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.

014089,000002:                                                                                                  ## Copyright:   Public domain.
014090,000003:                                                                                                  ## Filename:    R63.agc
014091,000004:                                                                                                  ## Purpose:     A section of Luminary revision 116.
014092,000005:                                                                                                  ##              It is part of the source code for the Lunar Module's (LM) 
014093,000006:                                                                                                  ##              Apollo Guidance Computer (AGC) for Apollo 12.
014094,000007:                                                                                                  ##              This file is intended to be a faithful transcription, except
014095,000008:                                                                                                  ##              that the code format has been changed to conform to the
014096,000009:                                                                                                  ##              requirements of the yaYUL assembler rather than the
014097,000010:                                                                                                  ##              original YUL assembler.
014098,000011:                                                                                                  ## Reference:   pp. 339-342
014099,000012:                                                                                                  ## Assembler:   yaYUL
014100,000013:                                                                                                  ## Contact:     Ron Burkey <info@sandroid.org>.
014101,000014:                                                                                                  ## Website:     www.ibiblio.org/apollo/index.html
014102,000015:                                                                                                  ## Mod history: 2017-01-22 MAS  Created from Luminary 99.
014103,000016:                                                                                                  ##              2017-01-26 RSB  Back-ported a comment-text fix from Luminary 69.
014104,000017:                                                                                                  ## Mod history: 2017-01-22 MAS  Created from Luminary 99.
014105,000018:                                                                                                  ##              2017-03-07 RSB  Transcribed, and then proofed comment-text using
014106,000019:                                                                                                  ##                              3-way diff vs Luminary 99 and Luminary 131.
014107,000020:                                                                                                  ##                              (Admittedly, the former is more for detecting errors
014108,000021:                                                                                                  ##                              in Luminary 99 than the other way around.)
014109,000022: 

Page 339

014111,000024:                                                                                                  #  SUBROUTINE NAME:      V89CALL
014112,000025:                                                                                                  #  MOD NO:       0                       DATE:           9 JAN 1968
014113,000026:                                                                                                  #  MOD BY:       DIGITAL DEVEL GROUP     LOG SECTION:    R63
014114,000027: 
014115,000028:                                                                                                  #  FUNCTIONAL DESCRIPTION:
014116,000029: 
014117,000030:                                                                                                  #  CALLED BY VERB 89 ENTER DURING P00.  PRIO 10 USED.  CALCULATES AND
014118,000031:                                                                                                  #  DISPLAYS FINAL FDAI BALL ANGLES TO POINT LM +X OR +Z AXIS AT CSM.
014119,000032: 
014120,000033:                                                                                                  #  1. KEY IN V 89 E ONLY IF IN PROG 00.  IF NOT IN P00, OPERATOR ERROR AND
014121,000034:                                                                                                  #  EXIT R63, OTHERWISE CONTINUE.
014122,000035: 
014123,000036:                                                                                                  #  2. IF IN P00, DO IMU STATUS CHECK ROUTINE (R02BOTH).  IF IMU ON AND ITS
014124,000037:                                                                                                  #  ORIENTATION KNOWN TO LGC, CONTINUE.
014125,000038: 
014126,000039:                                                                                                  #  3. FLASH DISPLAY V 04 N 06.  R2 INDICATES WHICH SPACECRAFT AXIS IS TO
014127,000040:                                                                                                  #  BE POINTED AT CSM.  INITIAL CHOICE IS PREFERRED (+Z) AXIS (R2=1).
014128,000041:                                                                                                  #  ASTRONAUT CAN CHANGE TO (+X) AXIS (R2 NOT =1) BY V 22 E 2 E.  CONTINUE
014129,000042:                                                                                                  #  AFTER KEYING IN PROCEED.
014130,000043: 
014131,000044:                                                                                                  #  4. BOTH VEHICLE STATE VECTORS UPDATED BY CONIC EQS.
014132,000045: 
014133,000046:                                                                                                  #  5. HALF MAGNITUDE UNIT LOS VECTOR (IN STABLE MEMBER COORDINATES) AND
014134,000047:                                                                                                  #  HALF MAGNITUDE UNIT SPACECRAFT AXIS VECTOR (IN BODY COORDINATES)
014135,000048:                                                                                                  #  PREPARED FOR VECPOINT.
014136,000049: 
014137,000050:                                                                                                  #  6. GIMBAL ANGLES FROM VECPOINT TRANSFORMED INTO FDAI BALL ANGLES BY
014138,000051:                                                                                                  #  BALLANGS. FLASH DISPLAY V 06 N 18 AND AWAIT RESPONSE.
014139,000052: 
014140,000053:                                                                                                  #  7.    RECYCLE - RETURN TO STEP 4.
014141,000054:                                                                                                  #        TERMINATE - EXIT R63.
014142,000055:                                                                                                  #        PROCEED - RESET 3AXISFLG AND CALL R60LEM FOR ATTITUDE MANEUVER.
014143,000056: 
014144,000057:                                                                                                  #  CALLING SEQUENCE:     V 89 E.
014145,000058: 
014146,000059:                                                                                                  #  SUBROUTINES CALLED:   CHKPOOH, R02BOTH, GOXDSPF, CSMCONIC, LEMCONIC,
014147,000060:                                                                                                  #                        VECPOINT, BALLANGS, R60LEM.
014148,000061: 
014149,000062:                                                                                                  #  NORMAL EXIT MODES:    TC ENDEXT
014150,000063: 
014151,000064:                                                                                                  #  ALARMS:       1. OPERATOR ERROR IF NOT IN P00.
014152,000065:                                                                                                  #                2. PROGRAM ALARM IF IMU IS OFF.
014153,000066:                                                                                                  #                3. PROGRAM ALARM IF IMU ORIENTATION IS UNKNOWN.
014154,000067: 
014155,000068:                                                                                                  #  OUTPUT:       NONE
014156,000069: 
014157,000070:                                                                                                  #  ERASABLE INITIALIZATION REQUIRED:  NONE
014158,000071: 
014159,000072:                                                                                                  #  DEBRIS:       OPTION1, +1, TDEC1, POINTVSM, SCAXIS, CPHI, CTHETA, CPSI,

