# Copyright: Public domain. # Filename: WAITLIST.agc # Purpose: Part of the source code for Colossus 2A, AKA Comanche 055. # It is part of the source code for the Command Module's (CM) # Apollo Guidance Computer (AGC), for Apollo 11. # Assembler: yaYUL # Contact: Ron Burkey . # Website: www.ibiblio.org/apollo. # Pages: 1221-1235 # Mod history: 2009-05-14 RSB Adapted from the Colossus249/ file of the # same name, using Comanche055 page images. # # This source code has been transcribed or otherwise adapted from digitized # images of a hardcopy from the MIT Museum. The digitization was performed # by Paul Fjeld, and arranged for by Deborah Douglas of the Museum. Many # thanks to both. The images (with suitable reduction in storage size and # consequent reduction in image quality as well) are available online at # www.ibiblio.org/apollo. If for some reason you find that the images are # illegible, contact me at info@sandroid.org about getting access to the # (much) higher-quality images which Paul actually created. # # Notations on the hardcopy document read, in part: # # Assemble revision 055 of AGC program Comanche by NASA # 2021113-051. 10:28 APR. 1, 1969 # # This AGC program shall also be referred to as # Colossus 2A # Page 1221 # PROGRAM DESCRIPTION DATE - 10 OCTOBER 1966 # MOD NO - 2 LOG SECTION - WAITLIST # MOD BY - MILLER (DTMAX INCREASED TO 162.5 SEC) ASSEMBLY SUNBURST REV 5 # MOD 3 BY KERNAN (INHINT INSERTED AT WAITLIST) 2/28/68 SKIPPER REV 4 # MOD 4BY KERNAN (TWIDDLE IN 54) 3/28/68 SKIPPER REV 13. # # FUNCTIONAL DESCRIPTION- # PART OF A SECTION OF PROGRAMS,-WAITLIST, TASKOVER, T3RUPT, USED TO CALL A PROGRAM, (CALLED A TASK), # WHICH IS TO BEGIN IN C(A) CENTISECONDS. WAITLIST UPDATES TIME3, LST1 AND LST2. THE MEANING OF THESE LISTS # FOLLOW. # # C(TIME3) = 16384 -(T1-T) CENTISECONDS, (T=PRESENT TIME, T1-TIME FOR TASK1) # # C(LST1) = -(T2-T1)+1 # C(LST1 +1) = -(T3-T2)+1 # C(LST1 +2) = -(T4-T3)+1 # ... # C(LST1 +6) = -(T8-T7)+1 # C(LST1 +7) = -(T9-T8)+1 # # C(LST2) = 2CADR OF TASK1 # C(LST2 +2) = 2CADR OF TASK2 # ... # C(LST2 +14) = 2CADR OF TASK8 # C(LST2 +16) = 2CADR OF TASK9 # # WARNINGS- # -------- # 1) 1 <= C(A) <= 16250D (1 CENTISECOND TO 162.5 SEC) # 2) 9 TASKS MAXIMUM # 3) TASKS CALLED UNDER INTERRUPT INHIBITED # 4) TASKS END BY TC TASKOVER # # CALLING SEQUENCE- # # L-1 CA DELTAT (TIME IN CENTISECONDS TO TASK START) # L TC WAITLIST # L+1 2CADR DESIRED TASK # L+2 (MINOR OF 2CADR) # L+3 RELINT (RETURNS HERE) # # TWIDDLE- # ------- # TWIDDLE IS FOR USE WHEN THE TASK BEING SET UP IS IN THE SAME EBANK AND FBANK AS THE USER. IN # SUCH