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/CLOCK HANDLER FOR RTS-8 MODIFIED 1/3/74 / / / / / / / / / /COPYRIGHT (C) 1974 BY DIGITAL EQUIPMENT CORPORATION / / / / / / / / / / /THE INFORMATION IN THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE /AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY DIGITAL EQUIPMENT /CORPORATION. DIGITAL EQUIPMENT CORPORATION ASSUMES NO RESPONSIBILITY /FOR ANY ERRORS THAT MAY APPEAR IN THIS DOCUMENT. / /THE SOFTWARE DESCRIBED IN THIS DOCUMENT IS FURNISHED TO THE PURCHASER /UNDER A LICENSE FOR USE ON A SINGLE COMPUTER SYSTEM AND CAN BE COPIED /(WITH INCLUSION OF DIGITAL'S COPYRIGHT NOTICE) ONLY FOR USE IN SUCH /SYSTEM, EXCEPT AS MAY OTHERWISE BE PROVIDED IN WRITING BY DIGITAL. / /DIGITAL EQUIPMENT CORPORATION ASSUMES NO RESPONSIBILITY FOR THE USE /OR RELIABILITY OF ITS SOFTWARE ON EQUIPMENT THAT IS NOT SUPPLIED BY /DIGITAL. / / / / / / / / / / /THE RTS-8 CLOCK HANDLER ACCEPTS MESSAGES FROM THE USER AND INSERTS /ENTRIES INTO A CLOCK QUEUE. AS ENTRIES IN THE CLOCK QUEUE BECOME /DUE, THEY ARE REMOVED FROM THE QUEUE AND THE REQUEST ISS DECODED /AND EXECUTED. /THE CLOCK HANDLER MUST RUN IN FIELD 0 AS IT IS TREATED SPECIALLY /BY THE INTERRUPT CODE IN RTS-8 /THE FORMAT OF CLOCK MESSAGES ARE: /WORD 1 USED AS EVENT FLAG FOR MESSAGE /WORDS 2-3 USED BY RTS-8 /WORD 4 COMMAND WORD - BITS ARE: / BITS 0-2 FUNCTION: / 0 - SET EVENT FLAG AFTER TIMED INTERVAL / 1 - RUN SPECIFIED TASK AFTER INTERVAL / 2 - DERAIL SPECIIFIED TASK AFTER INTERVAL / 3 - RUN SPEC. TASK PERIODICALLY AFTER INTERVAL / 5,6, OR 7 - CANCEL ALL TIMED REQUESTS FOR SPECIFIED TASK / / BITS 5-11 SPECIFY TASK - 0 MEANS TASK IS SENDING TASK /WORD 5 HIGH ORDER OF TIME (IN TICKS) /WORD 6 LOW ORDER OF TIME /WORDS 7-8(OPT) DERAIL ADDRESS OR RESCHEDULE PERIOD /FORMAT OF CLOCK QUEUE ENTRY: /WORD 1 POINTER TO NEXT ENTRY (0 IF LAST) /WORD 2 AND 3 NUMBER OF TICKS FROM PREV ENTRY UNTIL THIS ONE - / NUMBER IS NEGATIVE, LOW ORDER IN WORD 2 /WORD 4 COMMAND WORD (FROM MESSAGE) /WORD 5 AND 6 WORDS 7 AND 8 OF MESSAGE (ADDR OF MESSAGE IF FN=0) /THIS CLOCK HANDLER WILL RUN ON MANY HARDWARE CONFIGURATIONS /THE PARAMETER "CLKTYP" CONTROLS THE CONFIGURATION /LEGAL VALUES OF CLKTYP ARE: / 0 DK8EA LINE CLOCK, DK8EC