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.

020817,000002:                                                                                                  ## Copyright:   Public domain.
020818,000003:                                                                                                  ## Filename:    S-BAND_ANTENNA_FOR_LM.agc
020819,000004:                                                                                                  ## Purpose:     A section of Luminary revision 116.
020820,000005:                                                                                                  ##              It is part of the source code for the Lunar Module's (LM)
020821,000006:                                                                                                  ##              Apollo Guidance Computer (AGC) for Apollo 12.
020822,000007:                                                                                                  ##              This file is intended to be a faithful transcription, except
020823,000008:                                                                                                  ##              that the code format has been changed to conform to the
020824,000009:                                                                                                  ##              requirements of the yaYUL assembler rather than the
020825,000010:                                                                                                  ##              original YUL assembler.
020826,000011:                                                                                                  ## Reference:   pp. 488-491
020827,000012:                                                                                                  ## Assembler:   yaYUL
020828,000013:                                                                                                  ## Contact:     Ron Burkey <info@sandroid.org>.
020829,000014:                                                                                                  ## Website:     www.ibiblio.org/apollo/index.html
020830,000015:                                                                                                  ## Mod history: 2017-01-22 MAS  Created from Luminary 99.
020831,000016:                                                                                                  ##              2017-03-09 RSB  Transcribed, and then proofed comment-text using
020832,000017:                                                                                                  ##                              3-way diff vs Luminary 99 and Luminary 131.
020833,000018:                                                                                                  ##                              (Admittedly, the former is more for detecting errors
020834,000019:                                                                                                  ##                              in Luminary 99 than the other way around.)
020835,000020:                                                                                                  ##              2017-03-13 HG   Remove operand modifier SBANDANT +2 --> SBANDANT
020836,000021: 

Page 488

020838,000023:                                                                                                  #  SUBROUTINE NAME: R05 - S-BAND ANTENNA FOR LM
020839,000024: 
020840,000025:                                                                                                  #  MOD0 BY T. JAMES
020841,000026:                                                                                                  #  MOD1 BY P. SHAKIR
020842,000027: 
020843,000028:                                                                                                  #  FUNCTIONAL DESCRIPTION
020844,000029: 
020845,000030:                                                                                                  #  THE S-BAND ANTENNA ROUTINE, R05, COMPUTES AND DISPLAYS THE PITCH AND
020846,000031:                                                                                                  #  YAW ANTENNA GIMBAL ANGLES REQUIRED TO POINT THE LM STEERABLE ANTENNA
020847,000032:                                                                                                  #  TOWARD THE CENTER OF THE EARTH.  THIS ROUTINE IS SELECTED BY THE ASTRO-
020848,000033:                                                                                                  #  NAUT VIA DSKY ENTRY DURING COASTING FLIGHT OR WHEN THE LM IS ON THE MOON
020849,000034:                                                                                                  #  SURFACE.  THE EARTH OR MOON REFERENCE COORDINATE SYSTEM IS USED DEPENDING
020850,000035:                                                                                                  #  ON WHETHER THE LM IS ABOUT TO ENTER OR HAS ALREADY ENTERED THE MOON
020851,000036:                                                                                                  #  SPHERE OF INFLUENCE, RESPECTIVELY.  CAN BE CALLED ANY TIME EXCEPT WHEN
020852,000037:                                                                                                  #  ANOTHER EXTENDED VERB IS IN USE. DISPLAY IS MEANINGLESS WITH IMU OFF.
020853,000038: 
020854,000039:                                                                                                  #  TO CALL SUBROUTINE, ASTRONAUT KEYS IN V 64 E
020855,000040: 
020856,000041:                                                                                                  #  SUBROUTINES CALLED -
020857,000042: 
020858,000043:                                                                                                  #        INTPRET
020859,000044:                                                                                                  #        LOADTIME
020860,000045:                                                                                                  #        LEMCONIC
020861,000046:                                                                                                  #        LUNPOS
020862,000047:                                                                                                  #        CDUTRIG
020863,000048:                                                                                                  #        *SMNB*
020864,000049:                                                                                                  #        BANKCALL
020865,000050:                                                                                                  #        B5OFF
020866,000051:                                                                                                  #        ENDOFJOB
020867,000052:                                                                                                  #        BLANKET
020868,000053: 
020869,000054:                                                                                                  #  RETURNS WITH
020870,000055: 
020871,000056:                                                                                                  #        PITCH ANGLE IN PITCHANG         REV. B0
020872,000057:                                                                                                  #        YAW ANGLE IN YAWANG             REV. B0
020873,000058: 
020874,000059:                                                                                                  #  ERASABLES USED
020875,000060:                                                                                                  #        PITCHANG
020876,000061:                                                                                                  #        YAWANG
020877,000062:                                                                                                  #        RLM
020878,000063:                                                                                                  #        VAC AREA
020879,000064: 
020880,000065: 41,3743                                           BANK     41                                    
020881,000066: 42,2000                                           SETLOC   SBAND                                 
020882,000067: 42,2000                                           BANK                                           
020883,000068: 
020884,000069: 42,3606  E7,1471                                  EBANK=   WHOCARES                              
020885,000070: 42,3606                                           COUNT*   $$/R05                                
020886,000071: 42,3606           06042        SBANDANT           TC       INTPRET                               

