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# Copyright: Public domain.
# Filename: LUNAR_LANDING_GUIDANCE_EQUATIONS.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: 798-828
# Mod history: 2009-05-23 HG Transcribed from page images.
# 2009-06-05 RSB Fixed a goofy thing that was apparently
# legal in GAP but not in yaYUL. Eliminated
# a couple of lines of code that shouldn't
# have survived from Luminary 131 to here.
# 2009-06-07 RSB Fixed a typo.
#
# 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 2021112-61
# 16:27 JULY 14, 1969
# Page 798
EBANK= E2DPS
COUNT* $$/F2DPS
# ********************************************************
# LUNAR LANDING FLIGHT SEQUENCE TABLES
# ********************************************************
# FLIGHT SEQUENCE TABLES ARE ARRANGED BY FUNCTION. THEY ARE REFERENCED USING AS AN INDEX THE REGISTER WCHPHASE:
# WCHPHASE = -1 ---> IGNALG
# WCHPHASE = 0 ---> BRAKQUAD
# WCHPHASE = 1 ---> APPRQUAD
# WCHPHASE = 2 ---> VERTICAL
#*********************************************************
# ROUTINES FOR STARTING NEW GUIDANCE PHASES:
TCF TTFINCR # IGNALG
NEWPHASE TCF TTFINCR # BRAKQUAD
TCF STARTP64 # APPRQUAD
TCF P65START # VERTICAL
# PRE-GUIDANCE COMPUTATIONS:
TCF CALCRGVG # IGNALG
PREGUIDE TCF RGVGCALC # BRAKQUAD
TCF REDESIG # APPRQUAD
TCF RGVGCALC # VERTICAL
# GUIDANCE EQUATIONS:
TCF TTF/8CL # IGNALG
WHATGUID TCF TTF/8CL # BRAKQUAD
TCF TTF/8CL # APPRQUAD
TCF VERTGUID # VERTICAL
# POST GUIDANCE EQUATION COMPUTATIONS:
TCF CGCALC # IGNALG
AFTRGUID TCF CGCALC # BRAKQUAD
TCF CGCALC # APPRQUAD
TCF STEER? # VERTICAL
# Page 799
# WINDOW VECTOR COMPUTATIONS:
TCF EXGSUB # IGNALG
WHATEXIT TCF EXBRAK # BRAKQUAD
TCF EXNORM # APPRQUAD
# DISPLAY ROUTINES:
WHATDISP TCF P63DISPS # BRAKQUAD
TCF P64DISPS # APPRQUAD
TCF VERTDISP # VERTICAL
# ALARM ROUTINE FOR TTF COMPUTATION:
TCF 1406P00 # IGNALG
WHATALM TCF 1406ALM # BRAKQUAD
TCF 1406ALM # APPRQUAD
# INDICES FOR REFERENCING TARGET PARAMETERS
OCT 0 # IGNALG
TARGTDEX OCT 0 # BRAKQUAD
OCT 34 # APPRQUAD
#************************************************************************
# ENTRY POINTS: ?GUIDSUB FOR THE IGNITION ALGORITHM, LUNLAND FOR SERVOUT
#************************************************************************
# IGNITION ALGORITHM ENTRY: DELIVERS N PASSES OF QUADRATIC GUIDANCE
?GUIDSUB EXIT
CAF TWO # N = 3
TS NGUIDSUB
TCF GUILDRET +2
GUIDSUB TS NGUIDSUB # ON SUCCEEDING PASSES SKIP TTFINCR
TCF CALCRGVG
# NORMAL ENTRY: CONTROL COMES HERE FROM SERVOUT
LUNLAND TC PHASCHNG
OCT 00035 # GROUP 5: RETAIN ONLY PIPA TASK
TC PHASCHNG
OCT 05023 # GROUP 3: PROTECT GUIDANCE WITH PRIO 21
OCT 21000 # JUST HIGHER THAN SERVICER'S PRIORITY
# Page 800
#*******************************************************************
# GUILDENSTERN: AUTO-MODES MONITOR (R13)
#*******************************************************************
COUNT* $$/R13
# HERE IS THE PHILOSOPHY OF GUILDENSTERN: ON EVERY APPEARANCE OR DISAPPEARANCE OF THE MANUAL THROTTLE
# DISCRETE TO SELECT P67 OR P66 RESPECTIVELY: ON EVERY APPEARANCE OF THE ATTITUDE-HOLD DISCRETE TO SELECT P66
# UNLESS THE CURRENT PROGRAM IS P67 IN WHICH CASE THERE IS NO CHANGE
GUILDEN EXTEND # IS UN-AUTO-THROTTLE DISCRETE PRESENT?
# STERN # RSB 2009: Not originally a comment.
READ CHAN30
MASK BIT5
CCS A
TCF STARTP67 # YES
P67NOW? TC CHECKMM # NO: ARE WE IN P67 NOW?
DEC 67
TCF STABL? # NO
STARTP66 TC FASTCHNG # YES
TC NEWMODEX
DEC66 DEC 66
EXTEND
DCA HDOTDISP # SET DESIRED ALTITUDE RATE = CURRENT
DXCH VDGVERT # ALTITUDE RATE.
