Source Code

These source-code files derive from a printout of Luminary 116 (the Apollo 12 Lunar Module guidance computer program), from the personal library of original AGC developer Don Eyles, digitally photographed at archive.org, financially sponsored by Ron Burkey, and transcribed to source code by a team of volunteers. This colorized, syntax-highlighted form was created by assembling that transcribed source code. Note that the full page images are available on the Virtual AGC project page at archive.org, while reduced-size images are presented at the VirtualAGC project website. Report or fix any transcription errors at the Virtual AGC project code repository.

Notations on the program listing read, in part:

	GAP:  ASSEMBLE REVISION 116 OF AGC PROGRAM LUMINARY BY NASA 2021112-071
	19:09 AUG. 11,1969
Note that the date is the date of the printout, not the date of the program revision.

029862,000002:                                                                                                  ## Copyright:   Public domain.
029863,000003:                                                                                                  ## Filename:    R31.agc
029864,000004:                                                                                                  ## Purpose:     A section of Luminary revision 116.
029865,000005:                                                                                                  ##              It is part of the source code for the Lunar Module's (LM) 
029866,000006:                                                                                                  ##              Apollo Guidance Computer (AGC) for Apollo 12.
029867,000007:                                                                                                  ##              This file is intended to be a faithful transcription, except
029868,000008:                                                                                                  ##              that the code format has been changed to conform to the
029869,000009:                                                                                                  ##              requirements of the yaYUL assembler rather than the
029870,000010:                                                                                                  ##              original YUL assembler.
029871,000011:                                                                                                  ## Reference:   pp. 703-708
029872,000012:                                                                                                  ## Assembler:   yaYUL
029873,000013:                                                                                                  ## Contact:     Ron Burkey <info@sandroid.org>.
029874,000014:                                                                                                  ## Website:     www.ibiblio.org/apollo/index.html
029875,000015:                                                                                                  ## Mod history: 2017-01-22 MAS  Created from Luminary 99.
029876,000016:                                                                                                  ##              2017-03-09 RSB  Transcribed, and then proofed comment-text using
029877,000017:                                                                                                  ##                              3-way diff vs Luminary 99 and Luminary 131.
029878,000018:                                                                                                  ##                              (Admittedly, the former is more for detecting errors
029879,000019:                                                                                                  ##                              in Luminary 99 than the other way around.)
029880,000020: 

