Source Code

These source-code files derive from a printout of Luminary 210 (Apollo 15-17 Lunar Module guidance computer program), from the personal library of original AGC developer Don Eyles, digitally photographed at archive.org, financially sponsored by Jim Lawton, 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 210 OF AGC PROGRAM LUMINARY 
	BY NASA 2021112-161 17:11 MAR. 19,1971
Note that the date is the date of the printout, not the date of the program revision.

060233,000002:                                                                                                  ## Copyright:   Public domain.
060234,000003:                                                                                                  ## Filename:    RTB_OP_CODES.agc
060235,000004:                                                                                                  ## Purpose:     A section of Luminary revision 210.
060236,000005:                                                                                                  ##              It is part of the source code for the Lunar Module's (LM)
060237,000006:                                                                                                  ##              Apollo Guidance Computer (AGC) for Apollo 15-17.
060238,000007:                                                                                                  ##              This file is intended to be a faithful transcription, except
060239,000008:                                                                                                  ##              that the code format has been changed to conform to the
060240,000009:                                                                                                  ##              requirements of the yaYUL assembler rather than the
060241,000010:                                                                                                  ##              original YUL assembler.
060242,000011:                                                                                                  ## Reference:   pp. 1394-1399
060243,000012:                                                                                                  ## Assembler:   yaYUL
060244,000013:                                                                                                  ## Contact:     Ron Burkey <info@sandroid.org>.
060245,000014:                                                                                                  ## Website:     www.ibiblio.org/apollo/index.html
060246,000015:                                                                                                  ## Mod history: 2016-11-17 JL   Created from Luminary131 version.
060247,000016:                                                                                                  ##              2016-12-06 RRB  Updated from Luminary210 scans.
060248,000017:                                                                                                  ##              2016-12-09 HG   Add missing SETLOC RTBCODES (changes to Bank 10, because Bank 14 is full)
060249,000018:                                                                                                  ##              2016-12-26 RSB  Comment-text proofed using ProoferComments
060250,000019:                                                                                                  ##                              and corrected errors found.
060251,000020: 

Page 1394

060253,000022: 22,3774                                           BANK     22                                    
060254,000023: 10,2000                                           SETLOC   RTBCODES                              
060255,000024: 10,2000                                           BANK                                           
060256,000025: 
060257,000026: 10,3603  E5,1664                                  EBANK=   XNB                                   
060258,000027: 10,3603                                           COUNT*   $$/RTB                                
060259,000028: 
060260,000029:                                                                                                  #        LOAD TIME2, TIME1 INTO MPAC:
060261,000030: 
060262,000031: 10,3603           00006        LOADTIME           EXTEND                                         
060263,000032: 10,3604           30025                           DCA      TIME2                                 
060264,000033: 10,3605           16076                           TCF      SLOAD2                                
060265,000034: 
060266,000035:                                                                                                  #        CONVERT THE SINGLE PRECISION 2'S COMPLEMENT NUMBER ARRIVING IN MPAC (SCALED IN HALF-REVOLUTIONS) TO A
060267,000036:                                                                                                  #  DP 1'S COMPLEMENT NUMBER SCALED IN REVOLUTIONS.
060268,000037: 
060269,000038: 10,3606           10154        CDULOGIC           CCS      MPAC                                  
060270,000039: 10,3607           34746                           CAF      ZERO                                  
060271,000040: 10,3610           13613                           TCF      +3                                    
060272,000041: 10,3611           13612                           NOOP                                           
060273,000042: 10,3612           44727                           CS       HALF                                  
060274,000043: 
060275,000044: 10,3613           54155                           TS       MPAC       +1                         
060276,000045: 10,3614           34746                           CAF      ZERO                                  
060277,000046: 10,3615           56154                           XCH      MPAC                                  
060278,000047: 10,3616           00006                           EXTEND                                         
060279,000048: 10,3617           74727                           MP       HALF                                  
060280,000049: 10,3620           20155                           DAS      MPAC                                  
060281,000050: 10,3621           16102                           TCF      DANZIG                                #  MODE IS ALREADY AT DOUBLE-PRECISION
060282,000051: 
060283,000052:                                                                                                  #        FORCE TP SIGN AGREEMENT IN MPAC:
060284,000053: 
060285,000054: 10,3622           07300        SGNAGREE           TC       TPAGREE                               
060286,000055: 10,3623           16102                           TCF      DANZIG                                
060287,000056: 
060288,000057:                                                                                                  #        CONVERT THE DP 1'S COMPLEMENT ANGLE SCALED IN REVOLUTIONS TO A SINGLE PRECISION 2'S COMPLEMENT ANGLE
060289,000058:                                                                                                  #  SCALED IN HALF-REVOLUTIONS.
060290,000059: 
060291,000060: 10,3624           03654        1STO2S             TC       1TO2SUB                               
060292,000061: 10,3625           34746                           CAF      ZERO                                  
060293,000062: 10,3626           54155                           TS       MPAC       +1                         
060294,000063: 10,3627           16101                           TCF      NEWMODE                               
060295,000064: 
060296,000065:                                                                                                  #        DO 1STO2S ON A VECTOR OF ANGLES:
060297,000066: 
060298,000067: 10,3630           03654        V1STO2S            TC       1TO2SUB                               #  ANSWER ARRIVES IN A AND MPAC.
060299,000068: 
060300,000069: 10,3631           52162                           DXCH     MPAC       +5                         
060301,000070: 10,3632           52155                           DXCH     MPAC                                  
060302,000071: 10,3633           03654                           TC       1TO2SUB                               