STRTP66A TC INTPRET
SLOAD PUSH
PBIASZ
SLOAD PUSH
PBIASY
SLOAD VDEF
PBIASX
VXSC SET
BIASFACT
RODFLAG
STOVL VBIAS
TEMX
VCOMP
STOVL OLDPIPAX
ZEROVECS
STODL DELVROD
RODSCALE
STODL RODSCAL1
PIPTIME
STORE LASTTPIP
EXIT
CAF ZERO
TS FCOLD
TS FWEIGHT
TS FWEIGHT +1
VRTSTART TS WCHVERT
# Page 801
CAF TWO # WCHPHASE = 2 ---> VERTICAL: P65,P66,P67
TS WCHPHOLD
TS WCHPHASE
TC BANKCALL # TEMPORARY, I HOPE HOPE HOPE
CADR STOPRATE # TEMPORARY, I HOPE HOPE HOPE
TC DOWNFLAG # PERMIT X-AXIS OVERRIDE
ADRES XOVINFLG
TC DOWNFLAG
ADRES REDFLAG
TCF VERTGUID
STARTP67 TC NEWMODEX # NO HARM IN "STARTING" P67 OVER AND OVER
DEC 67 # SO NO NEED FOR A FASTCHNG AND NO NEED
CAF ZERO # TO SEE IF ALREADY IN P67.
TS RODCOUNT
CAF TEN
TCF VRTSTART
STABL? CAF BIT13 # IS UN-ATTITUDE-HOLD DISCRETE PRESENT?
EXTEND
RAND CHAN31
CCS A
TCF GUILDRET # YES ALL'S WELL
P66NOW? CS MODREG
AD DEC66
EXTEND
BZF RESTART?
CA RODCOUNT # NO. HAS THE ROD SWITCH BEEN "CLICKED"?
EXTEND
BZF GUILDRET # NO. CONTINUE WITH AUTOMATIC LANDING
TCF STARTP66 # YES. SWITCH INTO THE ROD MODE.
RESTART? CA FLAGWRD1 # HAS THERE BEEN A RESTART?
MASK RODFLBIT
EXTEND
BZF STRTP66A # YES. REINITIALIZE BUT LEAVE VDGVERT AS
# IS.
TCF VERTGUID # NO: CONTINUE WITH R.O.D.
# *******************************************************************************
# INITIALIZATION FOR THIS PASS
# *******************************************************************************
COUNT* $$/F2DPS
GUILDRET CAF ZERO
TS RODCOUNT
# Page 802
+2 EXTEND
DCA TPIP
DXCH TPIPOLD
TC FASTCHNG
EXTEND
DCA PIPTIME1
DXCH TPIP
EXTEND
DCA TTF/8
DXCH TTF/8TMP
CCS FLPASS0
TCF TTFINCR
BRSPOT1 INDEX WCHPHASE
TCF NEWPHASE
# ******************************************************************
# ROUTINES TO START NEW PHASES
# ******************************************************************
P65START TC NEWMODEX
DEC 65
CS TWO
TS WCHVERT
TC DOWNFLAG # PERMIT X-AXIS OVERRIDE
ADRES XOVINFLG
TCF TTFINCR
STARTP64 TC NEWMODEX
DEC 64
CA DELTTFAP # AUGMENT TTF/8
ADS TTF/8TMP
CA BIT12 # ENABLE RUPT10
EXTEND
WOR CHAN13
TC DOWNFLAG # INITIALIZE REDESIGNATION FLAG
ADRES REDFLAG
# (CONTINUE TO TTFINCR)
# *********************************************************************************
# INCREMENT TTF/8, UPDATE LAND FOR LUNAR ROTATION, DO OTHER USEFUL THINGS
# *********************************************************************************
#
# TTFINCR COMPUTATIONS ARE AS FOLLOWS --
# Page 803
# TTF/8 UPDATED FOR TIME SINCE LAST PASS:
# TTF/8 = TTF/8 + (TPIP - TPIPOLD)/8
# LANDING SITE VECTOR UPDATED FOR LUNAR ROTATION:
# ____ ____ ____ __
# LAND = /LAND/ UNIT(LAND - LAND(TPIP - TPIPOLD) * WM)
# SLANT RANGE TO LANDING SITE, FOR DISPLAY:
# ____ _
# RANGEDSP = ABVAL(LAND - R)
TTFINCR TC INTPRET
DLOAD DSU
TPIP
TPIPOLD
SLR PUSH # SHIFT SCALES DELTA TIME TO 2(17) CSECS
11D
VXSC VXV
LAND
WM
BVSU RTB
LAND
NORMUNIT
VXSC VSL1
/LAND/
STODL LANDTEMP
EXIT
DXCH MPAC
DAS TTF/8TMP # NOW HAVE INCREMENTED TTF/8 IN TTF/8TMP
TC FASTCHNG
EXTEND
DCA TTF/8TMP
DXCH TTF/8
EXTEND
DCA LANDTEMP
DXCH LAND
EXTEND
DCA LANDTEMP +2
DXCH LAND +2
EXTEND
DCA LANDTEMP +4
DXCH LAND +4
# Page 804
TC TDISPSET
TC FASTCHNG # SINCE REDESIG MAY CHANGE LANDTEMP
BRSPOT2 INDEX WCHPHASE
TCF PREGUIDE
# *********************************************************************
# LANDING SITE PERTURBATION EQUATIONS
# *********************************************************************
REDESIG CA FLAGWRD6 # IS REDFLAG SET?
MASK REDFLBIT
EXTEND
BZF RGVGCALC # NO: SKIP REDESIGNATION LOGIC
CA TREDES # YES: HAS TREDES REACHED ZERO?
EXTEND
BZF RGVGCALC # YES: SKIP REDESIGNATION LOGIC
INHINT
CA ELINCR1
TS ELINCR
CA AZINCR1
TS AZINCR
TC FASTCHNG
CA ZERO
TS ELINCR1
TS AZINCR1
TS ELINCR +1
TS AZINCR +1
CA FIXLOC # SET PD TO 0
TS PUSHLOC
TC INTPRET
VLOAD VSU
LAND
R # ____ _
RTB PUSH # PUSH DOWN UNIT (LAND - R)
NORMUNIT
VXV VSL1
YNBPIP # ___ ____ _
VXSC PDDL # PUSH DOWN - ELINCR(YNB * UNIT(LAND - R))
ELINCR
AZINCR
VXSC VSU
YNBPIP
VAD PUSH # RESULTING VECTOR IS 1/2 REAL SIZE
# Page 805
DLOAD DSU # MAKE SURE REDESIGNATION IS NOT
0 # TOO CLOSE TO THE HORIZON.
