Source Code

These source-code files are part of a reconstructed copy of Comanche 051, the original release of the Apollo 11 Command Module (CM) Apollo Guidance Computer (AGC) software.

The reconstruction began with source code of Comanche 055 previously transcribed from a digitized copy of that program. The code was then updated by undoing changes related to the R-2 lunar potential model, using hints from program comments and change-indicating asterisks in the Comanche 055 listing as a guide. The reconstruction was verified by matching memory-bank checksums to those listed in drawing 2021153D. Note that page numbers in the reconstructed code match those on the Comanche 055 printout, although the added code would likely have changed page numbers for a real Comanche 051 listing.

Comments from the original source code are prefixed with a single '#' symbol, whereas comments added later are prefixed by "##" or "###". Report any errors noted by creating an issue report at the Virtual AGC project's GitHub repository.

047814,000002:                                                                                                  ## Copyright:   Public domain.
047815,000003:                                                                                                  ## Filename:    INTER-BANK_COMMUNICATION.agc
047816,000004:                                                                                                  ## Purpose:     A section of Comanche revision 051.
047817,000005:                                                                                                  ##              It is part of the reconstructed source code for the
047818,000006:                                                                                                  ##              original release of the flight software for the Command
047819,000007:                                                                                                  ##              Module's (CM) Apollo Guidance Computer (AGC) for Apollo 11.
047820,000008:                                                                                                  ##              The code has been recreated from a copy of Comanche 055. It
047821,000009:                                                                                                  ##              has been adapted such that the resulting bugger words
047822,000010:                                                                                                  ##              exactly match those specified for Comanche 51 in NASA drawing
047823,000011:                                                                                                  ##              2021153D, which gives relatively high confidence that the
047824,000012:                                                                                                  ##              reconstruction is correct.
047825,000013:                                                                                                  ## Reference:   pp. 1103-1106
047826,000014:                                                                                                  ## Assembler:   yaYUL
047827,000015:                                                                                                  ## Contact:     Ron Burkey <info@sandroid.org>.
047828,000016:                                                                                                  ## Website:     www.ibiblio.org/apollo/index.html
047829,000017:                                                                                                  ## Mod history: 2019-07-30 MAS  Created from Comanche 55.
047830,000018: 

Page 1103

047832,000020:                                                                                                  #  THE FOLLOWING ROUTINE CAN BE USED TO CALL A SUBROUTINE IN ANOTHER BANK. IN THE BANKCALL VERSION, THE
047833,000021:                                                                                                  #  CADR OF THE SUBROUTINE IMMEDIATELY FOLLOWS THE TC BANKCALL INSTRUCTION, WITH C(A) AND C(L) PRESERVED.
047834,000022: 
047835,000023:    4662                                           BLOCK    02                                    
047836,000024:    4662                                           COUNT    02/BANK                               
047837,000025: 
047838,000026:    4662           52134        BANKCALL           DXCH     BUF2                                  #  SAVE INCOMING A,L.
047839,000027:    4663           50002                           INDEX    Q                                     #  PICK UP CADR.
047840,000028:    4664           30000                           CA       0                                     
047841,000029:    4665           24002                           INCR     Q                                     #  SO WE RETURN TO THE LOC. AFTER THE CADR.
047842,000030: 
047843,000031:                                                                                                  #  SWCALL IS  IDENTICAL TO BANKCALL, EXCEPT THAT THE CADR ARRIVES IN A.
047844,000032: 
047845,000033:    4666           54001        SWCALL             TS       L                                     
047846,000034:    4667           22004                           LXCH     FBANK                                 #  SWITCH BANKS, SAVING RETURN.
047847,000035:    4670           75054                           MASK     LOW10                                 #  GET SUB-ADDRESS OF CADR.
047848,000036:    4671           56002                           XCH      Q                                     #  A,L NOW CONTAINS DP RETURN.
047849,000037:    4672           52134                           DXCH     BUF2                                  #  RESTORING INPUTS IF THIS IS A BANKCALL.
047850,000038:    4673           50002                           INDEX    Q                                     
047851,000039:    4674           02000                           TC       10000                                 #  SETTING Q TO SWRETURN.
047852,000040: 
047853,000041:    4675           56134        SWRETURN           XCH      BUF2       +1                         #  COMES HERE TO RETURN TO CALLER. C(A,L)
047854,000042:    4676           56004                           XCH      FBANK                                 #  ARE PRESERVED FOR RETURN.
047855,000043:    4677           56134                           XCH      BUF2       +1                         
047856,000044:    4700           00133                           TC       BUF2                                  
047857,000045: 
047858,000046:                                                                                                  #  THE FOLLOWING ROUTINE CAN BE USED AS A UNILATERAL JUMP WITH C(A,L) PRESERVED AND THE CADR IMMEDIATELY
047859,000047:                                                                                                  #  FOLLOWING THE TC POSTJUMP INSTRUCTION.
047860,000048: 
047861,000049:    4701           56002        POSTJUMP           XCH      Q                                     #  SAVE INCOMING C(A).
047862,000050:    4702           50000                           INDEX    A                                     #  GET CADR.
047863,000051:    4703           30000                           CA       0                                     
047864,000052: 
047865,000053:                                                                                                  #  BANKJUMP IS THE SAME AS POSTJUMP, EXCEPT THAT THE CADR ARRIVES IN A.
047866,000054: 
047867,000055:    4704           54004        BANKJUMP           TS       FBANK                                 
047868,000056:    4705           75054                           MASK     LOW10                                 
047869,000057:    4706           56002                           XCH      Q                                     #  RESTORING INPUT C(A) IF THIS WAS A
047870,000058:    4707           50002        Q+10000            INDEX    Q                                     #  POSTJUMP.
047871,000059:    4710           12000        PRIO12             TCF      10000                                 #  PRIO12 = TCF  10000 = 12000
047872,000060: 

