336 lines
7.3 KiB
ArmAsm
336 lines
7.3 KiB
ArmAsm
# Copyright: Public domain.
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# Filename: THE_LUNAR_LANDING.agc
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# Purpose: Part of the source code for Luminary 1A build 099.
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# It is part of the source code for the Lunar Module's (LM)
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# Apollo Guidance Computer (AGC), for Apollo 11.
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# Assembler: yaYUL
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# Contact: Hartmuth Gutsche<hgutsche@xplornet.com>.
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# Website: www.ibiblio.org/apollo.
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# Pages: 785-792
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# Mod history: 2009-05-20 HG Transcribed from page images.
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#
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# This source code has been transcribed or otherwise adapted from
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# digitized images of a hardcopy from the MIT Museum. The digitization
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# was performed by Paul Fjeld, and arranged for by Deborah Douglas of
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# the Museum. Many thanks to both. The images (with suitable reduction
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# in storage size and consequent reduction in image quality as well) are
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# available online at www.ibiblio.org/apollo. If for some reason you
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# find that the images are illegible, contact me at info@sandroid.org
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# about getting access to the (much) higher-quality images which Paul
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# actually created.
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#
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# Notations on the hardcopy document read, in part:
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#
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# Assemble revision 001 of AGC program LMY99 by NASA 2021112-61
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# 16:27 JULY 14, 1969
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# Page 785
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BANK 32
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SETLOC F2DPS*32
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BANK
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EBANK= E2DPS
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# *************************************
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# P63: THE LUNAR LANDING, BRAKING PHASE
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# *************************************
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COUNT* $$/P63
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P63LM TC PHASCHNG
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OCT 04024
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TC BANKCALL # DO IMU STATUS CHECK ROUTINE R02
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CADR R02BOTH
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CAF P63ADRES # INITIALIZE WHICH FOR BURNBABY
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TS WHICH
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CAF DPSTHRSH # INITIALIZE DVMON
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TS DVTHRUSH
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CAF FOUR
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TS DVCNTR
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CS ONE # INITIALIZE WCHPHASE AND FLPASS0
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TS WCHPHASE
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CA ZERO
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TS FLPASS0
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CS BIT14
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EXTEND
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WAND CHAN12 # REMOVE TRACK-ENABLE DISCRETE.
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FLAGORGY TC INTPRET # DIONYSIAN FLAG WAVING
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CLEAR CLEAR
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NOTHROTL
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REDFLAG
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CLEAR SET
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LRBYPASS
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MUNFLAG
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CLEAR CLEAR
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P25FLAG # TERMINATE P25 IF IT IS RUNNING.
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RNDVZFLG # TERMINATE P20 IF IT IS RUNNING.
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# ********************************
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IGNALG SETPD VLOAD # FIRST SET UP INPUTS FOR RP-TO-R:
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# Page 786
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0 # AT 0D LANDING SITE IN MOON FIXED FRAME
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RLS # AT 6D ESTIMATED TIME OF LANDING
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PDDL PUSH # MPAC NON-ZERO TO INDICATE LUNAR CASE
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TLAND
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STCALL TPIP # ALSO SET TPIP FOR FIRST GUIDANCE PASS
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RP-TO-R
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VSL4 MXV
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REFSMMAT
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STCALL LAND
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GUIDINIT # GUIDINIT INITIALIZES WM AND /LAND/
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DLOAD DSU
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TLAND
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GUIDDURN
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STCALL TDEC1 # INTEGRATE STATE FORWARD TO THAT TIME
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LEMPREC
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SSP VLOAD
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NIGNLOOP
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40D
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UNITX
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STOVL CG
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UNITY
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STOVL CG +6
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UNITZ
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STODL CG +14
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99999CON
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STOVL DELTAH # INITIALIZE DELTAH FOR V16N68 DISPLAY
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ZEROVECS
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STODL UNFC/2 # INITIALIZE TRIM VELOCITY CORRECTION TERM
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HI6ZEROS
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STORE TTF/8
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IGNALOOP DLOAD
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TAT
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STOVL PIPTIME1
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RATT1
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VSL4 MXV
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REFSMMAT
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STCALL R
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MUNGRAV
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STCALL GDT/2
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?GUIDSUB # WHICH DELIVERS N PASSES OF GUIDANCE
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# DDUMCALC IS PROGRAMMED AS FOLLOWS:
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# 2 ___
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# (RIGNZ - RGU )/16 + 16(RGU )KIGNY/B8 + (RGU - RIGNX)KIGNX/B4 + (ABVAL(VGU) - VIGN)KIGNV/B4
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# 2 1 0
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# DDUM = -------------------------------------------------------------------------------------------
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# 10
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# 2 (VGU - 16 VGU KIGNX/B4)
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# 2 0
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# Page 787 new page is actually one line earlier but this would put the indices on a seperate line
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# disconnected from their respective variables
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# THE NUMERATOR IS SCALED IN METERS AT 2(28). THE DENOMINATOR IS A VELOCITY IN UNITS OF 2(10) M/CS.
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# THE QUOTIENT IS THUS A TIME IN UNITS OF 2(18) CENTISECONDS. THE FINAL SHIFT RESCALES TO UNITS OF 2(28) CS.
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# THERE IS NO DAMPING FACTOR. THE CONSTANTS KIGNX/B4, KIGNY/B8 AND KIGNV/B4 ARE ALL NEGATIVE IN SIGN.