DEPRCRIT
BMN DLOAD
REDES1
DEPRCRIT
STORE 0
REDES1 DLOAD DSU
LAND
R
DDV VXSC
0
VAD UNIT
R
VXSC VSL1
/LAND/
STORE LANDTEMP
EXIT # LOOKANGL WILL BE COMPUTED AT RGVGCALC
TC FASTCHNG
EXTEND
DCA LANDTEMP
DXCH LAND
EXTEND
DCA LANDTEMP +2
DXCH LAND +2
EXTEND
DCA LANDTEMP +4
DXCH LAND +4
TCF RGVGCALC
# *********************************************************************
# COMPUTE STATE IN GUIDANCE COORDINATES
# *********************************************************************
#
# RGVGCALC COMPUTATIONS ARE AS FOLLOWS:--
# VELOCITY RELATIVE TO THE SURFACE:
# _______ _ _ __
# ANGTERM = V + R * WM
# STATE IN GUIDANCE COORDINATES:
# ___ * _ ____
# RGU = CG (R - LAND)
# ___ * _ __ _
# VGU = CG (V - WM * R)
# Page 806 actually starts one line earlier but that would separate the markers from their variables
#
# HORIZONTAL VELOCITY FOR DISPLAY
#
# VHORIZ = 8 ABVAL (0, VG , VG )
# 2 1
# DEPRESSION ANGLE FOR DISPLAY:
# _ ____ ______
# LOOKANGL = ARCSIN(UNIT(R - LAND).XMBPIP)
CALCRGVG TC INTPRET # IN IGNALG, COMPUTE V FROM INTEGRATION
VLOAD MXV # OUTPUT AND TRIM CORRECTION TERM
VATT1 # COMPUTED LAST PASS AND LEFT IN UNFC/2
REFSMMAT
VSR1 VAD
UNFC/2
STORE V
EXIT
RGVGCALC TC INTPRET # ENTER HERE TO RECOMPUTE RG AND VG
VLOAD VXV
R
WM
VAD VSR2 # RESCALE TO UNITS OF 2(9) M/CS
V
STORE ANGTERM
MXV
CG # NO SHIFT SINCE ANGTERM IS DOUBLE SIZED
STORE VGU
PDDL VDEF # FORM (0,VG ,VG ) IN UNITS OF 2(10) M/CS
ZEROVECS # 2 1
ABVAL SL3
STOVL VHORIZ # VHORIZ FOR DISPLAY DURING P65.
R # _ ____
VSU PUSH # PUSH DOWN R - LAND
LAND
MXV VSL1
CG
STORE RGU
ABVAL
STOVL RANGEDSP
RTB DOT # NOW IN MPAC IS SINE(LOOKANGL)/4
NORMUNIT
XNBPIP
EXIT
CA FIXLOC # RESET PUSH DOWN POINTER
TS PUSHLOC
# Page 807
CA MPAC # COMPUTE LOOKANGLE ITSELF
DOUBLE
TC BANKCALL
CADR SPARCSIN -1
AD 1/2DEG
EXTEND
MP 180DEGS
TS LOOKANGL # LOOKANGL FOR DISPLAY DURING P64
BRSPOT3 INDEX WCHPHASE
TCF WHATGUID
# **************************************************************************
# TTF/8 COMPUTATION
# **************************************************************************
TTF/8CL TC INTPRETX
DLOAD*
JDG2TTF,1
STODL* TABLTTF +6 # A(3) = 8 JDG TO TABLTTF
ADG2TTF,1 # 2
STODL TABLTTF +4 # A(2) = 6 ADG TO TABLTTF
VGU +4 # 2
DMP DAD*
3/4DP
VDG2TTF,1
STODL* TABLTTF +2 # A(1) = (6 VGU + 18 VDG )/8 TO TABLTTF
RDG +4,1 # 2 2
DSU DMP
RGU +4
3/8DP
STORE TABLTTF # A(0) = -24 (RGU - RDG )/64 TO TABLTTF
EXIT # 2 2
CA BIT8
TS TABLTTF +10 # FRACTIONAL PRECISION FOR TTF TO TABLE
EXTEND
DCA TTF/8
DXCH MPAC # LOADS TTF/8 (INITIAL GUESS) INTO MPAC
CAF TWO # DEGREE - ONE
TS L
CAF TABLTTFL
TC ROOTPSRS # YIELDS TTF/8 IN MPAC
INDEX WCHPHASE
TCF WHATALM
EXTEND # GOOD RETURN
DCA MPAC # FETCH TTF/8 KEEPING IT IN MPAC
DXCH TTF/8 # CORRECTED TTF/8
# Page 808
TC TDISPSET
# (CONTINUE TO QUADGUID)
# *********************************************************************************
# MAIN GUIDANCE EQUATION
# *********************************************************************************
#
# AS PUBLISHED --
# ___ __ ___ __
# ___ ___ 6(VDG + VG) 12(RDG - RG)
# ACG = ADG + ----------- + ------------
# TTF (TTF)(TTF)
# AS HERE PROGRAMMED --
# ___ __
# 3 (1/4(RDG - RG) ___ __)
# - (------------- + VDG + VG)
# ___ 4 ( TTF/8 ) ___
# ACG = ---------------------------- + ADG
# TTF/8
QUADGUID CS TTF/8
