Source Code

These source-code files were transcribed from scans made from Don Eyles's personal copy of BURST120 (SUNBURST 120). They were scanned at archive.org's Boston facility, and the scanning was sponsored by Mike Stewart. The code was transcribed from these scans by a team of volunteers who are referenced in the program comments. Comments from the original source code are in ALL-CAPS, whereas comments added later in transcription are in Mixed-Case. In some cases, where similar code blocks exist in previously-transcribed AGC programs (primarily Luminary 99, from Apollo 11) those code blocks were used as a starting point and then corrected to agree with the BURST120 scans. The full scans are available at the Virtual AGC project's collection at archive.org, while more-convenient reduced-size (but reduced-quality) images are available at the main Virtual AGC website. Report any errors noted by creating an issue report at the Virtual AGC project's GitHub repository. Notations on the program listing read, in part:

	YUL SYSTEM FOR AGC: REVISION 0 OF PROGRAM BURST120 
	BY NASA 2021106-031 DEC 7, 1967

	THIS LISTING IS A COPY OF A VERSION OF THE PROGRAM INTENDED 
	FOR USE IN THE ON-BOARD PRIMARY GUIDANCE COMPUTER IN THE 
	UNMANNED FLIGHT OF APOLLO LUNAR MODULE 1 --- THE AS206 MISSION.
Note that the date is the date of the printout, not the date of the program revision.

039662,000002:                                                                                                  ## Copyright:   Public domain.
039663,000003:                                                                                                  ## Filename:    THRUST_MAGNITUDE_FILTER.agc
039664,000004:                                                                                                  ## Purpose:     A module for revision 0 of BURST120 (Sunburst). It 
039665,000005:                                                                                                  ##              is part of the source code for the Lunar Module's
039666,000006:                                                                                                  ##              (LM) Apollo Guidance Computer (AGC) for Apollo 5.
039667,000007:                                                                                                  ## Assembler:   yaYUL
039668,000008:                                                                                                  ## Contact:     Ron Burkey <info@sandroid.org>.
039669,000009:                                                                                                  ## Website:     www.ibiblio.org/apollo/index.html
039670,000010:                                                                                                  ## Mod history: 2016-09-30 RSB  Created draft version.
039671,000011:                                                                                                  ##              2016-10-19 RSB  Transcribed.
039672,000012:                                                                                                  ##              2016-10-31 RSB  Typos.
039673,000013:                                                                                                  ##              2016-12-06 RSB  Comment proofing via octopus/ProoferComments
039674,000014:                                                                                                  ##                              performed, and changes made.
039675,000015: 