Page 703

029882,000022: 40,3737                                           BANK     40                                    
029883,000023: 40,2000                                           SETLOC   R31LOC                                
029884,000024: 40,2000                                           BANK                                           
029885,000025: 
029886,000026: 40,3737                                           COUNT*   $$/R31                                
029887,000027: 
029888,000028: 40,3737           35015        R31CALL            CAF      PRIO3                                 
029889,000029: 40,3740           05105                           TC       FINDVAC                               
029890,000030: 40,3741  E7,1470                                  EBANK=   SUBEXIT                               
029891,000031: 40,3741           03121 76067                     2CADR    V83CALL                               
029892,000032: 
029893,000033: 40,3743           05221        DSPDELAY           TC       FIXDELAY                              
029894,000034: 40,3744           00144                           DEC      100        B-14                       
029895,000035: 40,3745           31043                           CA       EXTVBACT                              
029896,000036: 40,3746           74740                           MASK     BIT12                                 
029897,000037: 40,3747           00006                           EXTEND                                         
029898,000038: 40,3750           13743                           BZF      DSPDELAY                              
029899,000039: 
029900,000040: 40,3751           35017                           CAF      PRIO5                                 
029901,000041: 40,3752           05072                           TC       NOVAC                                 
029902,000042: 40,3753  E7,1611                                  EBANK=   TSTRT                                 
029903,000043: 40,3753           03113 76067                     2CADR    DISPN5X                               
029904,000044: 
029905,000045: 40,3755           15261                           TCF      TASKOVER                              
029906,000046: 
029907,000047: 37,3113                                           BANK     37                                    
029908,000048: 37,2000                                           SETLOC   R31                                   
029909,000049: 37,2000                                           BANK                                           
029910,000050: 37,3113                                           COUNT*   $$/R31                                
029911,000051: 
029912,000052: 37,3113           33407        DISPN5X            CAF      V16N54                                
029913,000053: 37,3114           04616                           TC       BANKCALL                              
029914,000054: 37,3115           20334                           CADR     GOMARKF                               
029915,000055: 37,3116           05563                           TC       B5OFF                                 
029916,000056: 37,3117           05563                           TC       B5OFF                                 
029917,000057: 37,3120           13113                           TCF      DISPN5X                               
029918,000058: 
029919,000059: 37,3121           40103        V83CALL            CS       FLAGWRD7                              #  TEST AVERAGE G FLAG
029920,000060: 37,3122           74747                           MASK     AVEGFBIT                              
029921,000061: 37,3123           00006                           EXTEND                                         
029922,000062: 37,3124           13377                           BZF      MUNG?                                 #  ON - TEST MUNFLAG
029923,000063: 
029924,000064: 37,3125           40104                           CS       FLAGWRD8                              
029925,000065: 37,3126           74744                           MASK     SURFFBIT                              
029926,000066: 37,3127           00006                           EXTEND                                         
029927,000067: 37,3130           13403                           BZF      ONEBASE                               #  ON SURFACE - BYPASS LEMPREC
029928,000068: 
029929,000069: 37,3131           06042                           TC       INTPRET                               #  EXTRAPOLATE BOTH STATE VECTORS
029930,000070: 37,3132           77634                           RTB                                            

Page 704

029932,000072: 37,3133           21574                                    LOADTIME                              
029933,000073: 37,3134           34041                           STCALL   TDEC1                                 
029934,000074: 37,3135           27060                                    LEMPREC                               #  PRECISION BASE VECTOR FOR LM
029935,000075: 37,3136           77775                           VLOAD                                          
029936,000076: 37,3137           00017                                    RATT1                                 
029937,000077: 37,3140           26170                           STOVL    BASETHP                               
029938,000078: 37,3141           00025                                    VATT1                                 
029939,000079: 37,3142           16105                           STODL    BASETHV                               
029940,000080: 37,3143           00015                                    TAT                                   
029941,000081: 37,3144           02114        DOCMBASE           STORE    BASETIME                              #  PRECISION BASE VECTOR FOR CM
029942,000082: 37,3145           34041                           STCALL   TDEC1                                 
029943,000083: 37,3146           27044                                    CSMPREC                               
029944,000084: 37,3147           77775                           VLOAD                                          
029945,000085: 37,3150           00017                                    RATT1                                 
029946,000086: 37,3151           26140                           STOVL    BASEOTP                               
029947,000087: 37,3152           00025                                    VATT1                                 
029948,000088: 37,3153           02120                           STORE    BASEOTV                               
029949,000089: 37,3154           77776                           EXIT                                           
029950,000090: 
029951,000091: 37,3155           40103        REV83              CS       FLAGWRD7                              
029952,000092: 37,3156           74747                           MASK     AVEGFBIT                              
029953,000093: 37,3157           00006                           EXTEND                                         
029954,000094: 37,3160           13326                           BZF      GETRVN                                #  IF AVEGFLAG SET, USE RN,VN
029955,000095: 
029956,000096: 37,3161           40104                           CS       FLAGWRD8                              
029957,000097: 37,3162           74744                           MASK     SURFFBIT                              
029958,000098: 37,3163           00006                           EXTEND                                         
029959,000099: 37,3164           13370                           BZF      R31SURF                               #  IF ON SURFACE, USE LEMAREC
029960,000100: 
029961,000101: 37,3165           06042                           TC       INTPRET                               #  DO CONIC EXTRAPOLATION FOR BOTH VEHICLES
029962,000102: 37,3166           77634                           RTB                                            
029963,000103: 37,3167           21574                                    LOADTIME                              
029964,000104: 37,3170           34041                           STCALL   TDEC1                                 
029965,000105: 37,3171           27412                                    INTSTALL                              
029966,000106: 37,3172           43175                           VLOAD    CLEAR                                 
029967,000107: 37,3173           02170                                    BASETHP                               
029968,000108: 37,3174           00263                                    MOONFLAG                              
029969,000109: 37,3175           25535                           STOVL    RCV                                   
029970,000110: 37,3176           02105                                    BASETHV                               
029971,000111: 37,3177           15543                           STODL    VCV                                   
029972,000112: 37,3200           02114                                    BASETIME                              
029973,000113: 37,3201           43014                           BOF      SET                                   #  GET APPROPRIATE MOONFLAG SETTING
029974,000114: 37,3202           04344                                    MOONTHIS                              
029975,000115: 37,3203           77205                                    +2                                    
029976,000116: 37,3204           00063                                    MOONFLAG                              
029977,000117: 37,3205           77614                           SET                                            
029978,000118: 37,3206           01473                                    INTYPFLG                              #  CONIC EXTRAP.
029979,000119: 37,3207           35517                           STCALL   TET                                   
029980,000120: 37,3210           27110                                    INTEGRVS                              #  INTEGRATION --- AT LAST ---
029981,000121: 37,3211           77775        OTHCONIC           VLOAD                                          