Page 1395

060304,000073: 10,3634           54156                           TS       MPAC       +2                         
060305,000074: 
060306,000075: 10,3635           52160                           DXCH     MPAC       +3                         
060307,000076: 10,3636           52155                           DXCH     MPAC                                  
060308,000077: 10,3637           03654                           TC       1TO2SUB                               
060309,000078: 10,3640           54155                           TS       MPAC       +1                         
060310,000079: 
060311,000080: 10,3641           30161                           CA       MPAC       +5                         
060312,000081: 10,3642           54154                           TS       MPAC                                  
060313,000082: 
060314,000083: 10,3643           34744        TPMODE             CAF      ONE                                   #  MODE IS TP.
060315,000084: 10,3644           16101                           TCF      NEWMODE                               
060316,000085: 
060317,000086:                                                                                                  #        V1STO2S FOR 2 COMPONENT VECTOR. USED BY RR.
060318,000087: 
060319,000088: 10,3645           03654        2V1STO2S           TC       1TO2SUB                               
060320,000089: 10,3646           52160                           DXCH     MPAC       +3                         
060321,000090: 10,3647           52155                           DXCH     MPAC                                  
060322,000091: 10,3650           03654                           TC       1TO2SUB                               
060323,000092: 10,3651           54001                           TS       L                                     
060324,000093: 10,3652           30157                           CA       MPAC       +3                         
060325,000094: 10,3653           16076                           TCF      SLOAD2                                
060326,000095: 
060327,000096:                                                                                                  #        SUBROUTINE TO DO DOUBLING AND 1'S TO 2'S CONVERSION:
060328,000097: 
060329,000098: 10,3654           52155        1TO2SUB            DXCH     MPAC                                  #  FINAL MPAC +1 UNSPECIFIED.
060330,000099: 10,3655           20001                           DDOUBL                                         
060331,000100: 10,3656           10000                           CCS      A                                     
060332,000101: 10,3657           64744                           AD       ONE                                   
060333,000102: 10,3660           13662                           TCF      +2                                    
060334,000103: 10,3661           40000                           COM                                            #  THIS WAS REVERSE OF MSU.
060335,000104: 
060336,000105: 10,3662           54154                           TS       MPAC                                  #  AND SKIP ON OVERFLOW.
060337,000106: 10,3663           00002                           TC       Q                                     
060338,000107: 
060339,000108: 10,3664           50000                           INDEX    A                                     #  OVERFLOW UNCORRECT AND IN MSU.
060340,000109: 10,3665           34725                           CAF      LIMITS                                
060341,000110: 10,3666           26154                           ADS      MPAC                                  
060342,000111: 10,3667           00002                           TC       Q                                     
060343,000112: 
060344,000113:                                                                                                  #        THE FOLLOWING ROUTINE INCREMENTS IN 2S COMPLEMENT THE REGISTER WHOSE ADDRESS IS IN BUF BY THE 1S COMPL.
060345,000114:                                                                                                  #  QUANTITY FOUND IN TEM2.  THIS MAY BE USED TO INCREMENT DESIRED IMU AND OPTICS CDU ANGLES OR ANY OTHER 2S COMPL.
060346,000115:                                                                                                  #  (+0 UNEQUAL TO -0) QUANTITY.  MAY BE CALLED BY BANKCALL/SWCALL.
060347,000116: 
060348,000117: 10,3670           54142        CDUINC             TS       TEM2                                  #  1S COMPL.QUANT. ARRIVES IN ACC.  STORE IT
060349,000118: 10,3671           50130                           INDEX    BUF                                   
060350,000119: 10,3672           10000                           CCS      0                                     #  CHANGE 2S COMPL. ANGLE(IN BUF)INTO 1S
060351,000120: 10,3673           64744                           AD       ONE                                   
060352,000121: 10,3674           13700                           TCF      +4                                    
060353,000122: 10,3675           64744                           AD       ONE                                   