Page 340

014161,000074:                                                                                                  #                3AXISFLG.
014162,000075: 
014163,000076: 06,3723  E4,1606                                  EBANK=   RONE                                  
014164,000077: 32,2217                                           BANK     32                                    
014165,000078: 26,2000                                           SETLOC   BAWLANGS                              
014166,000079: 26,2000                                           BANK                                           
014167,000080: 
014168,000081: 26,2022                                           COUNT*   $$/R63                                
014169,000082: 26,2022           04616        V89CALL            TC       BANKCALL                              #  IMU STATUS CHECK. RETURNS IF ORIENTATION
014170,000083: 26,2023           11236                           CADR     R02BOTH                               #  KNOWN. ALARMS IF NOT.
014171,000084: 26,2024           36250                           CAF      THREE                                 #  ALLOW ASTRONAUT TO SELECT DESIRED
014172,000085: 26,2025           55050                           TS       OPTIONX                               #  TRACKING ATTITUDE AXIS.
014173,000086: 26,2026           34753                           CAF      ONE                                   
014174,000087: 26,2027           55051                           TS       OPTIONX    +1                         
014175,000088: 26,2030           32117                           CAF      VB04N12                               #  V 04 N 12
014176,000089: 26,2031           04616                           TC       BANKCALL                              
014177,000090: 26,2032           20477                           CADR     GOFLASH                               
014178,000091: 26,2033           05472                           TC       ENDEXT                                #  TERMINATE
014179,000092: 26,2034           02036                           TC       +2                                    #  PROCEED
014180,000093: 26,2035           02030                           TC       -5                                    #  DATA IN. OPTION1+1 = 1 FOR Z AXIS
014181,000094: 26,2036           06042        V89RECL            TC       INTPRET                               #                    = 2 FOR X AXIS
014182,000095: 26,2037           43234                           RTB      DAD                                   
014183,000096: 26,2040           21574                                    LOADTIME                              #  READ PRESENT TIME
014184,000097: 26,2041           14122                                    DP1MIN                                
014185,000098: 26,2042           02205                           STORE    TSTART82                              #  SAVE TIME FOR LEMCONIC CALL
014186,000099: 26,2043           34041                           STCALL   TDEC1                                 #  STORE TIME FOR CSMCONIC CALL
014187,000100: 26,2044           27067                                    CSMCONIC                              #  CSM STATE VECTOR UPDATE
014188,000101: 26,2045           77775                           VLOAD                                          #  CSMCONIC LEFT R VECTOR IN RATT
014189,000102: 26,2046           00001                                    RATT                                  
014190,000103: 26,2047           16207                           STODL    RONE                                  #  SAVE FOR LINE OF SIGHT (LOS) COMPUTATION
014191,000104: 26,2050           02205                                    TSTART82                              
014192,000105: 26,2051           34041                           STCALL   TDEC1                                 #  STORE TIME FOR LEMCONIC CALL
014193,000106: 26,2052           27101                                    LEMCONIC                              #  LEM STATE VECTOR UPDATE
014194,000107: 26,2053           52375                           VLOAD    VSU                                   #  CSM POSITION - LEM POSITION = LOS
014195,000108: 26,2054           02207                                    RONE                                  #  LOS VECTOR LEFT IN MPAC
014196,000109: 26,2055           00001                                    RATT                                  
014197,000110: 26,2056           47121                           MXV      RTB                                   #  (REFSMMAT X LOS).  TRANSFORMS LOS FROM
014198,000111: 26,2057           01734                                    REFSMMAT                              #  REFERENCE COORD TO STAB MEMB COORD.
014199,000112: 26,2060           21727                                    NORMUNIT                              
014200,000113: 26,2061           03773                           STORE    POINTVSM                              #  STORE LOS FOR VECPOINT CALL
014201,000114: 26,2062           77776                           EXIT                                           
014202,000115: 26,2063           41051                           CS       OPTIONX    +1                         #  1 FOR Z AXIS. 2 FOR X AXIS.
014203,000116: 26,2064           64753                           AD       ONE                                   
014204,000117: 26,2065           00006                           EXTEND                                         
014205,000118: 26,2066           12113                           BZF      ALINEZ                                
014206,000119: 26,2067           06042        ALINEX             TC       INTPRET                               #  X AXIS ALIGNMENT
014207,000120: 26,2070           77775                           VLOAD                                          
014208,000121: 26,2071           06522                                    UNITX                                 #  READ (.5, 0, 0)

