF "C <PROCEDURE>(<PARAM>, . . . ,<PARAM>) <RETURN>" IS TYPED
03500 THE PROCEDURE CALL WILL BE EXECUTED AND ITS VALUE TYPED IN
03600 OCTAL. UP TO 8 PARAMETERS ARE ACCEPTED. THE PARAMETERS AS
03700 WELL AS THE PROCEDURE NAME MAY CONSIST OF NAMES KNOWN BY DDT
03800 AND OCTAL CONSTANTS COMBINED BY "+" AND "-". NO DOTS SHOULD
03900 BE USED, AND THE VALUES OF THE EXPRESSIONS INDICATE THE
04000 ENTRYPOINT TO THE PROCEDURE OR THE ADDRESS WHERE THE VALUE OF
04100 THE PARAMETER IS TO BE FOUND RESPECTIVELY. SPACES ARE
04200 IGNORED OUTSIDE OF SYMBOLS AND CONSTANTS. HENCE:
04300 C CARDINAL( QUEUE + 2 ) <RETURN>
04400 IS A LEGAL INPUT. AFTER THE VALUE IS TYPED OUT, THE COLON
04500 WILL AGAIN APPEAR AND THE SYSTEM AWAITS FURTHER INPUT IN
04600 LIMP-MODE.
04700
04800 IF "R <RETURN>" OR "L <RETURN>" IS TYPED, THE SEQUENCER WILL
04900 GO INTO RUN OR WALK MODE RESPECTIVELY.
05000
05100 THE SYSTEM IS INITIALLY IN LIMP MODE.
05200
05300 THE USER MAY TYPE "L", "W", "R", "T" OR "T<OCTAL>" AT ANY TIME TO
05400 CHANGE MODES. HE MAY ALSO TYPE "B" IN RUN OR WALK MODES WHICH WILL
05500 TAKE THE SYSTEM INTO LIMP MODE AND OBEY THE BREAKPOINT. TYPING A
05600 "<RETURN>" HAS EFFECT ONLY IN LIMP MODE.