Page 1396

060355,000124: 10,3676           64744                           AD       ONE                                   #  OVERFLOW HERE IF 2S COMPL. IS 180 DEG.
060356,000125: 10,3677           40000                           COM                                            
060357,000126: 
060358,000127: 10,3700           60142                           AD       TEM2                                  #  SULT MOVES FROM 2ND TO 3D QUAD. (OR BACK)
060359,000128: 10,3701           10000                           CCS      A                                     #  BACK TO 2S COMPL.
060360,000129: 10,3702           64744                           AD       ONE                                   
060361,000130: 10,3703           13705                           TCF      +2                                    
060362,000131: 10,3704           40000                           COM                                            
060363,000132: 10,3705           54142                           TS       TEM2                                  #  STORE 14BIT QUANTITY WITH PRESENT SIGN
060364,000133: 10,3706           13712                           TCF      +4                                    
060365,000134: 10,3707           50000                           INDEX    A                                     #   SIGN.
060366,000135: 10,3710           34725                           CAF      LIMITS                                #  FIX IT, BY ADDING IN 37777 OR 40000
060367,000136: 10,3711           60142                           AD       TEM2                                  
060368,000137: 
060369,000138: 10,3712           50130                           INDEX    BUF                                   
060370,000139: 10,3713           54000                           TS       0                                     #  STORE NEW ANGLE IN 2S COMPLEMENT.
060371,000140: 10,3714           00002                           TC       Q                                     
060372,000141: 

Page 1397

060374,000143:                                                                                                  #        RTB TO TORQUE GYROS, EXCEPT FOR THE CALL TO IMUSTALL.  ECADR OF COMMANDS ARRIVES IN X1.
060375,000144: 
060376,000145: 10,3715           50120        PULSEIMU           INDEX    FIXLOC                                #  ADDRESS OF GYRO COMMANDS SHOULD BE IN X1
060377,000146: 10,3716           30046                           CA       X1                                    
060378,000147: 10,3717           04607                           TC       BANKCALL                              
060379,000148: 10,3720           17310                           CADR     IMUPULSE                              
060380,000149: 10,3721           16102                           TCF      DANZIG                                
060381,000150: 

Page 1398

060383,000152:                                                                                                  #        THE SUBROUTINE SIGNMPAC SETS C(MPAC, MPAC +1) TO SIGN(MPAC).
060384,000153:                                                                                                  #  FOR THIS, ONLY THE CONTENTS OF MPAC ARE EXAMINED.  ALSO +0 YIELDS POSMAX AND -0 YIELDS NEGMAX.
060385,000154: 
060386,000155:                                                                                                  #  ENTRY MAY BE BY EITHER OF THE FOLLOWING:
060387,000156:                                                                                                  #  1.    LIMIT THE SIZE OF MPAC ON INTERPRETIVE OVERFLOW:
060388,000157:                                                                                                  #  ENTRY:        BOVB
060389,000158:                                                                                                  #                        SIGNMPAC
060390,000159:                                                                                                  #  2.    GENERATE IN MPAC THE SIGNUM FUNCTION OF MPAC:
060391,000160:                                                                                                  #  ENTRY:        RTB
060392,000161:                                                                                                  #                                SIGNMPAC
060393,000162:                                                                                                  #  IN EITHER CASE, RETURN IS TO  THE NEXT INTERPRETIVE INSTRUCTION IN THE CALLING SEQUENCE.
060394,000163: 
060395,000164: 14,2000                                           SETLOC   RTBCODE1                              
060396,000165: 14,2000                                           BANK                                           
060397,000166: 
060398,000167: 14,3765           00006        SIGNMPAC           EXTEND                                         
060399,000168: 14,3766           34724                           DCA      DPOSMAX                               
060400,000169: 14,3767           52155                           DXCH     MPAC                                  
060401,000170: 14,3770           10000                           CCS      A                                     
060402,000171: 14,3771           34746        DPMODE             CAF      ZERO                                  #  SETS MPAC +2 TO ZERO IN THE PROCESS
060403,000172: 14,3772           16100                           TCF      SLOAD2     +2                         
060404,000173: 14,3773           13774                           TCF      +1                                    
060405,000174: 14,3774           00006                           EXTEND                                         
060406,000175: 14,3775           44724                           DCS      DPOSMAX                               
060407,000176: 14,3776           16076                           TCF      SLOAD2                                
060408,000177: 
060409,000178: 10,2000                                           SETLOC   RTBCODES                              
060410,000179: 10,2000                                           BANK                                           
060411,000180: 
060412,000181:                                                                                                  #        RTB OP CODE NORMUNIT IS LIKE INTERPRETIVE INSTRUCTION UNIT, EXCEPT THAT IT CAN BE DEPENDED ON NOT TO BLOW
060413,000182:                                                                                                  #  UP WHEN THE VECTOR BEING UNITIZED IS VERY SMALL -- IT WILL BLOW UP WHEN ALL COMPONENTS ARE ZERO.  IF NORMUNIT
060414,000183:                                                                                                  #  IS USED AND THE UPPER ORDER HALVES OF ALL COMPONENTS ARE ZERO, THE MAGNITUDE RETURNED IN 36D WILL BE TOO LARGE
060415,000184:                                                                                                  #  BY A FACTOR OF 2(13) AND THE SQUARED MAGNITUDE RETURNED AT 34D WILL BE TOO BIG BY A FACTOR OF 2(26).
060416,000185: 
060417,000186: 10,3722           34744        NORMUNX1           CAF      ONE                                   
060418,000187: 10,3723           13725                           TCF      NORMUNIT   +1                         
060419,000188: 10,3724           34746        NORMUNIT           CAF      ZERO                                  
060420,000189: 10,3725           60120                           AD       FIXLOC                                
060421,000190: 10,3726           54156                           TS       MPAC       +2                         
060422,000191: 10,3727           04607                           TC       BANKCALL                              #  GET SIGN AGREEMENT IN ALL COMPONENTS
060423,000192: 10,3730           01010                           CADR     VECAGREE                              
060424,000193: 10,3731           10154                           CCS      MPAC                                  
060425,000194: 10,3732           13766                           TCF      NOSHIFT                               
060426,000195: 10,3733           13735                           TCF      +2                                    
060427,000196: 10,3734           13766                           TCF      NOSHIFT                               
060428,000197: 10,3735           10157                           CCS      MPAC       +3                         
060429,000198: 10,3736           13766                           TCF      NOSHIFT                               