AD LEADTIME # LEADTIME IS A NEGATIVE NUMBER
AD POSMAX # SAFEGUARD THE COMPUTATIONS THAT FOLLOW
TS L # BY FORCING -TTF*LEADTIME > OR = ZERO
CS L
AD L
ZL
EXTEND
DV TTF/8
TS BUF # - RATIO OF LAG-DIMINISHED TTF TO TTF
EXTEND
SQUARE
TS BUF +1
AD BUF
XCH BUF +1 # RATIO SQUARED - RATIO
AD BUF +1
TS MPAC # COEFFICIENT FOR VGU TERM
AD BUF +1
INDEX FIXLOC
TS 26D # COEFFICIENT FOR RDG-RGU TERM
AD BUF +1
INDEX FIXLOC
TS 28D # COEFFICIENT FOR VDG TERM
AD BUF
AD POSMAX
# Page 809
AD BUF +1
AD BUF +1
INDEX FIXLOC
TS 30D # COEFFICIENT FOR ADG TERM
CAF ZERO
TS MODE
TC INTPRETX
VXSC PDDL
VGU
28D
VXSC* PDVL*
VDG,1
RDG,1
VSU V/SC
RGU
TTF/8
VSR2 VXSC
26D
VAD VAD
V/SC VXSC
TTF/8
3/4DP
PDDL VXSC*
30D
ADG,1
VAD
AFCCALC1 VXM VSL1 # VERGUID COMES HERE
CG
PDVL V/SC
GDT/2
GSCALE
BVSU STADR
STORE UNFC/2 # UNFC/2 NEED NOT BE UNITIZED
ABVAL
AFCCALC2 STODL /AFC/ # MAGNITUDE OF AFC FOR THROTTLE
UNFC/2 # VERTICAL COMPONENT
DSQ PDDL
UNFC/2 +2 # OUT-OF-PLANE
DSQ PDDL
HIGHESTF
DDV DSQ
MASS # 2 2 2
DSU DSU # AMAXHORIZ = SQRT(ATOTAL - A - A )
BPL DLOAD # 1 0
AFCCALC3
ZEROVECS
AFCCALC3 SQRT DAD
UNFC/2 +4
# Page 810
BPL BDSU
AFCCLEND
UNFC/2 +4
STORE UNFC/2 +4
AFCCLEND EXIT
TC FASTCHNG
CA WCHPHASE # PREPARE FOR PHASE SWITCHING LOGIC
TS WCHPHOLD
INCR FLPASS0 # INCREMENT PASS COUNTER
BRSPOT4 INDEX WCHPHASE
TCF AFTRGUID
# ***********************************************************************
# ERECT GUIDANCE-STABLE MEMBER TRANSFORMATION MATRIX
# ***********************************************************************
CGCALC CAF EBANK5
TS EBANK
EBANK= TCGIBRAK
EXTEND
INDEX WCHPHASE
INDEX TARGTDEX
DCA TCGFBRAK
INCR BBANK
INCR BBANK
EBANK= TTF/8
AD TTF/8
XCH L
AD TTF/8
CCS A
CCS L
TCF EXTLOGIC
TCF EXTLOGIC
NOOP
TC INTPRETX
VLOAD UNIT
LAND
STODL CG
TTF/8
DMP* VXSC
GAINBRAK,1 # NUMERO MYSTERIOSO
ANGTERM
VAD
LAND
VSU RTB
R
NORMUNIT
# Page 811
VXV RTB
LAND
NORMUNIT
STOVL CG +6 # SECOND ROW
CG
VXV VSL1
CG +6
STORE CG +14
EXIT
# (CONTINUE TO EXTLOGIC)
#
# ***********************************************************************
# PREPARE TO EXIT
# ***********************************************************************
#
# DECIDE (1) HOW TO EXIT, AND (2) WHETHER TO SWITCH PHASES
#
EXTLOGIC INDEX WCHPHASE # WCHPHASE = 1 APPRQUAD
CA TENDBRAK # WCHPHASE = 0 BRAKQUAD
AD TTF/8
EXSPOT1 EXTEND
INDEX WCHPHASE
BZMF WHATEXIT
TC FASTCHNG
CA WCHPHOLD
AD ONE
TS WCHPHASE
CA ZERO
TS FLPASS0 # RESET FLPASS0
INDEX WCHPHOLD
TCF WHATEXIT
# ***********************************************************************
# ROUTINES FOR EXITING FROM LANDING GUIDANCE
# ***********************************************************************
#
# 1. EXGSUB IS THE RETURN WHEN GUIDSUB IS CALLED BY THE IGNITION ALGORITHM.
# 2. EXBRAK IN THE EXIT USED DURING THE BRAKING PHASE. IN THIS CASE UNIT(R) IS THE WINDOW POINTING VECTOR.
# 3. EXNORM IS THE EXIT USED AT OTHER TIMES DURING THE BURN.
# (EXOVFLOW IS A SUBROUTINE OF EXBRAK AND EXNORM CALLED WHEN OVERFLOW OCCURRED ANYWHERE IN GUIDANCE.)
EXGSUB TC INTPRET # COMPUTE TRIM VELOCITY CORRECTION TERM.
# Page 812
VLOAD RTB
UNFC/2
NORMUNIT
VXSC VXSC
ZOOMTIME
TRIMACCL
STORE UNFC/2
EXIT
CCS NGUIDSUB
TCF GUIDSUB
CCS NIGNLOOP
TCF +3
TC ALARM
OCT 01412
+3 TC POSTJUMP
CADR DDUMCALC
EXBRAK TC INTPRET
VLOAD
UNIT/R/
STORE UNWC/2
EXIT
TCF STEER?