05700
05800 ALL TYPE-IN AT ANY TIME MUST BE FOLLOWED BY A "<RETURN>", AND ACTION
05900 IS DETERMINED ON THE BASIS OF THE FIRST CHARACTER OF THE LINE. IN THE
06000 NEW MONITOR (CMU6 - DEC LEVEL D) THE USER MAY HAVE TO FOLLOW HIS
06100 <RETURN> BY A <CONTROL> O (CONTROL OH). THIS IS DUE TO A BUG IN THE
06200 TTCALL UUO.
06300
06400 A SLIGHTLY MODIFIED AND EXTENDED VERSION OF THE STANDARD "HELP"-
06500 PACKAGE IS USED FOR THE ABOVE OUTPUT, AND ALL THE NORMAL FACILITIES
06600 OF HELP ARE AVAILABLE. THE POOMAS VERSION OF HELP IS CALLED PHELP.
06700
06800 PROGRAMS MAY BE LOADED WITHOUT DDT, THE 'MISSING GLOBAL' MESSAGE FOR
06900 DDTEND MAY BE IGNORED AND THE PROGRAM RUN IN RUN MODE WITHOUT
07000 BREAKPOINTS. THE DDT SYMBOLTABLE WILL IN SOME CASES BE AVAILABLE.
07100
07200 ROUTINES USEFUL DURING DEBUGGING THAT ARE DESCRIBED ELSEWHERE ARE:
07300 CARDINAL - SECT. 7
07400 TYPLIS - SECT 7.
07500
07600
07700
07800 BREAKPOINT DEBUGGING.
07900
08000 THE NORMAL FACILITIES OF DDT AND HELP ARE AVAILABLE. (HELP IS PART
08100 OF POOLIB, THE POOMAS LIBRARY).
08200
08300 BPCALL()
08400 THE LIMP - MODE CALL FEATURE DESCRIBED ABOVE IS AVAILABLE THROUGH THE
08500 ROUTINE BPCALL AND THE XALTX ROUTINE OF HELP. THE ADVANTAGE OF THIS
08600 OVER USING THE $X FEATURE DIRECTLY IS THAT PARAMETERS ARE MORE EASILY
08700 TRANSMITTED AND THAT REGISTERS ARE PROPERLY PRESERVED. BPCALL WILL
08800 CONTINUOUSLY TYPE " :" AND EXPECT INPUT OF FORM:
08900 "C <ROUTINE>(<PARAM>,...,<PARAM>)"
09000 AS DESCRIBED ABOVE. IT WILL RETURN TO DDT WHEN THE LEADING "C" IS
09100 NOT PRESENT. TO USE THIS FROM A BREAKPOINT DO:
09200 1) SET XALTX0 TO BPCALL: XALTX0/ XXXX BPCALL
09300 2) CALL XALTX: PUSHJ 0,XALTX$X
00100 E R R O R H A N D L I N G & M E S S A G E S:
00200
00300
00400
00500 WHEN POOMAS DETECTS AN ERROR, MOST OFTEN IN AN ACTUAL PARAMETER, IT
00600 WILL CALL BLIPPERROR. IT WILL TYPE THE ERROR NUMBER AND ERROR COUNT,
00700 THE LATTER AFTER IT HAS BEEN DECREASED BY ONE. WHEN THE ERROR COUNT
00800 REACHES 0, THE EXECUTION WILL HALT. IF A BREAKPOINT WAS SET AT
00900 DDTBREAK, THIS WILL BE OBEYED.
01000
01100 THE MEANINGS OF THE ERROR NUMBERS ARE:
01200
01300 ERROR MEANING
01400
01500 1 REQUEST FOR LESS THAN 2 WORDS TO GETSPACE.
01600 2 NO SPACE ON FREE-LIST
01700 3 TRYING TO RELEASE ALREADY FREE OBJECT, OR NONE.
01800 4 TRYING TO REMOVE HEAD OR NONE.
01900 5 MEANINGLESS ARGUMENT TO INSERTAFTER.
02000 6 NOT ENOUGH SPACE FOR HEAD.
02100 7 NOT ENOUGH SPACE FOR OBJECT.
02200 10 NOT ENOUGH SPACE FOR REPRESENTATIVE.
02300 11 MEANINGLESS PARAMETER TO INSERTBEFORE.
02400 12 ACTUAL WAS NOT A LIST.
02500 13 MEANINGLESS PARAMETER FOR INCLUDE.
02600 14 MEANINGLESS PARAMETER FOR REPLACE.
02700 15 STACK OVERFLOW IN PROCESS.
02800 16 MEANINGLESS PARAMETER FOR MAPLIST.
02900 17 NO MORE CORE FROM MONITOR.
03000
03100 20 ZERO ARG. TO LOGARITHM (NEGEXP, NORMAL, ERLANG).
03200 21 TOO LARGE ARG. TO EXPONENTIAL (POISSON).
03300 22 NEGATIVE ARG FOR SQRT (NORMAL, POISSON).
03400 23 ILLEGAL ARGUMENT FOR ERLANG.
03500 24 A[.N] IS NOT 1.0 IN PARAMETERS TO LINEAR.
03600
03700 30 PARAMETER NOT PROCESS WHERE SUCH EXPECTED.
03800 31 SQS IS EMPTY.
03900 32 SCHEDULING IN THE PAST.
04000 33 SCHEDULING RELATIVE TO IDLE PROCESS.
04100 37 ILLEGAL REMOTE ACCESS.
04200
04300
04400 ERROR MESSAGES FROM CALLS IN LIMP-MODE:
04500
04600 SYMB! ATOM DOESN'T START WITH LETTER OR DIGIT.
04700 PROC! PROCEDURE NAME NOT FOUND IN DDT-SYMBOLTABLE.
04800 PAR! PARAMETER " " " " " " " " " " "
04900 MANY! TOO MANY PARAMETERS (> 8).
05000 LPAR! NO LEFT PARENTHESIS IN CALL.
05100 RPAR! NO RIGHT PARENTHESIS IN CALL.
00100 A S M A L L P O O M A S E X A M P L E
00200
00300
00400
00500 SUPERMARKET CHECK-OUT QUEUES.
00600
00700
00800 BEGIN
00900
01000 %<THE PROGRAM SIMULATES THE CHECKOUT - SECTION OF A SUPERMARKET.