CRYSTAL CLOCK / 1 KW12A PROGRAMMABLE CLOCK / 2 VT8E CLOCK (INCLUDED WITH VT8E TERMINAL INTERFACE) / 3 DK8EP PROGRAMMABLE CLOCK / 4,6,10,ETC USER-DEFINED CLOCK TYPES /VARIOUS CLOCK IOT DEFINITIONS: IFZERO CLKTYP < CLSK= 6133 CLEI= 6131 CLDI= 6132 > IFNZRO CLKTYP&1 < /KW12 AND DK8EP IOT'S CLZE= 6130 /DK8EP ONLY! CLSK= 6131 CLLR= 6132 /CALLED CLDE ON DK8EP CLAB= 6133 CLEN= 6134 CLSA= 6135 > IFZERO CLKTYP-2 < CLSK= 6056 /VT8E INSTRUCTION "DPCL" DPGO= 6051 DPSM= 6052 /VT8E INSTRUCTIONS TO START AND STOP DISPLAY > IFNZRO CLKTYP&1 <HERTZ= 1750> /FORCE DK8EP,KW12 TO 1 KHZ TICKS= HERTZ%SHERTZ IFNZRO TICKS SHERTZ-HERTZ <RATERR, ERROR > IFZERO SHERTZ-300&4000 <TODERR, ERROR > /CLOCK TASK PAAMETERS: TASK= CLOCK INIWT= 0 CUR= 0 /** MUST RUN IN FIELD 0! ** FIELD 0 *10 /AUTO XR - NO-ONE ELSE SHOULD USE! CLKXR, 0 /MARK XR USED ON BITMAP /THIS IS THE CLOCK QUEUE CREATOR - IT IS INVOKED WHEN THE CODE /AT "CLKLP" NOTICES THAT THE INPUT MESSAGE QUEUE IS NON-EMPTY. ENDEXC= NTASKS+1 7+1200 *ENDEXC PAGE /START LOADING IN FIRST PG AFTER TASK TABLES GETMSG, CAL RECEIV /GET MESSAGE ADDRESS MADDR, 0 DCA MSGCDF /CDF IS IN AC ON RETURN XTRA1, /INITIALIZED IN CASE FUNCT IS "SET E.F." MSGCDF, HLT /SET TO DF OF MESSAGE AC7775 /SABVE ADDRESS OF MESSAGE EVENT FLAG TAD MADDR /IN XTRA2 - XTRA1&2 ARE NOW SET UP DCA XTRA2 /IN CASE COMMAND WAS "SET EVENT FLAG" TAD I MADDR /GET COMMAND AND (177 SNA CLA /CHECK FOR EXPLICIT TASK ARGUMENT TAD I XTRA2 /NONE - USE SENDING TASK AND (177 /(MESSAGE E.F. MAY HAVE 4000 BIT ON) TAD I MADDR DCA CLKCMD /SAVE CLOCK COMMAND TAD MSGCDF DCA CT /SET UP CDF OF EVENT FLAG IN "POST" CALL TAD MADDR DCA CLKXR /SET UP AUTO-XR FOR FETCHING ARGS TAD I CLKXR /GET HIGH ORDER INTERVAL DCA TH /SAVE IT TAD I CLKXR /GET LOW ORDER INTERVAL SNA /IF ZERO, MAKE IT 1 - THIS INTRODUCES A SMALL IAC /(LT .025%) ERROR IN SOME INTERVALS, BUT DCA TL /ELIMINATES THE KILLER 0 INTERVAL TAD CLKCMD /GET COMMAND RTL SNL SMA CLA /CHECK FOR "SET EVENT FLAG" COMMAND JMP NOIMEF /YES - SO DON'T SET EVENT FLAG NOW TAD I CLKXR /GET TWO MORE ARGUMENTS EVEN THOUGH WE DCA XTRA1 /ONLY NEED THEM FOR COMMANDS 2 AND 3. TAD I CLKXR DCA XTRA2 AC7775 /WE MUST FIGURE OUT WHERE THE TAD MADDR /MESSAGE STARTED SINCE WE DESTROYED XTRA2 CAL POST CT, 0 