Page 489

020888,000073: 42,3607           47001                           SETPD    RTB                                   
020889,000074: 42,3610           00001                                    0D                                    
020890,000075: 42,3611           21574                                    LOADTIME                              #  PICK UP CURRENT TIME
020891,000076: 42,3612           34041                           STCALL   TDEC1                                 #  ADVANCE INTEGRATION TO TIME IN TDEC1
020892,000077: 42,3613           27101                                    LEMCONIC                              #  USING CONIC INTEGRATION
020893,000078: 42,3614           46135                           SLOAD    BHIZ                                  
020894,000079: 42,3615           00050                                    X2                                    #  X2 =0 EARTH SPHERE, X2 =2 MOON SPHERE
020895,000080: 42,3616           65634                                    CONV4                                 
020896,000081: 42,3617           77775                           VLOAD                                          
020897,000082: 42,3620           00001                                    RATT                                  
020898,000083: 42,3621           16205                           STODL    RLM                                   
020899,000084: 42,3622           00015                                    TAT                                   
020900,000085: 42,3623           77624        CONV3              CALL                                           
020901,000086: 42,3624           33647                                    LUNPOS                                #  UNIT POSITION VECTOR FROM EARTH TO MOON
020902,000087: 42,3625           74375                           VLOAD    VXSC                                  
020903,000088: 42,3626           02723                                    VMOON                                 
020904,000089: 42,3627           24001                                    REMDIST                               #  MEAN DISTANCE FROM EARTH TO MOON
020905,000090: 42,3630           53372                           VSL1     VAD                                   
020906,000091: 42,3631           02205                                    RLM                                   
020907,000092: 42,3632           77650                           GOTO                                           
020908,000093: 42,3633           65636                                    CONV5                                 
020909,000094: 42,3634           77775        CONV4              VLOAD                                          
020910,000095: 42,3635           00001                                    RATT                                  #  UE = -UNIT(RATT)              EARTH SPHERE
020911,000096: 42,3636           53401        CONV5              SETPD    UNIT                                  #  UE = -UNIT((REM)(UEM) + RL)   MOON SPHERE
020912,000097: 42,3637           00001                                    0D                                    #  SET PL POINTER TO 0
020913,000098: 42,3640           45076                           VCOMP    CALL                                  
020914,000099: 42,3641           47541                                    CDUTRIG                               #  COMPUTE SINES AND COSINES OF CDU ANGLES
020915,000100: 42,3642           76521                           MXV      VSL1                                  #  TRANSFORM REF. COORDINATE SYSTEM TO
020916,000101: 42,3643           01734                                    REFSMMAT                              #  STABLE MEMBER B-1 X B-1 X B+1 = B-1
020917,000102: 42,3644           71206                           PUSH     DLOAD                                 #  8D
020918,000103: 42,3645           06524                                    HI6ZEROS                              
020919,000104: 42,3646           02201                           STORE    PITCHANG                              
020920,000105: 42,3647           26203                           STOVL    YAWANG                                #  ZERO OUT ANGLES
020921,000106: 42,3650           77624                           CALL                                           
020922,000107: 42,3651           47673                                    *SMNB*                                
020923,000108: 42,3652           16205                           STODL    RLM                                   #  PRE-MULTIPLY RLM BY (NBSA) MATRIX(B0)
020924,000109: 42,3653           02207                                    RLM        +2                         
020925,000110: 42,3654           45206                           PUSH     DSU                                   
020926,000111: 42,3655           02205                                    RLM                                   
020927,000112: 42,3656           77605                           DMP                                            
020928,000113: 42,3657           25767                                    1OVSQRT2                              
020929,000114: 42,3660           16207                           STODL    RLM        +2                         
020930,000115: 42,3661           41215                           DAD      DMP                                   
020931,000116: 42,3662           02205                                    RLM                                   
020932,000117: 42,3663           25767                                    1OVSQRT2                              
020933,000118: 42,3664           26205                           STOVL    RLM                                   #  R B-1
020934,000119: 42,3665           02205                                    RLM                                   
020935,000120: 42,3666           63256                           UNIT     PDVL                                  
020936,000121: 42,3667           02205                                    RLM                                   
020937,000122: 42,3670           72431                           VPROJ    VSL2                                  #  PROJECTION OF R ONTO LM XZ PLANE