EXNORM TC INTPRET
VLOAD VSU
LAND
R
RTB
NORMUNIT
STORE UNWC/2 # UNIT(LAND - R) IS TENTATIVE CHOICE
VXV DOT
XNBPIP
CG +6
EXIT # WITH PROJ IN MPAC 1/8 REAL SIZE
CS MPAC # GET COEFFICIENT FOR CG +14
AD PROJMAX
AD POSMAX
TS BUF
CS BUF
ADS BUF # RESULT IS 0 IF PROJMAX - PROJ NEGATIVE
CS PROJMIN # GET COEFFICIENT FOR UNIT(LAND - R)
AD MPAC
AD POSMAX
TS BUF +1
CS BUF +1
# Page 813
ADS BUF +1 # RESULT IS 0 IF PROJ - PROJMIN NEGATIVE
CAF FOUR
UNWCLOOP MASK SIX
TS Q
CA EBANK5
TS EBANK
EBANK= CG
CA BUF
EXTEND
INDEX Q
MP CG +14
INCR BBANK
EBANK= UNWC/2
INDEX Q
DXCH UNWC/2
EXTEND
MP BUF +1
INDEX Q
DAS UNWC/2
CCS Q
TCF UNWCLOOP
INCR BBANK
EBANK= PIF
STEER? CA FLAGWRD2 # IF STEERSW DOWN NO OUTPUTS
MASK STEERBIT
EXTEND
BZF RATESTOP
EXVERT CA OVFIND # IF OVERFLOW ANYWHERE IN GUIDANCE
EXTEND # DON'T CALL THROTTLE OR FINDCDUW
BZF +13
EXOVFLOW TC ALARM # SOUND THE ALARM NON-ABORTIVELY
OCT 01410
RATESTOP CAF BIT13 # ARE WE IN ATTITUDE-HOLD?
EXTEND
RAND CHAN31
EXTEND
BZF DISPEXIT # YES
TC BANKCALL # NO: DO A STOPRATE
CADR STOPRATE
TCF DISPEXIT
GDUMP1 TC THROTTLE
# Page 814
TC INTPRET
CALL
FINDCDUW -2
EXIT
# (CONTINUE TO DISPEXIT)
# ***********************************************************************
# GUIDANCE LOOP DISPLAYS
# ***********************************************************************
DISPEXIT EXTEND # KILL GROUP 3: DISPLAYS WILL BE
DCA NEG0 # RESTORED BY NEXT GUIDANCE CYCLE.
DXCH -PHASE3
+3 CS FLAGWRD8 # IF FLUNDISP IS SET, NO DISPLAY THIS PASS
MASK FLUNDBIT
EXTEND
BZF ENDLLJOB # TO PICK UP THE TAG
INDEX WCHPHOLD
TCF WHATDISP
-2 TC PHASCHNG # KILL GROUP 5
OCT 00035
P63DISPS CAF V06N63
DISPCOMN TC BANKCALL
CADR REGODSPR
ENDLLJOB TCF ENDOFJOB
P64DISPS CA TREDES # HAS TREDES REACHED ZERO?
EXTEND
BZF RED-OVER # YES: CLEAR REDESIGNATION FLAG
CS FLAGWRD6 # NO: IS REDFLAG SET?
MASK REDFLBIT
EXTEND
BZF REDES-OK # YES: DO STATIC DISPLAY
CAF V06N64 # OTHERWISE USE FLASHING DISPLAY
TC BANKCALL
CADR REFLASHR
TCF GOTOP00H # TERMINATE
TCF P64CEED # PROCEED PERMIT REDESIGNATIONS
TCF P64DISPS # RECYCLE
# Page 815
TCF ENDLLJOB
P64CEED CAF ZERO
TS ELINCR1
TS AZINCR1
TC UPFLAG # ENABLE REDESIGNATION LOGIC
ADRES REDFLAG
TCF ENDOFJOB
RED-OVER TC DOWNFLAG
ADRES REDFLAG
REDES-OK CAF V06N64
TCF DISPCOMN
VERTDISP CAF V06N60
TCF DISPCOMN
# **************************************************************************
# GUIDANCE FOR P65
# **************************************************************************
VERTGUID CCS WCHVERT
TCF P67VERT # POSITIVE NON-ZERO ---> P67
TCF P66VERT # +0
#
# THE P65 GUIDANCE EQUATION IS AS FOLLOWS --
# ____ ___
# V2FG - VGU
# ACG = ----------
# TAUVERT
P65VERT TC INTPRET
VLOAD VSU
V2FG
VGU
V/SC GOTO
TAUVERT
AFCCALC1
# Page 816
# **********************************************************
# GUIDANCE FOR P66
# **********************************************************
P66VERT TC POSTJUMP
CADR P66VERTA
P67VERT TC PHASCHNG # TERMINATE GROUP 3.
OCT 00003
TC INTPRET
VLOAD GOTO
V
VHORCOMP
SETLOC P66LOC
BANK
COUNT* $$/F2DPS
RODTASK CAF PRIO22
TC FINDVAC
EBANK= DVCNTR
2CADR RODCOMP
TCF TASKOVER
P66VERTA TC PHASCHNG # TERMINATE GROUP 3.
OCT 00003
CAF 1SEC
TC TWIDDLE
ADRES RODTASK
RODCOMP INHINT
CAF ZERO
XCH RODCOUNT
EXTEND
MP RODSCAL1
DAS VDGVERT # UPDATE DESIRED ALTITUDE RATE.
EXTEND # SET OLDPIPAX,Y,Z = PIPAX,Y,Z
DCA PIPAX
DXCH OLDPIPAX
DXCH RUPTREG1 # SET RUPTREG1,2,3 = OLDPIPAX,Y,Z
CA PIPAZ
XCH OLDPIPAZ
XCH RUPTREG3
EXTEND # SNAPSHOT TIME OF PIPA READING.