Page 341

014210,000123: 26,2072           37765        V89CALL1           STCALL   SCAXIS                                #  STORE SELECTED ALIGNMENT AXIS
014211,000124: 26,2073           56040                                    VECPOINT                              #  PUTS DESIRED GIM ANG (OG,IG,MG) IN TMPAC
014212,000125: 26,2074           00322                           STORE    CPHI                                  #  STORE GIMBAL ANGLES FOR BALLANGS CALL.
014213,000126: 26,2075           77776                           EXIT                                           
014214,000127: 26,2076           04616                           TC       BANKCALL                              
014215,000128: 26,2077           54272                           CADR     BALLANGS                              #  PUTS DESIRED BALL ANGLES IN FDAIX,Y,Z
014216,000129: 26,2100           32120                           CAF      VB06N18                               #  V 06 N 18
014217,000130: 26,2101           04616                           TC       BANKCALL                              #  NOUN 18 REFERS TO FDAIX,Y,Z
014218,000131: 26,2102           20477                           CADR     GOFLASH                               
014219,000132: 26,2103           05472                           TC       ENDEXT                                #  TERMINATE
014220,000133: 26,2104           02106                           TC       +2                                    #  PROCEED
014221,000134: 26,2105           02036                           TC       V89RECL                               #  RECYCLE
014222,000135: 26,2106           05516                           TC       DOWNFLAG                              #  RESET 3 AXIS FLAG
014223,000136: 26,2107           00124                           ADRES    3AXISFLG                              #  RESET BIT6 FLAG WORD 5
014224,000137: 26,2110           04616                           TC       BANKCALL                              #  PERFORMS LEM MANEUVER TO ALIGN SELECTED
014225,000138: 26,2111           54123                           CADR     R60LEM                                #  SPACECRAFT AXIS TO CSM.
014226,000139: 26,2112           15472                           TCF      ENDEXT                                #  TERMINATE R63
014227,000140: 
014228,000141: 26,2113           06042        ALINEZ             TC       INTPRET                               #  Z AXIS ALIGNMENT
014229,000142: 26,2114           52175                           VLOAD    GOTO                                  
014230,000143: 26,2115           06516                                    UNITZ                                 #  READ (0, 0, .5)
014231,000144: 26,2116           54072                                    V89CALL1                              
014232,000145: 
014233,000146: 26,2117           01014        VB04N12            VN       412                                   
014234,000147: 26,2120           01422        VB06N18            VN       0618                                  

Page 342

014236,000149: 26,2121           00000 13560  DP1MIN             2DEC     6000       B-28                       
014237,000150: 

End of include-file R63.agc.  Parent file is MAIN.agc