CASES, IT IMPROVES UPON WAITLIST BY ELIMINATING THE NEED FOR THE BBCON HALF OF THE 2CADR, # Page 1222 # SAVING A WORD. TWIDDLE IS LIKE WAITLIST IN EVERY RESPECT EXCEPT CALLING SEQUENCE, TO WIT- # # L-1 CA DELTAT # L TC TWIDDLE # L+1 ADRES DESIRED TASK # L+2 RELINT (RETURNS HERE) # # NORMAL EXIT MODES- # # AT L+3 OF CALLING SEQUENCE # # ALARM OR ABORT EXIT MODES- # # TC ABORT # OCT 1203 (WAITLIST OVERFLOW - TOO MANY TASKS) # # ERASABLE INITIALIZATION REQUIRED- # # ACCOMPLISHED BY FRESH START,-- LST2,..., LST2 +16 =ENDTASK # LST1,..., LST1 +7 =NEG1/2 # # OUTPUT-- # # LST1 AND LST2 UPDATED WITH NEW TASK AND ASSOCIATED TIME. # DEBRIS- # CENTRALS- A,Q,L # OTHER - WAITEXIT, WAITADR, WAITTEMP, WAITBANK # DETAILED ANALYSIS OF TIMING- # # CONTROL WILL NOT BE RETURNED TO THE SPECIFIED ADDRESS (2CADR) IN EXACTLY DELTA T CENTISECONDS. # THE APPROXIMATE TIME MAY BE CALCULATED AS FOLLOWS # # LET T0 = THE TIME OF THE TC WAITLIST # LET TS = T0 +147U + COUNTER INCREMENTS (SET UP TIME) # LET X = TS -(100TS)/100 (VARIANCE FROM COUNTERS) # LET Y = LENGTH OF TIME OF INHIBIT INTERRUPT AFTER T3RUPT # LET Z = LENGTH OF TIME TO PROCESS TASKS WHICH ARE DUE THIS T3RUPT BUT DISPATCHED EARLIER. # (Z=0, USUALLY) # LET DELTD = THE ACTUAL TIME TAKEN TO GIVE CONTROL TO 2CADR # THEN DELTD = TS+DELTA T -X +Y +Z +1.05MS* +COUNTERS* # *THE TIME TAKEN BY WAITLIST ITSELF AND THE COUNTER TICKING DURING THIS WAITLIST TIME. # # IN SHORT, THE ACTUAL TIME TO RETURN CONTROL TO A 2CADR IS AUGMENTED BY THE TIME TO SET UP THE TASK'S # INTERRUPT, ALL COUNTERS TICKING, THE T3RUPT PROCESSING TIME, THE WAITLIST PROCESSING TIME AND THE POSSIBILITY # OF OTHER TASKS INHIBITING THE INTERRUPT. BLOCK 02 # Page 1223 EBANK= LST1 # TASK LISTS IN SWITCHED E BANK. COUNT 02/WAIT TWIDDLE INHINT TS L # SAVE DELAY TIME IN L CA POSMAX ADS Q # CREATING OVERFLOW AND Q-1 IN Q CA BBANK EXTEND ROR SUPERBNK XCH L WAITLIST INHINT EXTEND BZMF WATLST0- XCH Q # SAVE DELTA T IN Q AND RETURN IN TS WAITEXIT # WAITEXIT. EXTEND INDEX WAITEXIT # IF TWIDDLING, THE TS SKIPS TO HERE DCA 0 # PICK UP 2CADR OF TASK. -1 TS WAITADR # BBCON WILL REMAIN IN L DLY2 CAF WAITBB # ENTRY FROM FIXDELAY AND VARDELAY. XCH BBANK TCF WAIT2 WATLST0- TC POODOO OCT 1204 # WAITLIST CALL WITH ZERO OR NEG DT # RETURN TO CALLER AFTER TASK INSERTION: LVWTLIST DXCH WAITEXIT AD TWO DTCB EBANK= LST1 WAITBB BBCON WAIT2 # RETURN TO CALLER +2 AFTER WAITING DT SPECIFIED AT CALLER +1. FIXDELAY INDEX Q # BOTH ROUTINES MUST BE CALLED UNDER CAF 0 # WAITLIST CONTROL AND TERMINATE THE TASK INCR Q # IN WHICH THEY WERE CALLED. # RETURN TO CALLER +1 AFTER WAITING THE DT AS