DCA TIME2
# Page 817
DXCH THISTPIP
CA OLDPIPAX
AD PIPATMPX
TS MPAC # MPAC(X) = PIPAX + PIPATMPX
CA OLDPIPAY
AD PIPATMPY
TS MPAC +3 # MPAC(Y) = PIPAY + PIPATMPY
CA OLDPIPAZ
AD PIPATMPZ
TS MPAC +5 # MPAC(Z) = PIPAZ + PIPATMPZ
CS OLDPIPAX
AD TEMX
AD RUPTREG1
TS DELVROD
CS OLDPIPAY
AD TEMY
AD RUPTREG2
TS DELVROD +2
CS OLDPIPAZ
AD TEMZ
AD RUPTREG3
TS DELVROD +4
CAF ZERO
TS MPAC +1 # ZERO LO-ORDER MPAC COMPONENTS
TS MPAC +4
TS MPAC +6
TS TEMX # ZERO TEMX, TEMY, AND TEMZ SO WE WILL
TS TEMY # KNOW WHEN READACCS CHANGES THEM.
TS TEMZ
CS ONE
TS MODE
TC INTPRET
ITRPNT1 VXSC PDDL # SCALE MPAC TO M/CS *2(-7) AND PUSH (6)
KPIP1
THISTPIP
DSU
PIPTIME
STORE 30D # 30-31D CONTAINS TIME IN CS SINCE PIPTIME
DDV PDVL # (8)
4SEC(28)
GDT/2
VSU VXSC # (6)
VBIAS
VSL2 VAD
V
VAD STADR # (0)
STOVL 24D # STORE UPDATED VELOCITY IN 24-29D
# Page 818
R
UNIT
STORE 14D
DOT SL1
24D
STODL HDOTDISP # UPDATE HDOTDISP RATE FOR NOUN 63.
30D
SL DMP
11D
HDOTDISP
DAD DSU
36D
/LAND/
STODL HCALC1 # UPDATE HCALC1 FOR NOUN 63.
HDOTDISP
BDSU DDV
VDGVERT
TAUROD
PDVL ABVAL # (2)
GDT/2
DDV SR2
GSCALE
STORE 20D
DAD # (0)
PDVL CALL # (2)
UNITX
CDU*NBSM
DOT
14D
STORE 22D
BDDV STADR # (0)
STOVL /AFC/
DELVROD
VXSC VAD
KPIP1
VBIAS
ABVAL PDDL # (2)
THISTPIP
DSU PDDL # (4)
LASTTPIP
THISTPIP
STODL LASTTPIP # (2)
DDV BDDV # (0)
SHFTFACT
PDDL DMP # (2)
FWEIGHT
BIT1H
DDV DDV
MASS
SCALEFAC
# Page 819
DAD PDDL # (4)
0D
20D
DDV DSU # (2)
22D
DMP DAD
LAG/TAU
/AFC/
PDDL DDV # (4)
MAXFORCE
MASS
PDDL DDV # (6)
MINFORCE
MASS
PUSH BDSU # (8)
2D
BMN DLOAD # (6)
AFCSPOT
DLOAD PUSH # (6)
BDSU BPL
2D
AFCSPOT
DLOAD # (4)
AFCSPOT DLOAD # (2), (4), OR (6)
SETPD # (2)
2D
STODL /AFC/ # (0)
ITRPNT2 EXIT
DXCH MPAC # MPAC = MEASURED ACCELERATION.
TC BANKCALL
CADR THROTTLE +3
TC INTPRET
VLOAD # PICK UP UPDATED VELOCITY VECTOR.
24D
VHORCOMP VSL2 VAD
DELVS
VSR2 PDVL
R
UNIT VXSC
HDOTDISP
VSL1 BVSU
ABVAL
STORE VHORIZ
EXIT
TC BANKCALL # PUT UP V06N60 DISPLAY BUT AVOID PHASCHNG
CADR DISPEXIT +3
BIT1H OCT 00001
SHFTFACT 2DEC 1 B-17
# Page 820
BIASFACT 2DEC 655.36 B-28
# *********************************************************************************
# REDESIGNATOR TRAP
# *********************************************************************************
BANK 11
SETLOC F2DPS*11
BANK
COUNT* $$/F2DPS
PITFALL XCH BANKRUPT
EXTEND
QXCH QRUPT
TC CHECKMM # IF NOT IN P64, NO REASON TO CONTINUE
DEC 64
TCF RESUME
EXTEND
READ CHAN31
COM
MASK ALL4BITS
TS ELVIRA
CAF TWO
TS ZERLINA
CAF FIVE
TC TWIDDLE
ADRES REDESMON
TCF RESUME
# REDESIGNATOR MONITOR (INITIATED BY PITFALL)
PREMON1 TS ZERLINA
PREMON2 CAF SEVEN
TC VARDELAY
REDESMON EXTEND
READ 31
COM
MASK ALL4BITS
XCH ELVIRA
TS L
CCS ELVIRA # DO ANY BITS APPEAR THIS PASS?
TCF PREMON2 # Y: CONTINUE MONITOR
CCS L # N: ANY LAST PASS?
TCF COUNT'EM # Y: COUNT 'EM, RESET RUPT, TERMINATE
# Page 821
CCS ZERLINA # N: HAS ZERLINA REACHED ZERO YET?
TCF PREMON1 # N: DIMINISH ZERLINA, CONTINUE
RESETRPT CAF BIT12 # Y: RESET RUPT. TERMINATE
EXTEND
WOR CHAN13
TCF TASKOVER
COUNT'EM CAF BIT13 # ARE WE IN ATTITUDE-HOLD?
EXTEND
RAND CHAN31
EXTEND
BZF RESETRPT # YES: SKIP REDESIGNATION LOGIC.
CA L # NO.