NOIMEF, JMS CLQINS /NOW INSERT THE MESSAGE INTO THE CLOCK QUEUE JMP I (CLKLP /SEARCH THE CLOCK QUEUE TO FIND WHERE TO PUT THIS REQUEST /THE REQUEST TO BE QUEUED SHOULD BE IN THE WORDS: /CLKCMD, TH, TL, XTRA1, XTRA2 CLQINS, 0 CDF CUR TAD (CLQ QSRCLP, DCA CQ TAD I CQ /GET NEXT QUEUE ENTRY DCA CT TAD CT DCA CLKXR /ACCESS BODY OF QUEUE ENTRY WITH AUTO-XR TAD I CT CLL /INHIBIT INTS WHILE LOOKING AT Q ENTRY IOF /TO KEEP IT FROM CHANGING ON US. SNA CLA /IS IT THE TERMINAL ONE? JMP INHERE /YES - INSERT HERE TAD I CLKXR TAD TL DCA TTL /SUBTRACT INTERVAL TO THIS QUEUED EVENT TAD CLKCMD /IF COMMAND IS NEGATIVE, SPA CLA /THIS IS NOT A REGULAR COMMAND BUT A CANCEL - JMP KILLQE /CHECK WHETHER WE SHOULD CANCEL THIS Q ENTRY TAD I CLKXR /FROM INTERVAL TO THE CURRENT REQUEST SNA /WATCH FOR 0 INTERVAL - SCREWS UP LINK JMP NULADD /NULL INTERVALS DON'T AFFECT SEARCH SZL CLL IAC /ADD IN CARRY AFTER ZERO TEST! TAD TH SNL /IF THE REQUEST OCCURS BEFORE THE CURRENT JMP INHERE /QUEUE ENTRY, BREAK THE QUEUE HERE DCA TH TAD TTL /SINCE QUEUED INTERVALS ARE CUMULATIVE, DCA TL /USE THE UPDATED INTERVAL FROM NOW ON NULADD, ION /ALLOW INTERRUPTS BETWEEN ENTRIES TAD CT JMP QSRCLP /GO TO NEXT QUEUE ENTRY KILLQE, AC0002 TAD CLKXR DCA MADDR /POINT AT COMMAND WORD OF QUEUE REQUEST TAD I MADDR CIA /COMPARE TASK NUMBER IN QUEUE ENTRY COMMAND TAD CLKCMD /TO SPECIFIED TASK AND (177 /(ONLY 7 BITS TO COMPARE SNA CLA /WELL? DCA I MADDR /MATCH - ZERO COMMAND WD (0 COMMAND IS NOP) JMP NULADD /FOUND WHERE IT GOES - NOW PUT IT THERE INHERE, DCA MADDR /SAVE HIGH ORDER OF DIFFERENCE TAD CLKCMD SPA CLA /IF THIS WAS A CANCEL COMMAND, JMP I (CLKLP /WE ARE DONE - DON'T INSERT ANYTHING. TAD CLF DCA I CQ /LINK THE FIRST ENTRY ON THE FREE LIST STA /INTO THE QUEUE AT THIS POINT TAD CLF /USE XR TO SET UP NEW ENTRY DCA CLKXR TAD I CLF /REMOVE FREE LIST ENTRY DCA CLF /FROM FREE LIST TAD CT /COMPLETE THE INSERTION BY SETTING UP DCA I CLKXR /THE POINTER TO THE NEXT QUEUE ENTRY TAD TL /PUT THE NEGATIVE OF THE INTERVAL CIA CLL /UNTIL THIS ENTRY IS EXECUTABLE INTO DCA I CLKXR /THE NEW QUEUE ENTRY, LOW ORDER CML RAL /WORD FIRST (FOR EASY INCREMENTING) ION /FINISHED DBL-PREC ARITHMETIC - ALLOW INTS TAD TH CIA DCA I CLKXR TAD CLKCMD DCA I CLKXR /PUT COMMAND WORD IN