Page 1104

047874,000062:                                                                                                  #  THE FOLLOWING ROUTINE GETS THE RETURN CADR SAVED BY SWCALL OR BANKCALL AND LEAVES IT IN A.
047875,000063: 
047876,000064:    4711           35054        MAKECADR           CAF      LOW10                                 
047877,000065:    4712           70133                           MASK     BUF2                                  
047878,000066:    4713           60134                           AD       BUF2       +1                         
047879,000067:    4714           00002                           TC       Q                                     
047880,000068: 
047881,000069:    4715           54135        SUPDACAL           TS       MPTEMP                                
047882,000070:    4716           56004                           XCH      FBANK                                 #  SET FBANK FOR DATA.
047883,000071:    4717           00006                           EXTEND                                         
047884,000072:    4720           04007                           ROR      SUPERBNK                              #  SAVE FBANK IN BITS 15-11, AND
047885,000073:    4721           56135                           XCH      MPTEMP                                #  SUPERBANK IN BITS 7-5.
047886,000074:    4722           75054                           MASK     LOW10                                 
047887,000075:    4723           56001                           XCH      L                                     #  SAVE REL. ADR. IN BANK, FETCH SUPERBITS.
047888,000076:    4724           00004                           INHINT                                         #  BECAUSE RUPT DOES NOT SAVE SUPERBANK.
047889,000077:    4725           00006                           EXTEND                                         
047890,000078:    4726           01007                           WRITE    SUPERBNK                              #  SET SUPERBANK FOR DATA.
047891,000079:    4727           50001                           INDEX    L                                     
047892,000080:    4730           32000                           CA       10000                                 #  PINBALL (FIX MEM DISP) PREVENTS DCA HERE
047893,000081:    4731           56135                           XCH      MPTEMP                                #  SAVE 1ST WD, FETCH OLD FBANK AND SBANK.
047894,000082:    4732           00006                           EXTEND                                         
047895,000083:    4733           01007                           WRITE    SUPERBNK                              #  RESTORE SUPERBANK.
047896,000084:    4734           00003                           RELINT                                         
047897,000085:    4735           54004                           TS       FBANK                                 #  RESTORE FBANK.
047898,000086:    4736           30135                           CA       MPTEMP                                #  RECOVER FIRST WORD OF DATA.
047899,000087:    4737           00002                           RETURN                                         #  24 WDS. DATACALL 516 MU, SUPDACAL 432 MU
047900,000088: 

Page 1105

047902,000090:                                                                                                  #  THE FOLLOWING ROUTINES ARE IDENTICAL TO BANKCALL AND SWCALL EXCEPT THAT THEY ARE USED IN INTERRUPT.
047903,000091: 
047904,000092:    4740           52073        IBNKCALL           DXCH     RUPTREG3                              #  USES RUPTREG3,4 FOR DP RETURN ADDRESS.
047905,000093:    4741           50002                           INDEX    Q                                     
047906,000094:    4742           30000                           CAF      0                                     
047907,000095:    4743           24002                           INCR     Q                                     
047908,000096: 
047909,000097:    4744           54001        ISWCALL            TS       L                                     
047910,000098:    4745           22004                           LXCH     FBANK                                 
047911,000099:    4746           75054                           MASK     LOW10                                 
047912,000100:    4747           56002                           XCH      Q                                     
047913,000101:    4750           52073                           DXCH     RUPTREG3                              
047914,000102:    4751           50002                           INDEX    Q                                     
047915,000103:    4752           02000                           TC       10000                                 
047916,000104: 
047917,000105:    4753           56073        ISWRETRN           XCH      RUPTREG4                              
047918,000106:    4754           56004                           XCH      FBANK                                 
047919,000107:    4755           56073                           XCH      RUPTREG4                              
047920,000108:    4756           00072                           TC       RUPTREG3                              
047921,000109: 
047922,000110:                                                                                                  #  2. USPRCADR ACCESSES INTERPRETIVE CODING IN OTHER THAN THE USER'S FBANK.  THE CALLING SEQUENCE IS AS FOLLOWS:
047923,000111:                                                                                                  #        L       TC      USPRCADR
047924,000112:                                                                                                  #        L+1     CADR    INTPRETX        INTPRETX IS THE INTERPRETIVE CODING
047925,000113:                                                                                                  #                                        RETURN IS TO L+2
047926,000114: 
047927,000115:    4757           54164        USPRCADR           TS       LOC                                   #  SAVE A
047928,000116:    4760           35010                           CA       BIT8                                  
047929,000117:    4761           54023                           TS       EDOP                                  #  EXIT INSTRUCTION TO EDOP
047930,000118:    4762           30006                           CA       BBANK                                 
047931,000119:    4763           54165                           TS       BANKSET                               #  USER'S BBANK TO BANKSET
047932,000120:    4764           50002                           INDEX    Q                                     
047933,000121:    4765           30000                           CA       0                                     
047934,000122:    4766           54004                           TS       FBANK                                 #  INTERPRETIVE BANK TO FBANK
047935,000123:    4767           75054                           MASK     LOW10                                 #  YIELDS INTERPRETIVE RELATIVE ADDRESS
047936,000124:    4770           56002                           XCH      Q                                     #  INTERPRETIVE ADDRESS TO Q, FETCHING L+1
047937,000125:    4771           56164                           XCH      LOC                                   #  L+1 TO LOC, RETRIEVING ORIGINAL A
047938,000126:    4772           14707                           TCF      Q+10000                               
047939,000127: 