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DDUMCALC TS NIGNLOOP
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TC INTPRET
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DLOAD DMPR # FORM DENOMINATOR FIRST
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VGU
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KIGNX/B4
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SL4R BDSU
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VGU +4
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PDDL DSU
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RIGNZ
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RGU +4
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SR4R PDDL
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RGU +2
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DSQ DMPR
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KIGNY/B8
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SL4R PDDL
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RGU
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DSU DMPR
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RIGNX
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KIGNX/B4
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PDVL ABVAL
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VGU
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DSU DMPR
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VIGN
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KIGNV/B4
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DAD DAD
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DAD DDV
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SRR
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10D
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PUSH DAD
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PIPTIME1
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STODL TDEC1 # STORE NEW GUESS FOR NEXT INTEGRATION
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ABS DSU
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DDUMCRIT
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BMN CALL
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DDUMGOOD
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INTSTALL
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SET SET
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INTYPFLG
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MOONFLAG
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DLOAD
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PIPTIME1
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STOVL TET # HOPEFULLY ?GUIDSUB DID NOT
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RATT1 # CLOBBER RATT1 AND VATT1
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# Page 788
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STOVL RCV
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VATT1
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STCALL VCV
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INTEGRVS
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GOTO
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IGNALOOP
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DDUMGOOD SLOAD SR
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ZOOMTIME
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14D
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BDSU
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TDEC1
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STOVL TIG # COMPUTE DISTANCE LANDING SITE WILL BE
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V # OUT OF LM'S ORBITAL PLANE AT IGNITION:
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VXV UNIT # SIGN IS + IF LANDING SITE IS TO THE
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R # RIGHT, NORTH; - IF TO THE LEFT, SOUTH.
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DOT SL1
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LAND
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R60INIT STOVL OUTOFPLN # INITIALIZATION FOR CALCMANU
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UNFC/2
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STORE R60VSAVE # STORE UNFC/2 TEMPORARILY IN R60SAVE
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EXIT
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# *******************************************
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IGNALGRT TC PHASCHNG # PREVENT REPEATING IGNALG
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OCT 04024
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ASTNCLOK CS ASTNDEX
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TC BANKCALL
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CADR STCLOK2
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TCF ENDOFJOB # RETURN IN NEW JOB AND IN EBANK FIVE
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ASTNRET TC INTPRET
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SSP RTB # GO PICK UP DISPLAY AT END OF R51:
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QMAJ # "PROCEED" WILL DO A FINE ALIGNMENT
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FCADR P63SPOT2 # "ENTER" WILL RETURN TO P63SPOT2
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R51P63
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P63SPOT2 VLOAD UNIT # INITIALIZE KALCMANU FOR BURN ATTITUDE
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R60VSAVE
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STOVL POINTVSM
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UNITX
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STORE SCAXIS
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EXIT
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CAF EBANK7
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TS EBANK
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INHINT
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TC IBNKCALL
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CADR PFLITEDB
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# Page 789
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RELINT
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TC BANKCALL
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CADR R60LEM
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TC PHASCHNG # PREVENT RECALLING R60
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OCT 04024
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P63SPOT3 CA BIT6 # IS THE LR ANTENNA IN POSITION 1 YET
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EXTEND
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RAND CHAN33
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EXTEND
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BZF P63SPOT4 # BRANCH IF ANTENNA ALREADY IN POSITION 1
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CAF CODE500 # ASTRONAUT: PLEASE CRANK THE
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TC BANKCALL # SILLY THING AROUND
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CADR GOPERF1
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TCF GOTOP00H # TERMINATE
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TCF P63SPOT3 # PROCEED SEE IF HE'S LYING
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P63SPOT4 TC BANKCALL # ENTER INITIALIZE LANDING RADAR
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CADR SETPOS1
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TC POSTJUMP # OFF TO SEE THE WIZARD ...
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CADR BURNBABY
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# ---------------------------------
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# CONSTANTS FOR P63LM AND IGNALG
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P63ADRES GENADR P63TABLE
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ASTNDEX = MD1 # OCT 25: INDEX FOR CLOKTASK
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CODE500 OCT 00500
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99999CON 2DEC 30479.7 B-24
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GUIDDURN 2DEC +66440 # GUIDDURN +6.64400314 E+2
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DDUMCRIT 2DEC +8 B-28 # CRITERION FOR IGNALG CONVERGENCE
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# Page 790
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# --------------------------------
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# Page 791
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# *************************
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# P68: LANDING CONFIRMATION
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# *************************
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BANK 31
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SETLOC F2DPS*31
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BANK
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COUNT* $$/P6567
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LANDJUNK TC PHASCHNG
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OCT 04024
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INHINT
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TC BANKCALL # ZERO ATTITUDE ERROR
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CADR ZATTEROR
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TC BANKCALL # SET 5 DEGREE DEADBAND
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CADR SETMAXDB
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TC INTPRET # TO INTERPRETIVE AS TIME IS NOT CRITICAL
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SET CLEAR
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SURFFLAG
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LETABORT
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SET VLOAD
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APSFLAG
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RN
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STODL ALPHAV
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PIPTIME
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SET CALL
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LUNAFLAG
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LAT-LONG
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SETPD VLOAD # COMPUTE RLS AND STORE IT AWAY
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0
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RN
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VSL2 PDDL
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PIPTIME
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PUSH CALL
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R-TO-RP
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STORE RLS
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EXIT
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CAF V06N43* # ASTRONAUT: NOW LOOK WHERE TO ENDED UP
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TC BANKCALL
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CADR GOFLASH
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TCF GOTOP00H # TERMINATE
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TCF +2 # PROCEED
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TCF -5 # RECYCLE
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TC INTPRET
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# Page 792
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VLOAD # INITIALIZE GSAV AND (USING REFMF)
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UNITX # YNBSAV, ZNBSAV AND ATTFLAG FOR P57
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STCALL GSAV
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REFMF
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EXIT
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TCF GOTOP00H # ASTRONAUT: PLEASE SELECT P57
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V06N43* VN 0643
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