Source Code

These source-code files are part of a reconstructed copy of Comanche 44, the initial release (though not the final mission release) of the Apollo 10 Command Module (CM) Apollo Guidance Computer (AGC) software. Subsequent releases were Comanche 45 and Comanche 45/2 (the flown release on Apollo 10). The reconstruction is believed to be exactly accurate, but in the absence of an actual Apollo-era listing of Comanche 44, some explanation of the reconstruction process is needed to insure confidence in that accuracy.

The starting point was the source code of Comanche 51 (separately previously reconstructed from an Apollo-era listing of Comanche 55, flown on Apollo 11). Comanche 51 source code was then modified by undoing changes known to have been made between revisions 44 and 51. The now-reconstructed Comanche 44 source code was verified by assembling it and checking that the assembled code had the expected known-correct memory-bank checksums. Note that page numbers in the reconstructed code match those on the Comanche 55 printout, although the source code would likely have different page numbers in a contemporary Comanche 44 listing.

Annotations that were not present in the contemporary source code have been added to the reconstructed code to justify each change relative to Comanche 51. Here's a guide to the Apollo documentation referenced in those annotations:
In most cases, only the titles (rather than the full texts) of PCRs are known. In addition to the explanatory annotations, there is also a step-by-step commentary about the reconstruction process.

Comments expected to have been present in 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.

051597,000002:                                                                                                  ## Copyright:   Public domain.
051598,000003:                                                                                                  ## Filename:    FIXED-FIXED_CONSTANT_POOL.agc
051599,000004:                                                                                                  ## Purpose:     A section of Comanche revision 044.
051600,000005:                                                                                                  ##              It is part of the reconstructed source code for the
051601,000006:                                                                                                  ##              original release of the flight software for the Command
051602,000007:                                                                                                  ##              Module's (CM) Apollo Guidance Computer (AGC) for Apollo 10.
051603,000008:                                                                                                  ##              The code has been recreated from a copy of Comanche 055. It
051604,000009:                                                                                                  ##              has been adapted such that the resulting bugger words
051605,000010:                                                                                                  ##              exactly match those specified for Comanche 44 in NASA drawing
051606,000011:                                                                                                  ##              2021153D, which gives relatively high confidence that the
051607,000012:                                                                                                  ##              reconstruction is correct.
051608,000013:                                                                                                  ## Assembler:   yaYUL
051609,000014:                                                                                                  ## Contact:     Ron Burkey <info@sandroid.org>.
051610,000015:                                                                                                  ## Website:     www.ibiblio.org/apollo/index.html
051611,000016:                                                                                                  ## Mod history: 2020-12-03 MAS  Created from Comanche 51.
051612,000017: 