Page 490

020939,000124: 42,3671           06520                                    HIUNITY                               
020940,000125: 42,3672           40045                           BVSU     BOV                                   #  CLEAR OVERFLOW INDICATOR IF ON
020941,000126: 42,3673           02205                                    RLM                                   
020942,000127: 42,3674           65675                                    COVCNV                                
020943,000128: 42,3675           40056        COVCNV             UNIT     BOV                                   #  EXIT ON OVERFLOW
020944,000129: 42,3676           65743                                    SBANDEX                               
020945,000130: 42,3677           47206                           PUSH     VXV                                   #  URP VECTOR B-1
020946,000131: 42,3700           06516                                    HIUNITZ                               
020947,000132: 42,3701           57572                           VSL1     VCOMP                                 #  UZ X URP = -(URP X UZ)
020948,000133: 42,3702           02205                           STORE    RLM                                   #  X VEC B-1
020949,000134: 42,3703           63241                           DOT      PDVL                                  #  SGN(X.UY) UNSCALED
020950,000135: 42,3704           06520                                    HIUNITY                               
020951,000136: 42,3705           02205                                    RLM                                   
020952,000137: 42,3706           75246                           ABVAL    SIGN                                  
020953,000138: 42,3707           77736                           ASIN                                           #  ASIN((SGN(X.UY))ABV(X))       REV B0
020954,000139: 42,3710           26201                           STOVL    PITCHANG                              
020955,000140: 42,3711           00007                                    URP                                   
020956,000141: 42,3712           51041                           DOT      BPL                                   
020957,000142: 42,3713           06516                                    HIUNITZ                               
020958,000143: 42,3714           65721                                    NOADJUST                              #  YES, -90 TO +90
020959,000144: 42,3715           45345                           DLOAD    DSU                                   
020960,000145: 42,3716           06522                                    HIDPHALF                              
020961,000146: 42,3717           02201                                    PITCHANG                              
020962,000147: 42,3720           02201                           STORE    PITCHANG                              
020963,000148: 42,3721           47375        NOADJUST           VLOAD    VXV                                   
020964,000149: 42,3722           00001                                    UR                                    #  Z = (UR X URP)
020965,000150: 42,3723           00007                                    URP                                   
020966,000151: 42,3724           77772                           VSL1                                           
020967,000152: 42,3725           16205                           STODL    RLM                                   #  Z VEC B-1
020968,000153: 42,3726           02201                                    PITCHANG                              
020969,000154: 42,3727           74356                           SIN      VXSC                                  
020970,000155: 42,3730           06516                                    HIUNITZ                               
020971,000156: 42,3731           71525                           PDDL     COS                                   
020972,000157: 42,3732           02201                                    PITCHANG                              
020973,000158: 42,3733           52361                           VXSC     VSU                                   
020974,000159: 42,3734           06522                                    HIUNITX                               #  (UX COS ALPHA) - (UZ SIN ALPHA)
020975,000160: 42,3735           63241                           DOT      PDVL                                  #  YAW.Z
020976,000161: 42,3736           02205                                    RLM                                   
020977,000162: 42,3737           02205                                    RLM                                   
020978,000163: 42,3740           75246                           ABVAL    SIGN                                  
020979,000164: 42,3741           77736                           ASIN                                           
020980,000165: 42,3742           02203                           STORE    YAWANG                                
020981,000166: 42,3743           77776        SBANDEX            EXIT                                           
020982,000167: 42,3744           31043                           CA       EXTVBACT                              
020983,000168: 42,3745           74747                           MASK     BIT5                                  #  IS BIT5 STILL ON
020984,000169: 42,3746           00006                           EXTEND                                         
020985,000170: 42,3747           15472                           BZF      ENDEXT                                #  NO
020986,000171: 42,3750           35017                           CAF      PRIO5                                 
020987,000172: 42,3751           05146                           TC       PRIOCHNG                              
020988,000173: 42,3752           33765                           CAF      V06N51                                #  DISPLAY ANGLES

Page 491

020990,000175: 42,3753           04616                           TC       BANKCALL                              
020991,000176: 42,3754           20353                           CADR     GOMARKFR                              
020992,000177: 42,3755           05563                           TC       B5OFF                                 #  TERMINATE
020993,000178: 42,3756           05563                           TC       B5OFF                                 #  PROCEED
020994,000179: 42,3757           05155                           TC       ENDOFJOB                              #  RECYCLE
020995,000180: 42,3760           34751                           CAF      BIT3                                  #  IMMEDIATE RETURN
020996,000181: 42,3761           05464                           TC       BLANKET                               #  BLANK R3
020997,000182: 42,3762           34740                           CAF      PRIO4                                 
020998,000183: 42,3763           05146                           TC       PRIOCHNG                              
020999,000184: 42,3764           03606                           TC       SBANDANT                              #  YES, CONTINUE DISPLAYING ANGLES.
021000,000185: 42,3765           01463        V06N51             VN       0651                                  
021001,000186: 42,3766           26501 07463  1OVSQRT2           2DEC     .7071067815                            #  1/SQRT(2)
021002,000187: 
021003,000188: 42,3770                        UR                 EQUALS   0D                                    
021004,000189: 42,3770                        URP                EQUALS   6D                                    
021005,000190: 42,3770  30,2000                                  SBANK=   LOWSUPER                              

End of include-file S-BAND_ANTENNA_FOR_LM.agc.  Parent file is MAIN.agc