QUEUE ENTRY TAD XTRA1 DCA I CLKXR /AND EXTRA WORDS FOR COMMAND TAD XTRA2 DCA I CLKXR ISZ CT /NOW UPDATE THE FOLLOWING ENTRY TAD TTL /TO REFLECT THE REDUCED NUMBER DCA I CT /OF TICKS BETWEEN ENTRIES ISZ CT TAD MADDR /** WE MAY BE "UPDATING" ZROENT ** DCA I CT /** WE NEED TWO SCRATCH LOCS AFTER ZROENT ** JMP I CLQINS /RETURN ZROENT, 0 /PERMANENT FINAL ENTRY IN CLOCK QUEUE TH, 0 /TH AND TL ALSO SERVE AS THE FIRST TWO TL, 0 /WORDS OF "ZROENT" CQ, 0 XTRA2, 0 CLKCMD, 0 CLF, BEGFRE /INITIALIZED TO BEGINNING OF FREE LIST TTL, 0 PAGE /MAIN CLOCK HANDLER LOOP - SEE IF ANYTHING TO DO CLKEF, 4000+TASK /SIGNIFICANT TICK EVENT FLAG CLKWT, WAITM /SPECIAL MONITOR ENTRY TO WAIT EORMWT /FOR EVENT FLAG OR MESSAGE. CLKLP, IOF /INTERRUPTS OFF FOR DELICATE CODE! TAD CLKEF SNA CLA /SIGNIFICANT TICK? JMP GETICK /YES - PROCESS IT TAD I (CLF SZA CLA /ANY ROOM IN CLOCK QUEUE? TAD I (TASK 2+MSGTBL /YES - CONSIDER MESSAGES SNA CLA /CAN WE TAKE A MESSAGE? JMP CLKWT /NO - GO INTO EORMWT ION /YES - RESTORE INTERRUPTS JMP I (GETMSG /AND GO RECEIVE MESSAGE GETICK, TAD (4000+TASK /RESET EVENT FLAG DCA CLKEF /TO "WAITING" STATE ION /TURN INTERRUPTS BACK ON TAD CLIPTR /** GET POINTER FROM INTERRUPT ROUTINE ** DCA CLKXR /USE AUTO-XR TO ACCESS HIGH-ORDER WORD ISZ I CLKXR /OK, WE GOT A NIBBLE - BUMP HIGH-ORDER WORD JMP CLKLP /FALSE ALARM (SIGH) / BBBB OOO N N GGGGG / B B O O NN N G / BBBB O O N N N G GG - THE CLOCK HAS STRUCK! / B B O O N NN G G / BBBB OOO N N GGGGG CLKOV, TAD I CLQ /REMOVE THE FIRST ENTRY FROM THE CLOCK QUEUE DCA CLKTMP /AND PLACE IT ON THE FREE LIST. TAD I (CLF /THIS ALLOWS US TO PLAY WITH IT TO OUR DCA I CLQ /HEARTS CONTENT WITHOUT MISSING ANY TICKS TAD CLQ DCA I (CLF TAD CLKTMP DCA CLQ TAD I CLKXR SNA /CHECK FOR CANCELLED REQUEST JMP FIXQ /YES - JUST DELETE FROM QUEUE DCA I (CLKCMD TAD I (CLKCMD RTL /SET UP TO TEST BITS 1 AND 2 OF CMD WD SMA CLA /CHECK FOR COMMAND 1 OR 3 JMP NOTRUN /NO - 0 OR 2. SNL /WHICH ONE? JMP NORSCD /1 - STRAIGHT RUN COMMAND TAD I CLKXR DCA I (TH /GET RESCHEDULE INTERVAL TAD I CLKXR DCA I (TL TAD I (TH DCA I (XTRA1 /USE RESCHED INTERVAL AS NEW SCHEDULE TAD I (TL /AND RESCHEDULE INTERVAL DCA I (XTRA2 JMS I (CLQINS /INSERT THE NEW REQUEST IN THE CLOCK QUEUE NORSCD, TAD I (CLKCMD /GET TASK