Page 705

029983,000123: 37,3212           00001                                    RATT                                  
029984,000124: 37,3213           26207                           STOVL    RONE                                  
029985,000125: 37,3214           00007                                    VATT                                  
029986,000126: 37,3215           36215                           STCALL   VONE                                  #  GET SET FOR CONIC EXTRAP., OTHER.
029987,000127: 37,3216           27412                                    INTSTALL                              
029988,000128: 37,3217           71214                           SET      DLOAD                                 
029989,000129: 37,3220           01473                                    INTYPFLG                              
029990,000130: 37,3221           00015                                    TAT                                   
029991,000131: 37,3222           00041        OTHINT             STORE    TDEC1                                 
029992,000132: 37,3223           43175                           VLOAD    CLEAR                                 
029993,000133: 37,3224           02140                                    BASEOTP                               
029994,000134: 37,3225           00263                                    MOONFLAG                              
029995,000135: 37,3226           25535                           STOVL    RCV                                   
029996,000136: 37,3227           02120                                    BASEOTV                               
029997,000137: 37,3230           15543                           STODL    VCV                                   
029998,000138: 37,3231           02114                                    BASETIME                              
029999,000139: 37,3232           43014                           BOF      SET                                   
030000,000140: 37,3233           04344                                    MOONTHIS                              
030001,000141: 37,3234           77236                                    +2                                    
030002,000142: 37,3235           00063                                    MOONFLAG                              
030003,000143: 37,3236           35517                           STCALL   TET                                   
030004,000144: 37,3237           27110                                    INTEGRVS                              
030005,000145: 37,3240           52375        COMPDISP           VLOAD    VSU                                   
030006,000146: 37,3241           00001                                    RATT                                  
030007,000147: 37,3242           02207                                    RONE                                  
030008,000148: 37,3243           65234                           RTB      PDDL                                  
030009,000149: 37,3244           21725                                    NORMUNX1                              #  UNIT(RANGE) TO PD 0-5
030010,000150: 37,3245           00045                                    36D                                   
030011,000151: 37,3246           77657                           SL*                                            #  RESCALE AFTER NORMUNIT
030012,000152: 37,3247           20201                                    0,1                                   
030013,000153: 37,3250           26201                           STOVL    RANGE                                 #  SCALED 2(29)M
030014,000154: 37,3251           00007                                    VATT                                  
030015,000155: 37,3252           50251                           VSU      DOT                                   #  (VCM-VLM).UNIT(LOS), PD=0
030016,000156: 37,3253           02215                                    VONE                                  
030017,000157: 37,3254           77752                           SL1                                            #  SCALED 2(7)M/CS
030018,000158: 37,3255           26203                           STOVL    RRATE                                 
030019,000159: 37,3256           02207                                    RONE                                  
030020,000160: 37,3257           63256                           UNIT     PDVL                                  #  UNIT(R) TO PD 0-5
030021,000161: 37,3260           06516                                    UNITZ                                 
030022,000162: 37,3261           77624                           CALL                                           
030023,000163: 37,3262           47663                                    CDU*NBSM                              
030024,000164: 37,3263           41505                           VXM      PUSH                                  #  UNIT(Z)/4 TO PD 6-11
030025,000165: 37,3264           01734                                    REFSMMAT                              
030026,000166: 37,3265           72431                           VPROJ    VSL2                                  #  UNIT(P)=UNIT(UZ-(UZ)PROJ(UR))
030027,000167: 37,3266           00001                                    0D                                    
030028,000168: 37,3267           53445                           BVSU     UNIT                                  
030029,000169: 37,3270           00007                                    6D                                    
030030,000170: 37,3271           47315                           PDVL     VXV                                   #  UNIT(P) TO PD 12-17
030031,000171: 37,3272           00001                                    0D                                    #  UNIT(RL)
030032,000172: 37,3273           02215                                    VONE                                  