Page 1200

051614,000019:    4776                                           BLOCK    02                                    
051615,000020:    4776                                           COUNT    02/FCONS                              
051616,000021: 
051617,000022:                                                                                                  #  THE FOLLOWING TABLE OF 18 VALUES IS INDEXED.  DO NOT INSERT OR REMOVE ANY QUANTITIES.
051618,000023: 
051619,000024:    4776           37777        DPOSMAX            OCT      37777                                 #  MUST PRECEDE POSMAX
051620,000025:    4777           37777        POSMAX             OCT      37777                                 
051621,000026: 
051622,000027:    5000     5000               LIMITS             =        NEG1/2                                
051623,000028: 
051624,000029:    5000           57777        NEG1/2             OCT      -20000                                #  USED BY SIN ROUTINE (MUST BE TWO 
051625,000030:                                                                                                  #  LOCATIONS IN FRONT OF BIT14)
051626,000031: 
051627,000032:                                                                                                  #  BIT TABLE                                     
051628,000033: 
051629,000034:    5001           40000        BIT15              OCT      40000                                 
051630,000035:    5002           20000        BIT14              OCT      20000                                 
051631,000036:    5003           10000        BIT13              OCT      10000                                 
051632,000037:    5004           04000        BIT12              OCT      04000                                 
051633,000038:    5005           02000        BIT11              OCT      02000                                 
051634,000039:    5006           01000        BIT10              OCT      01000                                 
051635,000040:    5007           00400        BIT9               OCT      00400                                 
051636,000041:    5010           00200        BIT8               OCT      00200                                 
051637,000042:    5011           00100        BIT7               OCT      00100                                 
051638,000043:    5012           00040        BIT6               OCT      00040                                 
051639,000044:    5013           00020        BIT5               OCT      00020                                 
051640,000045:    5014           00010        BIT4               OCT      00010                                 
051641,000046:    5015           00004        BIT3               OCT      00004                                 
051642,000047:    5016           00002        BIT2               OCT      00002                                 
051643,000048:    5017           00001        BIT1               OCT      00001                                 
051644,000049: 
051645,000050:                                                                                                  #  DO NOT DESTROY THIS COMBINATION, SINCE IT IS USED IN DOUBLE PRECISION INSTRUCTIONS.
051646,000051:    5020           77777        NEG0               OCT      -0                                    #  MUST PRECEDE ZERO
051647,000052:    5021           00000        ZERO               OCT      0                                     #  MUST FOLLOW NEG0
051648,000053:                                                                                                  #  BIT1          OCT     00001
051649,000054:                                                                                                  #  NO.WDS        OCT     2               INTERPRETER
051650,000055:                                                                                                  #  OCTAL3        OCT     3               INTERPRETER
051651,000056:                                                                                                  #  R3D1          OCT     4               PINBALL
051652,000057:    5022           00005        FIVE               OCT      5                                     
051653,000058:                                                                                                  #  REVCNT        OCT     6               INTERPRETER
051654,000059:    5023           00007        SEVEN              OCT      7                                     
051655,000060:                                                                                                  #  BIT4          OCT     00010
051656,000061:                                                                                                  #  R2D1          OCT     11              PINBALL
051657,000062:    5024     4334               OCT11              =        R2D1                                  #  P20S
051658,000063:                                                                                                  #  BINCON        DEC     10              PINBALL         (OCTAL 12)
051659,000064:    5024           00013        ELEVEN             DEC      11         B-14                       
051660,000065:                                                                                                  #  OCT14         OCT     14              ALARM AND ABORT (FILLER)
051661,000066:    5025           00015        OCT15              OCT      15                                    
051662,000067:                                                                                                  #  R1D1          OCT     16              PINBALL