ARRIVING IN A. VARDELAY XCH Q # DT TO Q. TASK ADRES TO WAITADR. TS WAITADR CA BBANK # BBANK IS SAVED DURING DELAY. EXTEND # Page 1224 ROR SUPERBNK # ADD SBANK TO BBCON. TS L CAF DELAYEX TS WAITEXIT # GO TO TASKOVER AFTER TASK ENTRY. TCF DLY2 DELAYEX TCF TASKOVER -2 # RETURNS TO TASKOVER # Page 1225 # ENDTASK MUST ENTERED IN FIXED-FIXED SO IT IS DISTINGUISHABLE BY ITS ADRES ALONE. EBANK= LST1 ENDTASK -2CADR SVCT3 SVCT3 CCS FLAGWRD2 # DRIFT FLAG TCF TASKOVER TCF TASKOVER TCF +1 CCS IMUCADR # DON'T DO NBDONLY IF SOMEONE ELSE IS IN TCF SVCT3X TCF +3 TCF SVCT3X TCF SVCT3X +3 CAF PRIO35 # COMPENSATE FOR NBD COEFFICIENTS ONLY. TC NOVAC # ENABLE EVERY 81.93 SECONDS EBANK= NBDX 2CADR NBDONLY TCF TASKOVER SETLOC FFTAG6 BANK SVCT3X TC FIXDELAY # DELAY MAX OF 2 TIMES FOR IMU ZERO DEC 500 TC SVCT3 # CHECK DRIFT FLAG AGAIN # Page 1226 # BEGIN TASK INSERTION. BANK 01 COUNT 01/WAIT WAIT2 TS WAITBANK # BBANK OF CALLING PROGRAM. CS TIME3 AD BIT8 # BIT 8 = OCT 200 CCS A # TEST 200 - C(TIME3). IF POSITIVE, # IT MEANS THAT TIME3 OVERFLOW HAS OCCURRED PRIOR TO CS TIME3 AND THAT # C(TIME3) = T - T1, INSTEAD OF 1.0 - (T1 - T). THE FOLLOWING FOUR # ORDERS SET C(A) = TD - T1 + 1 IN EITHER CASE. AD OCT40001 # OVERFLOW HAS OCCURRED. SET C(A) = CS A # T - T1 + 1.0 - 201 # NORMAL CASE (C(A) NNZ) YIELDS SAME C(A): -( -(1.0-(T1-T)) + 200) - 1 AD OCT40201 AD Q # RESULT = TD - T1 + 1. CCS A # TEST TD - T1 + 1 AD LST1 # IF TD - T1 POS, GO TO WTLST5 WITH TCF WTLST5 # C(A) = (TD - T1) + C(LST1) = TD-T2+1 NOOP CS Q # NOTE THAT THIS PROGRAM SECTION IS NEVER ENTERED WHEN T-T1 G/E -1, # SINCE TD-T1+1 = (TD-T) + (T-T1+1), AND DELTA T = TD-T G/E +1. (G/E # SYMBOL MEANS GREATER THAN OR EQUAL TO). THUS THERE NEED BE NO CON- # CERN OVER A PREVIOUS OR IMMINENT OVERFLOW OF TIME3 HERE. AD POS1/2 # WHEN TD IS NEXT, FORM QUANTITY AD POS1/2 # 1.0 - DELTA T = 1.0 - (TD - T) XCH TIME3 AD NEGMAX AD Q # 1.0 - DELTAT T NOW COMPLETE. EXTEND # ZERO INDEX Q. QXCH 7 # (ZQ) # Page 1227 WTLST4 XCH LST1 XCH LST1 +1 XCH LST1 +2 XCH LST1 +3 XCH LST1 +4 XCH LST1 +5 XCH LST1 +6 XCH LST1 +7 CA WAITADR # (MINOR PART OF TASK CADR HAS BEEN IN L.) INDEX Q TCF +1 DXCH LST2 DXCH LST2 +2 DXCH LST2 +4 DXCH LST2 +6 DXCH LST2 +8D DXCH LST2 +10D # AT END, CHECK THAT C(LST2 +10) IS STD DXCH LST2 +12D DXCH LST2 +14D DXCH LST2 +16D AD ENDTASK # END ITEM, AS CHECK FOR EXCEEDING # THE LENGTH OF THE LIST. EXTEND # DUMMY TASK ADRES SHOULD BE IN FIXED- BZF LVWTLIST # FIXED SO ITS ADRES ALONE DISTINGUISHES TCF WTABORT # IT. # Page 1228 WTLST5 CCS A # TEST TD - T2 + 1 AD LST1 +1 TCF +4 AD ONE TC WTLST2 OCT 1 +4 CCS A # TEST TD - T3 + 