01100 CUSTOMERS ARRIVE AT THE FRONT OF THE MARKET AND WAIT
01200 IN THE SHORTEST QUEUE, UNTIL THEY CAN BE SERVED.
01300 STATISTICS ARE GATHERED ON HOW LONG CUSTOMERS HAVE TO WAIT IN
01400 LINES.
01500 >%
01600
01700 ! N IS NO. OF CLERKS, Q ARE THE QUEUES, WTIME THE WAITING TIME
01800 ! HISTOGRAM, CLERK CONTAINS PROCESS DESCRIPTORS FOR CLERKS.
01900 ! U,V ARE RANDOM NUMBER STREAMS, COUNT IS CUSTOMERCOUNT.
02000 ! GLOBALS ARE ACCESSIBLE BY NAME FROM DDT, THAT'S WHY.
02100
02200 MACRO N = 3$;
02300 GLOBAL Q[N], WTIME[21], CLERK[N];
02400 EXTERNAL NEGEXP,NORMAL; ! RANDOM NUMBER GENERATORS USED.
02500 OWN U,V,COUNT;
02600
02700
02800 GLOBAL ROUTINE INITIO =
02900 ! ROUTINE TO INITIALIZE I/O TO CHANNELS DIFFERENT FROM 0.
03000 ();
03100
03200 ROUTINE CUSTOMER(TELL)=
03300 ! THIS IS THE CLASS CUSTOMER.
03400 BEGIN
03500 LOCAL T;
03600 OWN K,J,LEN;
03700
03800 IF .VREG THEN TRACEBREAK();
03900
04000 ! NOW CREATE NEXT CUSTOMER AND SCHEDULE HIS ARRIVAL.
04100 ACTIVATE( NEW(CUSTOMER(TELL+1),100),
04200 LASTAT,
04300 .TIME FADR NEGEXP(0.50,V<0,0>)
04400 );
04500
04600 ! REMEMBER ARRIVAL TIME IN LOCAL.
04700 T_.TIME;
04800
04900 ! FIND SHORTEST QUEUE
05000 K_0;
05100 LEN_CARDINAL(.Q[.K]);
05200 INCR II FROM 1 TO N-1 DO
05300 IF CARDINAL(.Q[.II]) LSS .LEN THEN
05400 BEGIN K_.II; LEN_ CARDINAL(.Q[.K]) END;
05500
05600 ! NOW ENTER THE SHORTEST QUEUE, BUT FIRST ACTIVATE ITS CHECK-
05700 ! OUT CLERK IN CASE HE WAS IDLE.
05800 ACTIVATE(.CLERK[.K],AFTER,.CURRENT);
05900 WAIT(.Q[.K]);
06000
06100 ! REACTIVATION POINT SET HERE. CUSTOMER IS ACTIVATED AGAIN BY
06200 ! CLERK WHEN HE HAS BEEN SERVED.
06300
06400 ! COMPUTE TIME SPENT IN QUEUE
06500 T_(.TIME FSBR .T); J_FIX .T;
06600
06700
06800 ! INCREMENT APPROPRIATE ENTRY IN WAITING-TIME HISTOGRAM.
06900 IF .J LSS 20 THEN WTIME[.J]_.WTIME[.J]+1
07000 ELSE WTIME[20]_.WTIME[20]+1;
07100
07200 ! IF ENOUGH CUSTOMERS SERVED TO GET GOOD STATISTICS, FINISH.