Page 1201

051664,000069:    5026           00017        LOW4               OCT      17                                    
051665,000070:                                                                                                  #  BIT5          OCT     00020
051666,000071:                                                                                                  #  ND1           OCT     21              PINBALL
051667,000072:                                                                                                  #  VD1           OCT     23              PINBALL
051668,000073:                                                                                                  #  OCT24         OCT     24              SERVICE ROUTINES
051669,000074:                                                                                                  #  MD1           OCT     25              PINBALL
051670,000075:    5027           00030        BITS4&5            OCT      30                                    
051671,000076:                                                                                                  #  OCT31         OCT     31              SERVICE ROUTINES
051672,000077:    5030           00032        CALLCODE           OCT      00032                                 
051673,000078:                                                                                                  #  LOW5          OCT     37              PINBALL
051674,000079:                                                                                                  #  33DEC         DEC     33              PINBALL         (OCTAL 41)
051675,000080:                                                                                                  #  34DEC         DEC     34              PINBALL         (OCTAL 42)
051676,000081:    5031           00045        TBUILDFX           DEC      37         B-14                       #  BUILDUP FOR CONVIENCE IN DAPTESTING
051677,000082:    5032           00046        TDECAYFX           DEC      38         B-14                       #  CONVENIENCE FOR DAPTESTING
051678,000083:                                                                                                  #  BIT6          OCT     00040
051679,000084:    5033           00050        OCT50              OCT      50                                    
051680,000085:    5034           00055        DEC45              DEC      45         B-14                       
051681,000086:    5035           00060        SUPER011           OCT      60                                    #  BITS FOR SUPERBNK SETTING 011.
051682,000087:    5036           00062        .5SEC              DEC      50         B-14                       
051683,000088:                                                                                                  #  BIT7          OCT     00100
051684,000089: 
051685,000090:    5037     5011               SUPER100           =        BIT7                                  #  BITS FOR SUPERBNK SETTING 100
051686,000091:                                                                                                  #  (LAST 4K OF ROPE)
051687,000092:    5037           00120        SUPER101           OCT      120                                   #  BITS FOR SUPERBNK SETTING 101
051688,000093:                                                                                                  #  OCT121        OCT     121             SERVICE ROUTINES
051689,000094:                                                                                                  #  (FIRST 8K OF ACM)
051690,000095:    5040           00140        SUPER110           OCT      140                                   #  BITS FOR SUPERBNK SETTING 110.
051691,000096:                                                                                                  #  (LAST 8K OF ACM)
051692,000097:    5041           00144        1SEC               DEC      100        B-14                       
051693,000098:                                                                                                  #  LOW7          OCT     177             INTERPRETER
051694,000099:                                                                                                  #  BIT8          OCT     00200
051695,000100:                                                                                                  #  OT215         OCT     215             ALARM AND ABORT
051696,000101:                                                                                                  #  8,5           OCT     00220           P20-P25 SUNDANCE
051697,000102:    5042           00310        2SECS              DEC      200        B-14                       
051698,000103:                                                                                                  #  LOW8          OCT     377             PINBALL
051699,000104:                                                                                                  #  BIT9          OCT     00400
051700,000105:    5043           00401        GN/CCODE           OCT      00401                                 #  SET S/C CONTROL SWITCH TO G/N
051701,000106:    5044           00454        3SECS              DEC      300        B-14                       
051702,000107:    5045           00620        4SECS              DEC      400        B-14                       
051703,000108:    5046           00777        LOW9               OCT      777                                   
051704,000109:                                                                                                  #  BIT10         OCT     01000
051705,000110:                                                                                                  #  5.5DEGS       DEC     .03056          P20-P25 SUNDANCE        (OCTAL 00765)
051706,000111:                                                                                                  #  OCT1103       OCT     1103            ALARM AND ABORT
051707,000112:    5047           01124        C5/2               DEC      .0363551                              #                        (OCTAL 01124)
051708,000113:    5050           01211        V05N09             VN       0509                                  #  (SAME AS OCTAL 1211)
051709,000114:    5051           01400        OCT1400            OCT      01400                                 
051710,000115:    5052           01426        V06N22             VN       0622                                  
051711,000116:                                                                                                  #  MID5          OCT     1740            PINBALL
051712,000117:    5053           01776        BITS2-10           OCT      1776                                  
051713,000118:    5054           01777        LOW10              OCT      1777                                  