Page 1399

060431,000200: 10,3737           13741                           TCF      +2                                    
060432,000201: 10,3740           13766                           TCF      NOSHIFT                               
060433,000202: 10,3741           10161                           CCS      MPAC       +5                         
060434,000203: 10,3742           13766                           TCF      NOSHIFT                               
060435,000204: 10,3743           13745                           TCF      +2                                    
060436,000205: 10,3744           13766                           TCF      NOSHIFT                               
060437,000206: 10,3745           30155                           CA       MPAC       +1                         #  SHIFT ALL COMPONENTS LEFT 13
060438,000207: 10,3746           00006                           EXTEND                                         
060439,000208: 10,3747           74727                           MP       BIT14                                 
060440,000209: 10,3750           20155                           DAS      MPAC                                  #  DAS GAINS A LITTLE ACCURACY
060441,000210: 10,3751           30160                           CA       MPAC       +4                         
060442,000211: 10,3752           00006                           EXTEND                                         
060443,000212: 10,3753           74727                           MP       BIT14                                 
060444,000213: 10,3754           20160                           DAS      MPAC       +3                         
060445,000214: 10,3755           30162                           CA       MPAC       +6                         
060446,000215: 10,3756           00006                           EXTEND                                         
060447,000216: 10,3757           74727                           MP       BIT14                                 
060448,000217: 10,3760           20162                           DAS      MPAC       +5                         
060449,000218: 10,3761           34752                           CAF      THIRTEEN                              
060450,000219: 10,3762           50156                           INDEX    MPAC       +2                         
060451,000220: 10,3763           54045                           TS       37D                                   
060452,000221: 10,3764           04626        OFFTUNIT           TC       POSTJUMP                              
060453,000222: 10,3765           01024                           CADR     UNIT       +1                         #  SKIP THE "TC VECAGREE" DONE AT UNIT
060454,000223: 
060455,000224: 10,3766           34746        NOSHIFT            CAF      ZERO                                  
060456,000225: 10,3767           13762                           TCF      OFFTUNIT   -2                         
060457,000226: 
060458,000227:                                                                                                  #  RTB VECSGNAG ... FORCES SIGN AGREEMENT OF VECTOR IN MPAC.
060459,000228: 
060460,000229: 10,3770           04607        VECSGNAG           TC       BANKCALL                              
060461,000230: 10,3771           01010                           CADR     VECAGREE                              
060462,000231: 10,3772           06102                           TC       DANZIG                                
060463,000232: 

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