Page 1106

047941,000129:                                                                                                  #  THERE ARE FOUR POSSIBLE SETTINGS FOR CHANNEL 07.  (CHANNEL 07 CONTAINS THE SUPERBANK SETTING.)
047942,000130: 
047943,000131:                                                                                                  #                                        PSEUDO-FIXED     OCTAL PSEUDO
047944,000132:                                                                                                  #  SUPERBANK     SETTING S-REG. VALUE    BANK NUMBERS     ADDRESSES
047945,000133:                                                                                                  #  ----------    ------- ------------     ------------     ------------
047946,000134:                                                                                                  #  SUPERBANK 3     0XX    2000 - 3777       30 - 37       70000 - 107777         (WHERE XX CAN BE ANYTHING AND
047947,000135:                                                                                                  #                                                                                WILL USUALLY BE SEEN AS 11)
047948,000136:                                                                                                  #  SUPERBANK 4     100    2000 - 3777       40 - 47      110000 - 127777         (AS FAR AS IT CAN BE SEEN,
047949,000137:                                                                                                  #                                                                                ONLY BANKS 40-43 WILL EVER BE
047950,000138:                                                                                                  #                                                                                AND ARE PRESENTLY AVAILABLE)
047951,000139:                                                                                                  #  SUPERBANK 5     101    2000 - 3777       50 - 57      130000 - 147777         (PRESENTLY NOT AVAILABLE TO
047952,000140:                                                                                                  #                                                                                THE USER)
047953,000141:                                                                                                  #  SUPERBANK 6     110    2000 - 3777       60 - 67      150000 - 167777         (PRESENTLY NOT AVAILABLE TO
047954,000142:                                                                                                  #                                                                                THE USER)
047955,000143:                                                                                                  #  *** THIS ROUTINE MAY BE CALLED BY ANY PROGRAM LOCATED IN BANKS 00 - 27.  I.E., NO PROGRAM LIVING IN ANY
047956,000144:                                                                                                  #  SUPERBANK SHOULD USE SUPERSW. ***
047957,000145: 
047958,000146:                                                                                                  #  SUPERSW MAY BE CALLED IN THIS FASHION:
047959,000147:                                                                                                  #        CAF     ABBCON          WHERE -- ABBCON  BBCON  SOMETHIN --
047960,000148:                                                                                                  #        TCR     SUPERSW         (THE SUPERBNK BITS ARE IN THE BBCON)
047961,000149:                                                                                                  #        ...       ...
047962,000150:                                                                                                  #         .         .
047963,000151:                                                                                                  #         .         .
047964,000152:                                                                                                  #  OR IN THIS FASHION:
047965,000153:                                                                                                  #        CAF     SUPERSET        WHERE SUPERSET IS ONE OF THE FOUR AVAILABLE
047966,000154:                                                                                                  #        TCR     SUPERSW         SUPERBANK BIT CONSTANTS:
047967,000155:                                                                                                  #        ...       ...                   SUPER011 OCTAL  60
047968,000156:                                                                                                  #         .         .                    SUPER100 OCTAL 100
047969,000157:                                                                                                  #         .         .                    SUPER101 OCTAL 120
047970,000158:                                                                                                  #                                        SUPER110 OCTAL 140
047971,000159: 
047972,000160:    4773           00006        SUPERSW            EXTEND                                         
047973,000161:    4774           01007                           WRITE    SUPERBNK                              #  WRITE BITS 7-6-5 OF THE ACCUMULATOR INTO
047974,000162:                                                                                                  #  CHANNEL 07
047975,000163:    4775           00002                           TC       Q                                     #  TC TO INSTRUCTION FOLLOWING
047976,000164:                                                                                                  #        TC SUPERSW
047977,000165: 
047978,000166: 
047979,000167: 

End of include-file INTER-BANK_COMMUNICATION.agc.  Parent file is MAIN.agc