MASK -AZBIT
CCS A
-AZ CS AZEACH
ADS AZINCR1
CA L
MASK +AZBIT
CCS A
+AZ CA AZEACH
ADS AZINCR1
CA L
MASK -ELBIT
CCS A
-EL CS ELEACH
ADS ELINCR1
CA L
MASK +ELBIT
CCS A
+EL CA ELEACH
ADS ELINCR1
TCF RESETRPT
# THESE EQUIVALENCES ARE BASED ON GSOP CHAPTER 4, REVISION 16 OF P64LM
+ELBIT = BIT2 # -PITCH
-ELBIT = BIT1 # +PITCH
+AZBIT = BIT5
-AZBIT = BIT6
# Page 822
ALL4BITS OCT 00063
AZEACH DEC .03491 # 2 DEGREES
ELEACH DEC .00873 # 1/2 DEGREE
# ****************************************************************
# R.O.D. TRAP
# ****************************************************************
BANK 20
SETLOC RODTRAP
BANK
COUNT* $$/F2DPS # ************************
DESCBITS MASK BIT7 # COME HERE FROM MARKRUPT CODING WITH BIT
CCS A # 7 OR 6 OF CHANNEL 16 IN A; BIT 7 MEANS
CS TWO # - RATE INCREMENT, BIT 6 + INCREMENT.
AD ONE
ADS RODCOUNT
TCF RESUME # TRAP IS RESET WHEN SWITCH IS RELEASED
BANK 31
SETLOC F2DPS*31
BANK
COUNT* $$/F2DPS
# ***********************************************************************************
# DOUBLE PRECISION ROOT FINDER SUBROUTINE (BY ALLAN KLUMPP)
# ***********************************************************************************
#
# N N-1
# ROOTPSRS FINDS ONE ROOT OF THE POWER SERIES A X + A X + ... + A X + A
# N N-1 1 0
# USING NEWTON'S METHOD STARTING WITH AN INITIAL GUESS FOR THE ROOT. THE ENTERING DATA MUST BE AS FOLLOWS:
# A SP LOC-3 ADRES FOR REFERENCING PWR COF TABL
# L SP N-1 N IS THE DEGREE OF THE POWER SERIES
# MPAC DP X INITIAL GUESS FOR ROOT
#
# LOC-2N DP A(0)
# ...
# LOC DP A(N)
# LOC+2 SP PRECROOT PREC RQD OF ROOT (AS FRACT OF 1ST GUESS)
#
# Page 823
# THE DP RESULT IS LEFT IN MPAC UPON EXIT, AND A SP COUNT OF THE ITERATIONS TO CONVERGENCE IS LEFT IN MPAC+2.
# RETURN IS NORMALLY TO LOC(TC ROOTPSRS)+3. IF ROOTPSRS FAILS TO CONVERGE TO IN 8 PASSES, RETURN IS TO LOC+1 AND
# OUTPUTS ARE NOT TO BE TRUSTED.
#
# PRECAUTION: ROOTPSRS MAKES NO CHECKS FOR OVERFLOW OR FOR IMPROPER USAGE. IMPROPER USAGE COULD
# PRECLUDE CONVERGENCE OR REQUIRE EXCESSIVE ITERATIONS. AS A SPECIFIC EXAMPLE, ROOTPSRS FORMS A DERIVATIVE
# COEFFICIENT TABLE BY MULTIPLYING EACH A(I) BY I, WHERE I RANGES FROM 1 TO N. IF AN ELEMENT OF THE DERIVATIVE
# COEFFICIENT TABLE = 1 OR >1 IN MAGNITUDE, ONLY THE EXCESS IS RETAINED. ROOTPSRS MAY CONVERGE ON THE CORRECT
# ROOT NONETHELESS, BUT IT MAY TAKE AN EXCESSIVE NUMBER OF ITERATIONS. THEREFORE THE USER SHOULD RECOGNIZE:
# 1. USER'S RESPONSIBILITY TO ASSUR THAT I X A(I) < 1 IN MAGNITUDE FOR ALL I.
# 2. USER'S RESPONSIBILITY TO ASSURE OVERFLOW WILL NOT OCCUR IN EVALUATING EITHER THE RESIDUAL OR THE DERIVATIVE
# POWER SERIES. THIS OVERFLOW WOULD BE PRODUCED BY SUBROUTINE POWRSERS, CALLED BY ROOTPSRS, AND MIGHT NOT
# PRECLUDE EVENTUAL CONVERGENCE.
# 3. AT PRESENT, ERASABLE LOCATIONS ARE RESERVED ONLY FOR N UP TO 5. AN N IN EXCESS OF 5 WILL PRODUCE CHAOS.
# ALL ERASABLES USED BY ROOTPSRS ARE UNSWITCHED LOCATED IN THE REGION FROM MPAC-33 OCT TO MPAC+7.
# 4. THE ITERATION COUNT RETURNED IN MPAC+2 MAY BE USED TO DETECT ABNORMAL PERFORMANCE.
# STORE ENTERING DATA, INITIALIZE ERASABLES
ROOTPSRS EXTEND
QXCH RETROOT # RETURN ADRES
TS PWRPTR # PWR TABLE POINTER
DXCH MPAC +3 # PWR TABLE ADRES, N-1
CA DERTABLL
TS DERPTR # DER TABL POINTER
TS MPAC +5 # DER TABL ADRES
CCS MPAC +4 # NO POWER SERIES DEGREE 1 OR LESS
TS MPAC +6 # N-2
CA ZERO # MODE USED AS ITERATION COUNTER. MODE
TS MODE # MUST BE POS SO ABS WON'T COMP MPAC+3 ETC.
