/soy/ - Soyjaks

# Copyright:Public domain.
# Filename:THE_LUNAR_LANDING.agc
# Purpose: Part of the source code for Luminary 1A build 099.
#It is part of the source code for the Lunar Module's (LM)
#Apollo Guidance Computer (AGC), for Apollo 11.
# Assembler:yaYUL
# Contact:Hartmuth Gutsche<hgutsche@xplornet.com>.
# Website:www.ibiblio.org/apollo.
# Pages:785-792
# Mod history:2009-05-20 HGTranscribed from page images.
#
# This source code has been transcribed or otherwise adapted from
# digitized images of a hardcopy from the MIT Museum. The digitization
# was performed by Paul Fjeld, and arranged for by Deborah Douglas of
# the Museum. Many thanks to both. The images (with suitable reduction
# in storage size and consequent reduction in image quality as well) are
# available online at www.ibiblio.org/apollo. If for some reason you
# find that the images are illegible, contact me at info@sandroid.org
# about getting access to the (much) higher-quality images which Paul
# actually created.
#
# Notations on the hardcopy document read, in part:
#
#Assemble revision 001 of AGC program LMY99 by NASA 2021112-061
#16:27 JULY 14, 1969

# Page 785
BANK32
SETLOCF2DPS*32
BANK

EBANK=E2DPS

#*********
#P63: THE LUNAR LANDING, BRAKING PHASE
#*********

COUNT*$$/P63

P63LMTCPHASCHNG
OCT04024

TCBANKCALL# DO IMU STATUS CHECK ROUTINE R02
CADRR02BOTH

CAFP63ADRES# INITIALIZE WHICH FOR BURNBABY
TSWHICH

CAFDPSTHRSH# INITIALIZE DVMON
TSDVTHRUSH
CAFFOUR
TSDVCNTR

CSONE# INITIALIZE WCHPHASE AND FLPASS0
TSWCHPHASE

CAZERO
TSFLPASS0

CSBIT14
EXTEND
WANDCHAN12# REMOVE TRACK-ENABLE DISCRETE.

FLAGORGYTCINTPRET# DIONYSIAN FLAG WAVING
CLEARCLEAR
NOTHROTL
REDFLAG
CLEARSET
LRBYPASS
MUNFLAG
CLEARCLEAR
P25FLAG# TERMINATE P25 IF IT IS RUNNING.
RNDVZFLG# TERMINATE P20 IF IT IS RUNNING

# ********

IGNALGSETPDVLOAD# FIRST SET UP INPUTS FOR RP-TO-R:-
# Page 786
0# AT 0D LANDING SITE IN MOON FIXED FRAME
RLS# AT 6D ESTIMATED TIME OF LANDING
PDDLPUSH# MPAC NON-ZERO TO INDICATE LUNAR CASE
TLAND
STCALLTPIP# ALSO SET TPIP FOR FIRST GUIDANCE PASS
RP-TO-R
VSL4MXV
REFSMMAT
STCALLLAND
GUIDINIT# GUIDINIT INITIALIZES WM AND /LAND/
DLOADDSU
TLAND
GUIDDURN
STCALLTDEC1# INTEGRATE STATE FORWARD TO THAT TIME
LEMPREC
SSPVLOAD
NIGNLOOP
40D
UNITX
STOVLCG
UNITY
STOVLCG +6
UNITZ
STODLCG +14
99999CON
STOVLDELTAH# INITIALIZE DELTAH FOR V16N68 DISPLAY
ZEROVECS
STODLUNFC/2# INITIALIZE TRIM VELOCITY CORRECTION TERM
HI6ZEROS
STORETTF/8

IGNALOOPDLOAD
TAT
STOVLPIPTIME1
RATT1
VSL4MXV
REFSMMAT
STCALLR
MUNGRAV
STCALLGDT/2
?GUIDSUB# WHICH DELIVERS N PASSES OF GUIDANCE

# DDUMCALC IS PROGRAMMED AS FOLLOWS:-
# 2 ___
# (RIGNZ - RGU )/16 + 16(RGU )KIGNY/B8 + (RGU - RIGNX)KIGNX/B4 + (ABVAL(VGU) - VIGN)KIGNV/B4
# 2 1 0
#DDUM = -------------------
# 10
# 2 (VGU - 16 VGU KIGNX/B4)
# 2 0
# Page 787 new page is actually one line earlier but this would put the indices on a separate line
# disconnected from their respective variables
# THE NUMERATOR IS SCALED IN METERS AT 2(28). THE DENOMINATOR IS A VELOCITY IN UNITS OF 2(10) M/CS.
# THE QUOTIENT IS THUS A TIME IN UNITS OF 2(18) CENTISECONDS. THE FINAL SHIFT RESCALES TO UNITS OF 2(28) CS.
# THERE IS NO DAMPING FACTOR. THE CONSTANTS KIGNX/B4, KIGNY/B8 AND KIGNV/B4 ARE ALL NEGATIVE IN SIGN.

DDUMCALCTSNIGNLOOP
TCINTPRET
DLOADDMPR# FORM DENOMINATOR FIRST
VGU
KIGNX/B4
SL4RBDSU
VGU +4
PDDLDSU
RIGNZ
RGU +4
SR4RPDDL
RGU +2
DSQDMPR
KIGNY/B8
SL4RPDDL
RGU
DSUDMPR
RIGNX
KIGNX/B4
PDVLABVAL
VGU
DSUDMPR
VIGN
KIGNV/B4
DADDAD
DADDDV
SRR
10D

PUSHDAD
PIPTIME1
STODLTDEC1# STORE NEW GUESS FOR NEXT INTEGRATION
ABSDSU
DDUMCRIT
BMNCALL
DDUMGOOD
INTSTALL
SETSET
INTYPFLG
MOONFLAG
DLOAD
PIPTIME1
STOVLTET# HOPEFULLY ?GUIDSUB DID NOT
RATT1# CLOBBER RATT1 AND VATT1
# Page 788