NUMBER AND (177 /OUT OF COMMAND WORD CAL RUN /AND RUN THE JOB NOW. JMP FIXQ /CLEAN UP THE QUEUE ENTRY /TEST FOR DERAIL REQUEST NOTRUN, TAD I CLKXR /LOAD ARGUMENT INTO AC SNL /DERAIL OR EVENT-FLAG REQUEST? JMP SETEF /EVENT FLAG DCA DRLADR /SAVE DERAIL SUBROUTINE ADDRESS TAD I (CLKCMD AND (177 /GET TASK NUMBER FROM COMMAND WORD CAL DERAIL /DERAIL THE TASK CLKTMP, DRLADR, 0 JMP FIXQ SETEF, DCA EFCDF /SAVE DATA FIELD OF EVENT FLAG TAD I CLKXR /GET ADDRESS OF EVENT FLAG CAL POST /POST THE EVENT FLAG ASSOCIATED EFCDF, 0 /WITH THIS TIMER REQUEST FIXQ, CLA IAC TAD CLQ DCA CLKXR /IT IS POSSIBLE FOR THE INTERVAL TAD I CLKXR /BETWEEN EVENTS ON THE QUEUE TO BE 0 - SNA CLA /THIS MEANS THE EVENTS COME UP SIMULTANEOUSLY. TAD I CLQ /WE MUST CHECK FOR SIMULTANEITY HERE SNA CLA /(WATCHING OUT FOR THE END OF THE QUEUE!) JMP CLKLP /IF NONE, GO WAIT FOR THE NEXT TICK JMP CLKOV /SIMULTANEOUS REQUEST - GO PROCESS IT /CLOCK INTERRUPT ROUTINE /INSERT CONDITIONALIZED FLAG CLEARS FOR USER-DEFINED CLOCK HERE. CLKINT, IFNZRO CLKTYP&1 <CLSA> /CLEAR KW12/DK8EP FLAG IFZERO CLKTYP&1 < IFNZRO TICKS-1 < ISZ CLKCNT /COUNT CLOCK TICKS PER SOFTWARE TICK POSTDS /UNLESS COUNT=1 - THEN WHY BOTHER? TAD (-TICKS /RESTORE FULL COUNT DCA CLKCNT > > CLA IAC /** AC MAY NOT BE 0 HERE IF KW12 OR DK8EP ** TAD CLQ /SAVE POINTER TO LOW-ORDER TICK COUNT DCA CLIPTR /OF FIRST QUEUE ENTRY ISZ TODL JMP CLKQT /BUMP TIME-OF-DAY ISZ TODH JMP CLKQT TAD MIDNTH /T.O.D. CLOCK OVERFLOWS AT MIDNIGHT - DCA TODH /WE MUST RESET TO A SPECIAL FUDGE TO TAD MIDNTL /ASSURE THAT IT WILL HAPPEN AGAIN DCA TODL /NEXT MIDNIGHT. TAD DATE TAD (10 DCA DATE /BUMP DATE 1 DAY, THE CRUDE WAY CLKQT, TAD I CLQ SZA CLA /IF QUEUE IS NOT EMPTY, ISZ I CLIPTR /BUMP LOW-ORDER COUNT POSTDS /NOTHING DOING TAD (CLKEF /SET EVENT FLAG TO START DEQUEUER RUNNING POSTDS /AS WE MAY HAVE REACHED A SIGNIFICANT TIME CLIPTR, 0 /INTERRUPT-LEVEL POINTER CLQ, ZROENT /QUEUE INITIALLY EMPTY IFNZRO TICKS-1 < CLKCNT, -TICKS > DAYL= 600 SHERTZ /THESE STATEMENTS COMPUTE THE NUMBER OF TICKS DAYH= 6 SHERTZ%100 /IN A DAY AS A DOUBLE WORD QUANTITY DAYH= 25 SHERTZ+DAYH / = 250600*SHERTZ IFNZRO DAYL <DAYH=DAYH+1> /JUST FOR BORROW ON NEGATE MIDNTH, -DAYH MIDNTL, -DAYL PAGE /CLOCK QUEUE FREE LIST - ALSO INITIALIZATION