07300 COUNT_.COUNT+1;
07400 IF .COUNT GTR 1000 THEN
07500 ACTIVATE(.MAINPROG,AFTER,.CURRENT);
07600
07700 ! THIS CUSTOMER IS NOW FINISHED. RETURN HIM TO THE FREE LIST.
07800 KILL(.CURRENT)
07900 END; ! END OF CUSTOMER.
08000
08100
08200 ROUTINE SERVICE(I)=
08300 ! THIS ROUTINE DESCRIBES THE CLASS OF CLERKS.
08400 BEGIN
08500
08600 IF .VREG THEN TRACEBREAK();
08700
08800 WHILE 1 DO
08900 BEGIN
09000
09100 ! IS THERE A CUSTOMER IN THE QUEUE?
09200 WHILE NOT EMPTY(.Q[.I]) DO
09300 ( ! YES. SERVE HIM, THEN ACTIVATE HIM.
09400 HOLD(NORMAL(5.0,1.0,U<0,0>));
09500 ACTIVATE(FIRST(.Q[.I]),AFTER,.CURRENT);
09600 REMOVE(FIRST(.Q[.I]))
09700 );
09800 ! NO. REST UNTIL ONE ARRIVES. HE'LL ACTIVATE ME.
09900 CANCEL(.CURRENT)
10000 END; ! END OF CLERK LOOP
10100
10200 END; ! END OF SERVICE.
10300
10400
10500 ! INITIALIZE RANDOM NUMBER STREAMS, COUNTER, HISTOGRAM,
10600 ! QUEUES AND CLERKS.
10700
10800 U_11;
10900 V_7;
11000 COUNT_0;
11100 INCR II FROM 0 TO 20 DO WTIME[.II]_0;
11200 INCR II FROM 0 TO N-1 DO Q[.II]_MAKELIST();
11300 INCR II FROM 0 TO N-1 DO CLERK[.II]_NEW(SERVICE(.II),100);
11400
11500 ! INITIALIZE FIRST CUSTOMER, HE'LL TAKE CARE OF THE REST.
11600 ACTIVATE(NEW(CUSTOMER(10),100),AFTER,.CURRENT);
11700
11800 ! WAIT TILL STATISTICS IS GATHERED.
11900 CANCEL(.CURRENT);
12000
12100 ! OUTPUT STATISTICS.
12200 TYPE('HISTO',0); TYPE('GRAM ',0); TYPE('OF WA',0);
12300 TYPE('ITING',0); TYPE(' TIME',0); TYPE('S:',1);
12400 INCR II FROM 0 TO 20 DO
12500 (TYPDEC(.II,0);TYPE(' ',0);TYPDEC(.WTIME[.II],1));
12600 TERMIO();
12700
12800 END ! CORRESPONDS TO BEGIN IN THIS PROGRAM.
12900
13000 END ! CORRESPONDS TO BEGIN FIRST IN POOMAS.BLI
13100
13200 ELUDOM
13300
13400
13500
13600 NOW ASSUME THAT THE PROGRAM ABOVE IS ON FILE MARKET.BLI AND THAT
13700 POOMAS.BLI, POOIO.REL AND POOLIB.REL ARE ON THE USERS DISK AREA.
13800
13900 TO COMPILE THIS PROGRAM GIVE THE FOLLOWING COMMAND:
14000
14100 .R BLISS
14200 *DSK:MARKET,DSK:MARKET_DSK:POOMAS,MARKET
14300
14400 TO RUN (DEBUG) IT, TYPE THE COMMAND
14500
14600 .DEBUG POOLIB,POOIO,MARKET
14700
14800
14900
15000 A SAMPLE TERMINAL SESSION WITH THE ABOVE PROGRAM:
15100
15200
15300 COMMENTS ARE GIVEN TO THE RIGHT, PRECEEDED BY A !.
15400
15500 .R BLISS
15600 *DSK:MARKET,_DSK:POOMAS,MARKET ! STANDARD COMPILATION WITHOUT LISTING.