Page 923

039677,000017:                                                                                                  #  PROGRAM NAME - ATMAG
039678,000018: 
039679,000019:                                                                                                  #  MODIFICATION BY - BERMAN AND CATTANACH
039680,000020: 
039681,000021:                                                                                                  #  FUNCTIONAL DESCRIPTION -
039682,000022: 
039683,000023:                                                                                                  #      THE THRUST MAGNITUDE FILTER CONVERTS ABDELV TO M/CS, INVERTS AND COMBINES IT WITH TWO PRECEDING
039684,000024:                                                                                                  #  INPUTS TO PRODUCE THE INVERTED EXHAUST VELOCITY, BURN UP TIME, AND ANTICIPATED THRUST ACCELERATION FOR
039685,000025:                                                                                                  #  THE NEXT TIME INCREMENT.  THRUST MAGNITUDE FILTER IS BYPASSED UNTIL AFTER THE MAIN ENGINE GOES ON.
039686,000026: 
039687,000027:                                                                                                  #  CALLING SEQUENCE - ATMAG IS ENTERED BY EXTEND                 AND        EXTEND
039688,000028:                                                                                                  #                                       DCA      ATMAGAD                   DCA     ATMAG4
039689,000029:                                                                                                  #                                       DXCH     AVGEXIT                   DXCH    AVGEXIT
039690,000030:                                                                                                  #  NORMAL EXIT - FROM ATMAG BY GOTO
039691,000031:                                                                                                  #                                   ASCENT
039692,000032: 
039693,000033:                                                                                                  #  OUTPUT - INVERTED EXHAUST VELOCITY, BURN UP TIME, AND ANTICIPATED THRUST ACCELERATION
039694,000034: 
039695,000035:                                                                                                  #  ERASABLE INITIALIZATION REQUIRED - THIS IS DONE BY PRE-APS PROGRAMS
039696,000036: 
039697,000037:                                                                                                  #  DEBRIS - ABDVCONV, 1/DV1, 1/DV2, 1/VE, TBUP, AT.
039698,000038: 
039699,000039:                                                                                                  #  ALARM OR ABORT EXIT MODES - 
039700,000040: 
039701,000041:                                                                                                  #  SUBROUTINES CALLED - NONE
039702,000042: 
039703,000043: 32,3005                                           BANK     32                                    
039704,000044: 
039705,000045: 32,3005  E4,1452                                  EBANK=   TCO                                   #  EBANK4
039706,000046: 
039707,000047: 32,3005           06112        ATMAG              TC       INTPRET                               
039708,000048: 32,3006           57545                           DLOAD    DCOMP                                 #  LOAD -VE*2(-6)
039709,000049: 32,3007           02556                                    NEGVEX                                
039710,000050: 32,3010           77742                           SR1                                            
039711,000051: 32,3011           02025                           STORE    VE                                    #  VE*2(-7)
039712,000052: 32,3012           67201                           SETPD    SLOAD                                 
039713,000053: 32,3013           00001                                    00D                                   
039714,000054: 32,3014           25052                                    BIT4H                                 
039715,000055: 32,3015           77471                           DDV      EXIT                                  
039716,000056: 32,3016           03624                                    ABDVCONV                              
039717,000057: 
039718,000058: 32,3017           52145                           DXCH     MPAC                                  
039719,000059: 32,3020           53435                           DXCH     1/DV3                                 
039720,000060: 32,3021           53433                           DXCH     1/DV2                                 
039721,000061: 32,3022           53431                           DXCH     1/DV1                                 
039722,000062: 32,3023           52145                           DXCH     MPAC                                  #  MPAC=1/DV0*2(-7)
039723,000063: 32,3024           06112                           TC       INTPRET                               
039724,000064: 32,3025           77615                           DAD                                            
039725,000065: 32,3026           02031                                    1/DV1                                 #  (1/DV0+1/DV1)*2(-7)
039726,000066: 32,3027           43215                           DAD      DAD                                   

Page 924

039728,000068: 32,3030           02033                                    1/DV2                                 
039729,000069: 32,3031           02035                                    1/DV3                                 #  SUM(1/DV)*2(-7)
039730,000070: 32,3032           41205                           DMP      DMP                                   #  VE SUM(1/DV)*2(-14)
039731,000071: 32,3033           02025                                    VE                                    #  DT VE SUM(1/DV)*2(-21)
039732,000072: 32,3034           21400                                    2SEC(9)                               
039733,000073: 32,3035           65252                           SL3      PDDL                                  #  1/8 DT VE SUM(1/DV)*2(-17)
039734,000074: 32,3036           02027                                    TBUP                                  #  LOAD TBUP*2(-17)
039735,000075: 32,3037           43342                           SR1      DAD                                   #  1/2 OLD TBUP*2(-17)
039736,000076: 32,3040           77625                           DSU                                            
039737,000077: 32,3041           25053                                    6SEC(18)                              #  GET NEW TBUP *2(-17)
039738,000078: 32,3042           16027                           STODL    TBUP                                  
039739,000079: 32,3043           02025                                    VE                                    
039740,000080: 32,3044           56342                           SR1      DDV                                   #  VE*2(-8)
039741,000081: 32,3045           02027                                    TBUP                                  #  AT*2(9)
039742,000082: 32,3046           02023                           STORE    AT                                    
039743,000083: 32,3047           77650        FILTEND            GOTO                                           
039744,000084: 32,3050           64125                                    ASCENT                                
039745,000085: 
039746,000086: 32,3051           00010        BIT4H              OCT      10                                    
039747,000087: 32,3052           00045 20000  6SEC(18)           2DEC     600        B-28                       
039748,000088: 
039749,000089: 32,3054           25715        ASCPATCH           STOVL    UNNORM                                #  PATCH FROM ASCENT STEERING LOG SECTION.
039750,000090: 32,3055           02340                                    RCOV                                  
039751,000091: 32,3056           52056                           UNIT     GOTO                                  
039752,000092: 32,3057           64327                                    ENDPATCH                              

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