1 AD LST1 +2 TCF +4 AD ONE TC WTLST2 OCT 2 +4 CCS A # TEST TD - T4 + 1 AD LST1 +3 TCF +4 AD ONE TC WTLST2 OCT 3 +4 CCS A # TEST TD - T5 + 1 AD LST1 +4 TCF +4 AD ONE TC WTLST2 OCT 4 +4 CCS A # TEST TD - T6 + 1 AD LST1 +5 TCF +4 AD ONE TC WTLST2 OCT 5 +4 CCS A # TEST TD - T7 + 1 AD LST1 +6 TCF +4 AD ONE TC WTLST2 OCT 6 # Page 1229 +4 CCS A AD LST1 +7 TCF +4 AD ONE TC WTLST2 OCT 7 +4 CCS A WTABORT TC BAILOUT # NO ROOM IN THE INN. OCT 1203 AD ONE TC WTLST2 OCT 10 OCT40201 OCT 40201 # Page 1230 # THE ENTRY TO WTLST2 JUST PRECEDING OCT N IS FOR T LE TD LE T -1. # N N+1 # # (LE MEANS LESS THAN OR EQUAL TO). AT ENTRY, C(A) = -(TD - T + 1) # N+1 # # THE LST1 ENTRY-(T -T +1) IS TO BE REPLACED BY -(TD - T + 1), AND # N+1 N N # # THE ENTRY-(T - TD + 1) IS TO BE INSERTED IMMEDIATELY FOLLOWING. # N+1 WTLST2 TS WAITTEMP # C(A) = -(TD - T + 1) INDEX Q CAF 0 TS Q # INDEX VALUE INTO Q. CAF ONE AD WAITTEMP INDEX Q # C(A) = -(TD - T ) + 1. ADS LST1 -1 # N CS WAITTEMP INDEX Q TCF WTLST4 # Page 1231 # ENTERS HERE ON T3 RUPT TO DISPATCH WAITLISTED TASK. T3RUPT EXTEND ROR SUPERBNK # READ CURRENT SUPERBANK VALUE AND TS BANKRUPT # SAVE WITH E AND F BANK VALUES. EXTEND QXCH QRUPT T3RUPT2 CAF NEG1/2 # DISPATCH WAITLIST TASK. XCH LST1 +7 XCH LST1 +6 XCH LST1 +5 XCH LST1 +4 # 1. MOVE UP LST1 CONTENTS, ENTERING XCH LST1 +3 # A VALUE OF 1/2 +1 AT THE BOTTOM XCH LST1 +2 # FOR T6-T5, CORRESPONDING TO THE XCH LST1 +1 # INTERVAL 81.91 SEC FOR ENDTASK. XCH LST1 AD POSMAX # 2. SET T3 = 1.0 - T2 - T USING LIST 1. ADS TIME3 # SO T3 WONT TICK DURING UPDATE. TS RUPTAGN CS ZERO TS RUPTAGN # SETS RUPTAGN TO +1 ON OVERFLOW. EXTEND # DISPATCH TASK. DCS ENDTASK DXCH LST2 +16D DXCH LST2 +14D DXCH LST2 +12D DXCH LST2 +10D DXCH LST2 +8D DXCH LST2 +6 DXCH LST2 +4 DXCH LST2 +2 DXCH LST2 XCH L EXTEND WRITE SUPERBNK # SET SUPERBANK FROM BBCON OF 2CADR XCH L # RESTORE TO L FOR DXCH Z. DTCB # Page 1232 # RETURN, AFTER EXECUTION OF T3 OVERFLOW TASK: BLOCK 02 COUNT 02/WAIT TASKOVER CCS RUPTAGN # IF +1 RETURN TO T3RUPT, IF -0 RESUME. CAF WAITBB TS BBANK TCF T3RUPT2 # DISPATCH NEXT TASK IF IT WAS DUE. CA BANKRUPT EXTEND WRITE SUPERBNK # RESTORE SUPERBANK BEFORE RESUME IS DONE RESUME EXTEND QXCH QRUPT NOQRSM CA BANKRUPT XCH BBANK NOQBRSM DXCH ARUPT RELINT RESUME # Page 1233 # LONGCALL # # PROGRAM DESCRIPTION DATE- 17 MARCH 1967 # PROGRAM WRITTEN BY W.H. VANDEVER LOG SECTION WAITLIST # MOD BY- R. MELANSON TO ADD DOCUMENTATION ASSEMBLY SUNDISK REV. 100 # # FUNCTIONAL DESCRIPTION- # LONGCALL IS CALLED WITH THE DELTA TIME ARRIVING IN A,L SCALED AS TIME2,TIME1 WITH THE 2CADR OF THE TASK # IMMEDIATELY FOLLOWING