15700
15800
15900 MODULE LENGTH =364+2+27
16000 COMPILATION COMPLETE
16100
16200
16300
16400
16500 *^C
16600 .DEB POOLIB,POOIO,MARKET
16700 LOADING
16800
16900 LOADER 11K CORE
17000 EXECUTION
17100
17200 DDTBREAK$B TRACEBREAK$B ! SET POOMAS STANDARD BREAKPOINTS.
17300 $G
17400 CUSTOM AT 23234 T= 0.000 : ! STARTING IN LIMP MODE.
17500 SERVIC AT 23465 T= 0.000 : ! CONTINUE LIMPING WHILE RETURNS ARE TYPED.
17600 CUSTOM AT 23145 T= 1.694 :
17700 SERVIC AT 23402 T= 1.694 :W ! TRANSFER TO WALK MODE.
17800 SERVIC AT 23465 T= 3.416
17900 CUSTOM AT 23234 T= 3.416
18000 SERVIC AT 23402 T= 6.698
18100
18200 . . . ! WALKING FOR A WHILE.
18300
18400 SERVIC AT 23402 T= 12.088
18500 CUSTOM L ! L TYPED, REPLIED IN MIDLINE.
18600 AT 22767 T=12.088
18700 SERVIC AT 23465 T= 12.603 :C CARDINAL(Q) ! BACK IN LIMP MODE AS A RESULT.
18800 ! OF TYPING THE L. CHECK SIZES
18900 ! OF QUEUES AND SQS.
19000 #1 ! Q[0] HAS 1 MEMBER.
19100 :C CARDINAL(Q+1)
19200 #0 ! Q[1] HAS NONE
19300 :C CARDINAL(Q+2)
19400 #1 ! Q[2] HAS 1.
19500 :C CARDINAL(SQS)
19600 #3 ! SQS HAS 3 EVENTNOTICES.
19700 :B ! GET INTO DDT AT BREAKPOINT.
19800 $2B>>TRACEB
19900 TALLY/ 21 ! 21 EVENTS HAPPENED
20000 DEBUGGING/ 1 ! WE'RE IN LIMP MODE.
20100 $P
20200 CUSTOM AT 23056 T= 12.603 :R ! RUN IT FAST FOR SOME SECONDS.
20300 L ! BACK INTO LIMP MODE BY TYPING L.
20400 CUSTOM AT 20536 T=360.025 :B
20500 $2B>>TRACEB
20600 TALLY/ 1120 ! WERE MAKING PROGRESS. GO ON.
20700 $P
20800 CUSTOM AT 17771 T= 362.290 :T 2000 ! STOP AGAIN AFTER 2000 EVENTS.
20900 CUSTOM AT 20536 T= 974.193 :B ! DO A BREAKP. STOP AGAIN.
21000 CUSTOM AT 20453 T= 974.304 :B ! THESE CUSTOMERS ENTERED AT TOP
21100 SERVIC AT 23317 T= 975.134 :B ! WHERE TRACEBREAK IS'NT CALLED.
21200 $2B>>TRACEB
21300 TALLY/ 3124 STOPCOUNT/ 3120
21400 $P
21500 CUSTOM AT 21303 T=975.134 :R ! RUN TIL FINISHED.
21600 HISTOGRAM OF WAITING TIMES:
21700 0 0
21800 1 0
21900 2 0
22000 3 18
22100
22200 . . .