Page 706

030034,000174: 37,3274           50235                           VXV      DOT                                   #  (UR * VL) * UR . U(P)
030035,000175: 37,3275           00001                                    0D                                    
030036,000176: 37,3276           00015                                    12D                                   
030037,000177: 37,3277           77715                           PDVL                                           #  SIGN TO 12-13, LOAD U(P)
030038,000178: 37,3300           75241                           DOT      SIGN                                  
030039,000179: 37,3301           00007                                    6D                                    
030040,000180: 37,3302           00015                                    12D                                   
030041,000181: 37,3303           65512                           SL2      ACOS                                  #  ARCCOS(UP.UZ(SIGN))
030042,000182: 37,3304           26205                           STOVL    RTHETA                                
030043,000183: 37,3305           00001                                    0D                                    
030044,000184: 37,3306           51041                           DOT      BPL                                   #  IF UR.UZ NEG,
030045,000185: 37,3307           00007                                    6D                                    #        RTHETA = 1 - RTHETA
030046,000186: 37,3310           77315                                    +5                                    
030047,000187: 37,3311           45345                           DLOAD    DSU                                   
030048,000188: 37,3312           06532                                    DPPOSMAX                              
030049,000189: 37,3313           02205                                    RTHETA                                
030050,000190: 37,3314           02205                           STORE    RTHETA                                
030051,000191: 37,3315           77776                           EXIT                                           
030052,000192: 
030053,000193: 37,3316           34747                           CA       BIT5                                  
030054,000194: 37,3317           71043                           MASK     EXTVBACT                              
030055,000195: 37,3320           00006                           EXTEND                                         #  IF ANSWERED,
030056,000196: 37,3321           15472                           BZF      ENDEXT                                #        TERMINATE
030057,000197: 
030058,000198: 37,3322           41043                           CS       EXTVBACT                              
030059,000199: 37,3323           74740                           MASK     BIT12                                 
030060,000200: 37,3324           27043                           ADS      EXTVBACT                              #  SET BIT 12
030061,000201: 37,3325           13155                           TCF      REV83                                 #  AND START AGAIN.
030062,000202: 
030063,000203: 37,3326           37713        GETRVN             CA       PRIO22                                #  INHIBIT SERVICER
030064,000204: 37,3327           05146                           TC       PRIOCHNG                              
030065,000205: 37,3330           06042                           TC       INTPRET                               
030066,000206: 37,3331           40375                           VLOAD    SETPD                                 
030067,000207: 37,3332           01220                                    RN                                    #  LM STATE VECTOR IN RN,VN
030068,000208: 37,3333           00001                                    0                                     
030069,000209: 37,3334           26207                           STOVL    RONE                                  
030070,000210: 37,3335           01226                                    VN                                    
030071,000211: 37,3336           26215                           STOVL    VONE                                  #  LOAD R(CSM),V(CSM) IN CASE MUNFLAG SET
030072,000212: 37,3337           01726                                    V(CSM)                                #  (TO INSURE TIME COMPATABILITY)
030073,000213: 37,3340           65315                           PDVL     PDDL                                  
030074,000214: 37,3341           01720                                    R(CSM)                                
030075,000215: 37,3342           01234                                    PIPTIME                               
030076,000216: 37,3343           77776                           EXIT                                           
030077,000217: 37,3344           35015                           CA       PRIO3                                 
030078,000218: 37,3345           05146                           TC       PRIOCHNG                              
030079,000219: 37,3346           06042                           TC       INTPRET                               
030080,000220: 37,3347           77214                           BOFF     VLOAD                                 
030081,000221: 37,3350           03347                                    MUNFLAG                               
030082,000222: 37,3351           77363                                    GETRVN2                               #  IF MUNFLAG RESET, DO CM DELTA PRECISION