CODE EXROOM= ENDEXC+177&7600-ENDEXC /CALCULATE ROOM IN PAGE WITH EXEC TABLES IFNZRO CLKQLN 6-EXROOM&4000 < /IF QUEUE WILL FIT THERE, IFNZRO 100-EXROOM&4000 < /AS WELL AS INITIALIZATION CODE, *ENDEXC /THEN SAVE SOME SPACE > > BEGFRE, START, IOF /IOF WHEN MESSING WITH SKIP CHAIN!! ISZ DATE /DATE CONTAINS POINTER TO CLOCK SKIP LOC -1 TAD (CLSK DCA I DATE TAD DATE TAD (4 DCA DATE TAD (CLKINT DCA I DATE CDF 10 TAD I (7666 /GET OS/8 DATE WORD DCA DATE /SET RTS DATE FROM IT CDF CUR TAD I (MIDNTH DCA TODH /SET TIME TO MIDNIGHT (AS GOOD AS ANY TIME) TAD I (MIDNTL DCA TODL /INSERT CONDITIONALIZED INITIALIZATION CODE FOR USER-DEFINED /CLOCK HERE - MUST ENABLE INTERRUPTS AND SET RATE. IFZERO CLKTYP < CLEI /ENABLE CLOCK INTERRUPTS FOR DK8EA,C > IFZERO CLKTYP-3 < /SPECIFIC DK8EP INIT CODE STA CLZE /ZERO COMMAND REGISTER ON DK8EP TAD (5311-4100 /5310 = ENABLE INTS, 1 KHZ, MODE 1 > IFNZRO CLKTYP&1 < /COMMON DK8EP, KW12 INIT CODE TAD (4100 /4100 = 1 KHZ, MODE 1 CLLR /LOAD COMMAND REGISTER CLA /CLLR DOESN'T CLEAR AC TAD (-TICKS CLAB /SCALE DOWN CLOCK TO SOFTWARE RATE CLA /DOES NOT CLEAR AC > IFZERO CLKTYP-1 < /SPECIFIC KW12 INIT CODE TAD (300 /FORCE CLOCK BUFFER INTO COUNTER AND CLEN /ENABLE KW12 INTERRUPTS CLA /THIS DOESN'T CLEAR AC EITHER > IFZERO CLKTYP-2 < /VT8E INIT CODE CLA IAC DPGO /START VT8E AT A RANDOM ADDRESS, DPSM /ENABLING INTERRUPTS - THEN STOP IT IMMEDIATELY CLA /(JUST IN CASE) > JMP FREELP /CLOCK QUEUE INITIALIZATION - /THIS CODE IS WRITTEN TO SKIP EVERY SIXTH WORD SINCE IT IS /SETTING THESE WORDS TO QUEUE POINTERS. /** NO LITERALS IN THIS CODE! ** ZBLOCK .-BEGFRE%6 6+BEGFRE+7-. /MOVE US TO THE 2ND WORD OF A 6 WD BLOCK K FREELP, TAD FREPTR TAD F6 DCA I FREPTR /CHAIN EACH QUEUE ENTRY TO THE NEXT ONE TAD FREPTR SKP 0 /THIS LOC GETS DESTROYED BY OUR LOOP! TAD FRELIM SMA CLA JMP INIXIT /DONE - END INITIALIZATION CODE TAD I FREPTR /GET NEW QUEUE ENTRY ADDRESS SKP 0 DCA FREPTR JMP FREELP INIXIT, DCA I FREPTR /ZERO LAST POINTER ION JMP I PCLKLP /START WAITING FOR CLOCK TICKS 0 FREPTR, BEGFRE F6, 6 FRELIM, 13-ENDFRE /SO WE NEVER GO PAST "ENDFRE" PCLKLP, CLKLP PAGE IFZERO CLKQLN 6+BEGFRE-.&4000 < ZBLOCK CLKQLN 6+BEGFRE-.+5 /+5 FOR SAFETY > /MAKE SPACE FOR ENTRIES IF MORE THAN 21 DESIRED ENDFRE= . $$$