# COMPUTE CRITERION TO STOP ITERATING
EXTEND
DCA MPAC # FETCH ROOT GUESS, KEEPING IT IN MPAC
DXCH ROOTPS # AND IN ROOTPS
INDEX MPAC +3 # PWR TABLE ADRES
CA 5 # PRECROOT TO A
TC SHORTMP # YIELDS DP PRODUCT IN MPAC
TC USPRCADR
CADR ABS # YIELDS ABVAL OF CRITERION ON DX IN MPAC
DXCH MPAC
DXCH DXCRIT # CRITERION
# SET UP DER COF TABL
# Page 824
EXTEND
INDEX PWRPTR
DCA 3
DXCH MPAC # A(N) TO MPAC
CA MPAC +4 # N-1 TO A
DERCLOOP TS PWRCNT # LOOP COUNTER
AD ONE
TC DMPNSUB # YIELDS DERCOF = I X A(I) IN MPAC
EXTEND
INDEX PWRPTR
DCA 1
DXCH MPAC # (I-1) TO MPAC, FETCHING DERCOF
INDEX DERPTR
DXCH 3 # DERCOF TO DER TABLE
CS TWO
ADS PWRPTR # DECREMENT PWR POINTER
CS TWO
ADS DERPTR # DECREMENT DER POINTER
CCS PWRCNT
TCF DERCLOOP
# CONVERGE ON ROOT
ROOTLOOP EXTEND
DCA ROOTPS # FETCH CURRENT ROOT
DXCH MPAC # LEAVE IN MPAC
EXTEND
DCA MPAC +5 # LOAD A, L WITH DER TABL ADRES, N-2
TC POWRSERS # YIELDS DERIVATIVE IN MPAC
EXTEND
DCA ROOTPS
DXCH MPAC # CURRENT ROOT TO MPAC, FETCHING DERIVATIVE
DXCH BUF # LEAVE DERIVATIVE IN BUF AS DIVISOR
EXTEND
DCA MPAC +3 # LOAD A, L WITH PWR TABL ADRES, N-1
TC POWRSERS # YIELDS RESIDUAL IN MPAC
TC USPRCADR
CADR DDV/BDDV # YIELDS -DX IN MPAC
EXTEND
DCS MPAC # FETCH DX, LEAVING -DX IN MPAC
DAS ROOTPS # CORRECTED ROOT NOW IN ROOTPS
TC USPRCADR
CADR ABS # YIELDS ABS(DX) IN MPAC
EXTEND
# Page 825
DCS DXCRIT
DAS MPAC # ABS(DX)-ABS(DXCRIT) IN MPAC
CA MODE
MASK BIT4 # KLUMPP SAYS GIVE UP AFTER EIGHT PASSES
CCS A
BADROOT TC RETROOT
INCR MODE # INCREMENT ITERATION COUNTER
CCS MPAC # TEST HI ORDER DX
TCF ROOTLOOP
TCF TESTLODX
TCF ROOTSTOR
TESTLODX CCS MPAC +1 # TEST LO ORDER DX
TCF ROOTLOOP
TCF ROOTSTOR
TCF ROOTSTOR
ROOTSTOR DXCH ROOTPS
DXCH MPAC
CA MODE
TS MPAC +2 # STORE SP ITERATION COUNT IN MPAC+2
INDEX RETROOT
TCF 2
DERTABLL ADRES DERCOFN -3
# ****************************************************************************
# TRASHY LITTLE SUBROUTINES
# ****************************************************************************
INTPRETX INDEX WCHPHASE # SET X1 ON THE WAY TO THE INTERPRETER
CS TARGTDEX
INDEX FIXLOC
TS X1
TCF INTPRET
TDISPSET CA TTF/8
EXTEND
MP TSCALINV
DXCH TTFDISP
CA EBANK5 # TREDES BECOMES ZERO TWO PASSES
TS EBANK # BEFORE TCGFAPPR IS REACHED
EBANK= TCGFAPPR
CA TCGFAPPR
INCR BBANK
INCR BBANK
EBANK= TTF/8
# Page 826
AD TTF/8
EXTEND
MP TREDESCL
AD -DEC103
AD NEGMAX
TS L
CS L
AD L
AD +DEC99
AD POSMAX
TS TREDES
CS TREDES
ADS TREDES
TC Q
1406P00 TC P00DOO
OCT 01406
1406ALM TC ALARM
OCT 01406
TCF RATESTOP
# *********************************************************************
# SPECIALIZED "PHASCHNG" SUBROUTINE
# *********************************************************************
EBANK= PHSNAME2
FASTCHNG CA EBANK3 # SPECIALIZED 'PHASCHNG' ROUTINE
XCH EBANK
DXCH L
TS PHSNAME3
LXCH EBANK
EBANK= E2DPS
TC A
# *************************************************************************************
# PARAMETER TABLE INDIRECT ADDRESSES
# *************************************************************************************
RDG = RBRFG
VDG = VBRFG
ADG = ABRFG
VDG2TTF = VBRFG*
ADG2TTF = ABRFG*
JDG2TTF = JBRFG*
# *************************************************************************************
# LUNAR LANDING CONSTANTS
# *************************************************************************************
# Page 827
TABLTTFL ADRES TABLTTF +3 # ADDRESS FOR REFERENCING TTF TABLE
TTFSCALE = BIT12
TSCALINV = BIT4
-DEC103 DEC -103
+DEC99 DEC +99
TREDESCL DEC -.08
180DEGS DEC +180
1/2DEG DEC +.00278
PROJMAX DEC .42262 B-3 # SIN(25')/8 TO COMPARE WITH PROJ
PROJMIN DEC .25882 B-3 # SIN(15')/8 TO COMPARE WITH PROJ
V06N63 VN 0663 # P63
V06N64 VN 0664 # P64
V06N60 VN 0660 # P65, P66, P67
BANK 22
SETLOC LANDCNST
BANK
COUNT* $$/F2DPS
HIGHESTF 2DEC 4.34546769 B-12
GSCALE 2DEC 100 B-11
3/8DP 2DEC .375
3/4DP 2DEC .750
DEPRCRIT 2DEC -.02 B-1
# Page 828
# **************************************************************************
# **************************************************************************