THE TC LONGCALL. FOR EXAMPLE, IT MIGHT BE DONE AS FOLLOWS WHERE TIMELOC IS THE NAME OF # A DP REGISTER CONTAINING A DELTA TIME AND WHERE TASKTODO IS THE NAME OF THE LOCATION AT WHICH LONGCALL IS TO # START # # CALLING SEQUENCE- # EXTEND # DCA TIMELOC # TC LONGCALL # 2CADR TASKTODO # # NORMAL EXIT MODE- # 1). TC WAITLIST # 2). DTCB (TC L+3 OF CALLING ROUTINE 1ST PASS THRU LONGCYCL) # 3). DTCB (TO TASKOVER ON SUBSEQUENT PASSES THRU LONGCYCL) # # ALARM OR ABORT EXIT MODE- # NONE # # OUTPUT- # LONGTIME AND LONGTIME+1 = DELTA TIME # LONGEXIT AND LONGEXIT+1 = RETURN 2CADR # LONGCADR AND LONGCADR+1 = TASK 2CADR # A = SINGLE PRECISION TIME FOR WAITLIST # # ERASABLE INITIALIZATION- # A = MOST SIGNIFICANT PART OF DELTA TIME # L = LEAST SIGNIFICANT PART OF DELTA TIME # Q = ADDRESS OF 2CADR TASK VALUE # # DEBRIS- # A,Q,L # LONGCADR AND LONGCADR+1 # LONGEXIT AND LONGEXIT+1 # LONGTIME AND LONGTIME+1 # # *** THE FOLLOWING IS TO BE IN FIXED-FIXED AND UNSWITCHED ERRASIBLE *** BLOCK 02 EBANK= LST1 LONGCALL DXCH LONGTIME # OBTAIN THE DELTA TIME EXTEND # OBTAIN THE 2CADR # Page 1234 NDX Q DCA 0 DXCH LONGCADR EXTEND # NOW GO TO THE APPROPRIATE SWITCHED BANK DCA LGCL2CDR # FOR THE REST OF LONGCALL DTCB EBANK= LST1 LGCL2CDR 2CADR LNGCALL2 # *** THE FOLLOWING MAY BE IN A SWITCHED BANK, INCLUDING ITS ERASABLE *** BANK 01 COUNT 01/WAIT LNGCALL2 LXCH LONGEXIT +1 # SAVE THE CORRECT BB FOR RETURN CA TWO # OBTAIN THE RETURN ADDRESS ADS Q TS LONGEXIT # *** WAITLIST TASK LONGCYCL *** LONGCYCL EXTEND # CAN WE SUCCESFULLY TAKE ABOUT 1.25 DCS DPBIT14 # MINUTES OFF OF LONGTIME DAS LONGTIME CCS LONGTIME +1 # THE REASONING BEHIND THIS PART IS TCF MUCHTIME # INVOLVED, TAKING INTO ACCOUNT THAT THE # WORDS MAY NOT BE SIGNED CORRECTED (DP # BASIC INSTRUCTIONS # DO NOT SIGN CORRECT) AND THAT WE SUBTRAC- # TED BIT14 (1 OVER HALF THE POS. VALUE # REPRESENTABLE IN SINGLE WORD) NOOP # CAN'T GET HERE ********** TCF +1 CCS LONGTIME TCF MUCHTIME DPBIT14 OCT 00000 OCT 20000 # LONGCALL LASTTIME CA BIT14 # GET BACK THE CORRECT DELTA TFOR WAITLIST ADS LONGTIME +1 TC WAITLIST EBANK= LST1 2CADR GETCADR # THE ENTRY TO OUR LONGCADR LONGRTRN CA TSKOVCDR # SET IT UP SO THAT ONLY THE FIRST EXIT IS # Page 1235 DXCH LONGEXIT # TO THE CALLER OF LONGCALL DTCB # THE REST ARE TO TASKOVER MUCHTIME CA BIT14 # WE HAVE OVER OUR ABOUT 1.25 MINUTES TC WAITLIST # SO SET UP FOR ANOTHER CYCLE THROUGH HERE EBANK= LST1 2CADR LONGCYCL TCF LONGRTRN # NOW EXIT PROPERLY # *** WAITLIST TASK GETCADR *** GETCADR DXCH LONGCADR # GET THE LONGCALL THAT WE WISHED TO START DTCB # AND TRANSFER CONTROL TO IT TSKOVCDR GENADR TASKOVER