Page 1202

051715,000120:                                                                                                  #  BIT11         OCT     02000
051716,000121:                                                                                                  #  2K+3          OCT     2003            PINBALL
051717,000122:    5055           02177        LOW7+2K            OCT      2177                                  #  OP CODE MASK + BANK 1 FBANK SETTING.
051718,000123:    5056           02400        EBANK5             OCT      02400                                 
051719,000124:    5057           03000        PRIO3              OCT      03000                                 
051720,000125:    5060           03400        EBANK7             OCT      03400                                 
051721,000126:                                                                                                  #  LOW11         OCT     3777            PINBALL
051722,000127:                                                                                                  #  BIT12         OCT     04000
051723,000128:                                                                                                  #  RELTAB        OCT     04025           T4RUPT
051724,000129:    5061           05000        PRIO5              OCT      05000                                 
051725,000130:    5062           06000        PRIO6              OCT      06000                                 
051726,000131:    5063           07000        PRIO7              OCT      07000                                 
051727,000132: 
051728,000133:                                                                                                  #  BIT13         OCT     10000
051729,000134:                                                                                                  #                OCT     10003           T4RUPT  RELTAB +1D
051730,000135:                                                                                                  #  13,7,2        OCT     10102           P20-P25 SUNDANCE
051731,000136:    5064           11000        PRIO11             OCT      11000                                 
051732,000137:                                                                                                  #  PRIO12        OCT     12000           BANKCALL
051733,000138:    5065           13000        PRIO13             OCT      13000                                 
051734,000139:    5066           14000        PRIO14             OCT      14000                                 
051735,000140:                                                                                                  #                OCT     14031           T4RUPT  RELTAB +2D
051736,000141:    5067           15000        PRIO15             OCT      15000                                 
051737,000142:    5070           16000        PRIO16             OCT      16000                                 
051738,000143:                                                                                                  #  85DEGS        DEC     .45556          P20-P25 SUNDANCE        (OCTAL 16450)
051739,000144:    5071           17000        PRIO17             OCT      17000                                 
051740,000145:    5072           17770        OCT17770           OCT      17770                                 
051741,000146:                                                                                                  #  BIT14         OCT     20000
051742,000147:                                                                                                  #                OCT     20033           T4RUPT  RELTAB +3D
051743,000148:    5073           21000        PRIO21             OCT      21000                                 
051744,000149:    7657                                           BLOCK    03                                    
051745,000150:    7657                                           COUNT    03/FCONS                              
051746,000151: 
051747,000152:    7657           22000        PRIO22             OCT      22000                                 #  SERVICE ROUTINES
051748,000153:    7660           23000        PRIO23             OCT      23000                                 
051749,000154:    7661           24000        PRIO24             OCT      24000                                 
051750,000155:                                                                                                  #  5/8+1         OCT     24001           SINGLE PRECISION SUBROUTINES
051751,000156:                                                                                                  #                OCT     24017           T4RUPT  RELTAB +4D
051752,000157:    7662           25000        PRIO25             OCT      25000                                 
051753,000158:    7663           26000        PRIO26             OCT      26000                                 
051754,000159:    7664           27000        PRIO27             OCT      27000                                 
051755,000160:                                                                                                  #  CHRPRIO       OCT     30000           PINBALL
051756,000161:                                                                                                  #                OCT     30036           T4RUPT  RELTAB +5D
051757,000162:    7665           31000        PRIO31             OCT      31000                                 
051758,000163:    7666           31103        C1/2               DEC      .7853134                              #                        (OCTAL 31103)
051759,000164:    7667           32000        PRIO32             OCT      32000                                 
051760,000165:    7670           33000        PRIO33             OCT      33000                                 
051761,000166:    7671           34000        PRIO34             OCT      34000                                 
051762,000167:                                                                                                  #                OCT     34034           T4RUPT  RELTAB +6D              
051763,000168:    7672           35000        PRIO35             OCT      35000                                 
051764,000169:    7673           36000        PRIO36             OCT      36000                                 

Page 1203

051766,000171:    7674           37000        PRIO37             OCT      37000                                 
051767,000172:    7675           37401        63/64+1            OCT      37401                                 
051768,000173:                                                                                                  #  MID7          OCT     37600           PINBALL
051769,000174:    7676           37766        OCT37766           OCT      37766                                 
051770,000175:    7677           37774        OCT37774           OCT      37774                                 
051771,000176:    7700           37776        OCT37776           OCT      37776                                 
051772,000177:                                                                                                  #  DPOSMAX       OCT     37777
051773,000178:                                                                                                  #  BIT15         OCT     40000
051774,000179:                                                                                                  #  OCT40001      OCT     40001           INTERPRETER (CS 1 INSTRUCTION)
051775,000180:    7701           40014        DLOADCOD           OCT      40014                                 
051776,000181:    7702           40015        DLOAD*             OCT      40015                                 
051777,000182:                                                                                                  #                OCT     40023           T4RUPT  RELTAB +7D
051778,000183:    7703           40040        BIT15+6            OCT      40040                                 
051779,000184:    7704           40200        OCT40200           OCT      40200                                 
051780,000185:                                                                                                  #                OCT     44035           T4RUPT  RELTAB +8D
051781,000186:                                                                                                  #                OCT     50037           T4RUPT  RELTAB +9D
051782,000187:                                                                                                  #                OCT     54000           T4RUPT  RELTAB +10D
051783,000188:    7705           57777        -BIT14             OCT      57777                                 
051784,000189:                                                                                                  #  RELTAB11      OCT     60000           T4RUPT
051785,000190:    7706           65552        C3/2               DEC      -.3216147                             #                        (OCTAL 65552)
051786,000191:    7707           70000        13,14,15           OCT      70000                                 
051787,000192:    7710           73777        -1/8               OCT      73777                                 
051788,000193:    7711           74000        HIGH4              OCT      74000                                 
051789,000194:    7712           74056        -ENDERAS           DEC      -2001      B-14                       #                        (OCTAL 74056)
051790,000195:                                                                                                  #  HI5           OCT     76000           PINBALL
051791,000196:    7713           77700        HIGH9              OCT      77700                                 
051792,000197:                                                                                                  #  -ENDVAC       DEC     -45             INTERPRETER             (OCTAL 77722)
051793,000198:                                                                                                  #  -OCT10        OCT     -10                                      (OCT 77767)
051794,000199:                                                                                                  #  NEG4          DEC     -4                                      (OCTAL 77773)
051795,000200:    7714           77774        NEG3               DEC      -3         B-14                       
051796,000201:    7715           77775        NEG2               OCT      77775                                 
051797,000202:    7716           77776        NEGONE             DEC      -1         B-14                       
051798,000203: 