Page 707

030084,000224: 37,3352           60505                           VXM      VSR4                                  #  CHANGE TO REFERENCE SYSTEM AND RESCALE
030085,000225: 37,3353           01734                                    REFSMMAT                              
030086,000226: 37,3354           77715                           PDVL                                           #  R TO PD 0-5
030087,000227: 37,3355           76505                           VXM      VSL1                                  
030088,000228: 37,3356           01734                                    REFSMMAT                              
030089,000229: 37,3357           40206                           PUSH     SETPD                                 #  V TO PD 5-11
030090,000230: 37,3360           00001                                    0                                     
030091,000231: 37,3361           77650                           GOTO                                           
030092,000232: 37,3362           77240                                    COMPDISP                              
030093,000233: 
030094,000234: 37,3363           77624        GETRVN2            CALL                                           
030095,000235: 37,3364           27412                                    INTSTALL                              
030096,000236: 37,3365           52014                           CLEAR    GOTO                                  
030097,000237: 37,3366           01673                                    INTYPFLG                              #  PREC EXTRAP FOR OTHER
030098,000238: 37,3367           77222                                    OTHINT                                
030099,000239: 37,3370           06042        R31SURF            TC       INTPRET                               
030100,000240: 37,3371           77634                           RTB                                            #  LM IS ON SURFACE, SO PRECISION
030101,000241: 37,3372           21574                                    LOADTIME                              #  INTEGRATION USES PLANETARY INERTIAL
030102,000242: 37,3373           34041                           STCALL   TDEC1                                 #  ORIENTATION SUBROUTINE
030103,000243: 37,3374           27060                                    LEMPREC                               
030104,000244: 37,3375           77650                           GOTO                                           #  DO CSM CONIC
030105,000245: 37,3376           77211                                    OTHCONIC                              
030106,000246: 37,3377           40102        MUNG?              CS       FLAGWRD6                              
030107,000247: 37,3400           74744                           MASK     MUNFLBIT                              
030108,000248: 37,3401           00006                           EXTEND                                         
030109,000249: 37,3402           13326                           BZF      GETRVN                                #  IF MUNFLAG SET, CSM BASE NOT NEEDED
030110,000250: 
030111,000251: 37,3403           06042        ONEBASE            TC       INTPRET                               #  GET CSM BASE VECTOR
030112,000252: 37,3404           52034                           RTB      GOTO                                  
030113,000253: 37,3405           21574                                    LOADTIME                              
030114,000254: 37,3406           77144                                    DOCMBASE                              
030115,000255: 
030116,000256: 37,3407           04066        V16N54             VN       1654                                  
030117,000257: 

Page 708
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030120,000260: 

End of include-file R31.agc.  Parent file is MAIN.agc