22300
22400 19 26
22500 20 157
22600
22700 EXIT
22800 ^C
22900
23000 AND THAT WAS THE END OF THE RUN
00100 C O M M O N P I T F A L L S :
00200
00300
00400
00500 STACK OVERFLOW
00600
00700 THE STACK FOR EACH PROCESS MUST BE ABLE TO ACCOMODATE ALL ROUTINES
00800 CALLED WITHIN THIS PROCESS. IF ERRORS OCCUR OR IF THE HELP ROUTINES
00900 ARE USED, THE DEPTH OF NESTING USUALLY GETS LARGE. THIS ALSO HAPPENS
01000 IN OTHER MORE NORMAL CIRCUMSTANCES. AN OBJECT SIZE OF 100 IS
01100 PROBABLY A REASONABLE CHOICE, AT LEAST DURING DEBUGGING. BLISS DOES
01200 NOT ALWAYS DETECT STACK OVERFLOW, IN PARTICULAR WHEN A CONSTANT IS
01300 ADDED TO THE STACKPOINTER TO ACCOMODATE LOCAL VARIABLES. THIS MAY
01400 HAVE DISASTROUS EFFECTS ON THE POOMAS DATASTRUCTURES. HENCE CHECKS
01500 ARE BUILT INTO THOSE POOMAS ROUTINES THAT OFTEN ARE DEEPLY NESTED,
01600 LIKE GETSPACE, RELEASESPACE.
01700
01800
01900 OBJECTS AND OBJECT REFERENCES.
02000
02100 SINCE THE LOCATION OF AN OBJECT IN MEMORY IN GENERAL IS UNKNOWN TO
02200 THE PROGRAMMER, IT IS USUALLY MANIPULATED THROUGH SOME VARIABLE
02300 HOLDING ITS ADDRESS (OR THE VALUE OF A CREATE EXPRESSION). THESE
02400 VARIABLES MAY, IN A SENSE, BE REGARDED AS NAMES OF THE OBJECTS.
02500 VARIABLES OF THIS KIND, I.E. WHICH ARE EXPECTED TO HOLD ADDRESSES OF
02600 OBJECTS, MAY BE MAPPED TO THE STRUCTURE OBJECT. OBJECTS THEMSELVES
02700 ARE USUALLY NOT AVAILABLE FOR MAPPING.
02800
02900
03000 CALL FORMATS FOR MACROS VS. ROUTINES.
03100
03200 THE MACROS THAT GIVE ACCESS TO THE FIELDS OF OBJECTS ORIGINALLY TOOK
03300 AS THEIR PARAMETER AN IDENTIFIER MAPPED TO OBJECT. THEY WILL NOW
03400 ALSO ACCEPT EXPRESSIONS THAT EVALUATE TO ADDRESSES OF OBJECTS. SUCH
03500 EXPRESSIONS MUST BE ENCLOSED IN PARENTHESES IN ORDER THAT THE
03600 STRUCTURE EVALUATION MAY BE CORRECTLY DONE. THE MACRO CALLS EXPAND
03700 TO POINTERS (IN THE NORMAL BLISS SENSE) TO THE FIELD IN QUESTION.
03800 HENCE TO GET THE ADDRESS OF THE SUCCESSOR TO SOME OBJECT WRITE
03900 ".SUC(OB)" OR ".SUC((.OB))", RATHER THAN "SUC(.OB)". ON THE OTHER
04000 HAND ROUTINES USUALLY WANT THE ADDRESS OF AN OBJECT AS THEIR ACTUAL.
04100 HENCE "REMOVE(.OB)" WOULD BE CORRECT, AS OPPOSED TO ".REMOVE(OB)".
04200 BLISS MACROS MAY NOT BE USED RECURSIVELY, HENCE ".SUC((.SUC(OB))" IS
04300 ILLEGAL BUT ".PRED((.SUC(OB))" IS LEGAL.
04400
04500
04600 REMOTE ACCESSING MACROS
04700
04800 THE PARAMETERS ARE AN ADDRESS AND A (SMALL) VALUE RESPECTIVELY. THE
04900 MACROS EXPAND TO ADDRESSES. THE EXAMPLES IN SECT. 8 SHOULD BE
05000 STUDIED CAREFULLY.
05100
05200
05300 MIXED MODE ARITHMETIC
05400
05500 THERE AIN'T NO SUCH THING AS AUTOMATIC TYPE CONVERSION, AND THE MODE
05600 OF ARITHMETIC IS DETERMINED BY THE OPERATOR WRITTEN. THUS: CHECK
05700 FOUR TIMES, THEN CHECK AGAIN.
05800
05900
06000
06100
06200 END OF POOMAS DOCUMENTATION.