Page 1204

051800,000205: 
051801,000206:                                                                                                  #  DEFINED BY EQUALS
051802,000207: 
051803,000208:                                                                                                  #  IT WOULD BE TO THE USERS ADVANTAGE TO OCCASIONALLY CHECK ANY OF THESE SYMBOLS IN ORDER TO PREVENT ANY
051804,000209:                                                                                                  #  ACCIDENTAL DEFINITION CHANGES.
051805,000210: 
051806,000211:    7717     7716               MINUS1             =        NEG1                                  
051807,000212:    7717     7716               NEG1               =        NEGONE                                
051808,000213:    7717     5017               ONE                =        BIT1                                  
051809,000214:    7717     5016               TWO                =        BIT2                                  
051810,000215:    7717     6214               THREE              =        OCTAL3                                
051811,000216:    7717     6214               LOW2               =        THREE                                 
051812,000217:    7717     5015               FOUR               =        BIT3                                  
051813,000218:    7717     6211               SIX                =        REVCNT                                
051814,000219:    7717     5023               LOW3               =        SEVEN                                 
051815,000220:    7717     5014               EIGHT              =        BIT4                                  
051816,000221:    7717     4334               NINE               =        R2D1                                  
051817,000222:    7717     4377               TEN                =        BINCON                                
051818,000223:    7717     5024               NOUTCON            =        ELEVEN                                
051819,000224:    7717     4374               OCT23              =        VD1                                   
051820,000225:    7717     4376               OCT25              =        MD1                                   
051821,000226:    7717     5006               PRIO1              =        BIT10                                 
051822,000227:    7717     5051               EBANK3             =        OCT1400                               
051823,000228:    7717     5005               PRIO2              =        BIT11                                 
051824,000229:    7717     5037               OCT120             =        SUPER101                              
051825,000230:    7717     5040               OCT140             =        SUPER110                              
051826,000231:    7717     5005               2K                 =        BIT11                                 
051827,000232:    7717     5005               EBANK4             =        BIT11                                 
051828,000233:    7717     5004               PRIO4              =        BIT12                                 
051829,000234:    7717     5057               EBANK6             =        PRIO3                                 
051830,000235:    7717     5003               QUARTER            =        BIT13                                 
051831,000236:    7717     5003               PRIO10             =        BIT13                                 
051832,000237:    7717     7632               OCT10001           =        CCSL                                  
051833,000238:    7717     5002               POS1/2             =        HALF                                  
051834,000239:    7717     5002               PRIO20             =        BIT14                                 
051835,000240:    7717     5002               HALF               =        BIT14                                 
051836,000241:    7717     4371               PRIO30             =        CHRPRIO                               
051837,000242:    7717     4371               BIT13-14           =        PRIO30                                #  INTERPRETER USES IN PROCESSING STORECODE
051838,000243:    7717     6440               OCT30002           =        TLOAD      +1                         
051839,000244:    7717     7671               B12T14             =        PRIO34                                
051840,000245:    7717     5001               NEGMAX             =        BIT15                                 
051841,000246:    7717     5001               VLOADCOD           =        BIT15                                 
051842,000247:    7717     6056               VLOAD*             =        OCT40001                              
051843,000248:    7717     4105               OCT60000           =        RELTAB11                              
051844,000249:    7717     4364               BANKMASK           =        HI5                                   
051845,000250: 

End of include-file FIXED-FIXED_CONSTANT_POOL.agc.  Parent file is MAIN.agc