LANDING_ANALOG_DISPLAYS.agc
### FILE="Main.annotation"
## Copyright: Public domain.
## Filename: LANDING_ANALOG_DISPLAYS.agc
## Purpose: A section of a reconstructed, mixed version of Sundance
## It is part of the reconstructed source code for the Lunar
## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 9.
## No original listings of this program are available;
## instead, this file was created via disassembly of dumps
## of various revisions of Sundance core rope modules.
## Assembler: yaYUL
## Contact: Ron Burkey <info@sandroid.org>.
## Website: www.ibiblio.org/apollo/index.html
## Mod history: 2020-06-17 MAS Created from Luminary 69.
## Sundance 302
BANK 21
SETLOC R10
BANK
EBANK= UNIT/R/
COUNT* $$/R10
LANDISP CAF SWANDBIT # IS LANDING ANALOG DISPLAYS FLAG SET?
MASK FLAGWRD7
CCS A
TCF +3 # YES.
GODSPRST TC DISPRSET # NO.
TCF LANDELAY
CA IMODES33 # BIT 7 = 0 (DO ALTRATE), =1 (DO ALT.)
MASK BIT7
CCS A
TCF ALTOUT
ALTROUT TC DISINDAT # CHECK MODE SELECT SWITCH AND DIDFLG.
CS IMODES33
MASK BIT7
ADS IMODES33 # ALTERNATE ALTITUDE RATE WITH ALTITUDE.
CAF BIT2 # RATE COMMAND IS EXECUTED BEFORE RANGE.
EXTEND
WOR CHAN14 # ALTRATE (BIT2 = 1), ALTITUDE (BIT2 = 0).
ARCOMP CA RUNIT # COMPUTE ALTRATE = RUNIT.VVECT M/CS *2(-6).
EXTEND
MP VVECT # MULTIPLY X-COMPONENTS.
XCH RUPTREG1 # SAVE SINGLE PRECISION RESULT M/CS*2(-6).
CA RUNIT +2 # MULTIPLY Y-COMPONENTS.
EXTEND
MP VVECT +1
ADS RUPTREG1 # ACCUMULATE PARTIAL PRODUCTS.
CA RUNIT +4 # MULTIPLY Z-COMPONENTS.
EXTEND
MP VVECT +2
ADS RUPTREG1 # ALTITUDE RATE IN M/CS *2(-6).
CA ARCONV # CONVERT ALTRATE TO BIT UNITS (.5FPS/BIT)
EXTEND
MP RUPTREG1
DOUBLE
DOUBLE
XCH RUPTREG1 # ALTITUDE RATE IN BIT UNITS*2(-14).
CS DALTRATE # ALTITUDE RATE COMPENSATION FACTOR.
EXTEND
MP DT
AD RUPTREG1
TS ALTRATE # ALTITUDE RATE IN BIT UNITS*2(-14).
CS ALTRATE
EXTEND # CHECK POLARITY OF ALTITUDE RATE.
BZMF +2
TCF DATAOUT # NEGATIVE - SEND POS. PULSES TO ALTM REG.
CA ALTRATE # POSITIVE OR ZERO - SET SIGN BIT = 1 AND
AD BIT15 # SEND TO ALTM REGISTER. *DO NOT SEND +0*
DATAOUT TS ALTM # ACTIVATE THE LANDING ANALOG DISPLAYS - -
CAF DATABITS
EXTEND
WOR CHAN14 # BIT3 DRIVES THE ALT/ALTRATE METER.
LANDELAY CCS PIPCTR
TCF +2
TCF TASKOVER
TS PIPCTR
TC FIXDELAY
DEC 24
TCF LANDISP
ALTOUT TC DISINDAT # CHECK MODE SELECT SWITCH AND DIDFLG.
CS BIT7
MASK IMODES33
TS IMODES33 # ALTERNATE ALTITUDE RATE WITH ALTITUDE.
CS BIT2
EXTEND
WAND CHAN14
CCS ALTBITS # =-1 IF OLD ALT. DATA TO BE EXTRAPOLATED.
TCF +4
TCF +3
TCF OLDDATA
TS ALTBITS # SET ALTBITS FROM -0 TO +0.
CS ONE
DXCH ALTBITS # SET ALTBITS = -1 FOR SWITCH USE NEXT PASS.
ZDATA2 DXCH ALTSAVE
TCF NEWDATA
OLDDATA CA ALTRATE # RATE APPLIES FOR .5 SEC. (4X/SEC. CYCLE)
EXTEND
MP ARTOA # EXTRAPOLATE WITH ALTITUDE RATE.
AD ALTSAVE +1
TS ALTSAVE +1
CAF ZERO
ADS ALTSAVE
CAF POSMAX # FORCE SIGN AGREEMENT ASSUMING A
AD ONE # NON-NEGATIVE ALTSAVE.
AD ALTSAVE +1 # IF ALTSAVE IS NEGATIVE, ZERO ALTSAVE
TS ALTSAVE +1 # AND ALTSAVE +1 AT ZERODATA.
CAF ZERO
AD POSMAX
AD ALTSAVE
TS ALTSAVE # POSSIBLY SKIP TO NEWDATA.
TCF ZERODATA
NEWDATA CCS ALTSAVE +1
TCF +4
TCF +3
CAF ZERO # SET NEGATIVE ALTSAVE +1 TO +0.
TS ALTSAVE +1
CCS ALTSAVE # PROVIDE A 15 BIT UNSIGNED OUTPUT.
CAF BIT15 # THE HI-ORDER PART IS +1 OR +0.
AD ALTSAVE +1
TCF DATAOUT # DISPATCH UNSIGNED BITS TO ALTM REG.
DISINDAT EXTEND
QXCH LADQSAVE # SAVE RETURN TO ALTROUT +1 OR ALTOUT +1
CAF BIT6
EXTEND # WISHETH THE ASTRONAUT THE ANALOG
RAND CHAN30 # DISPLAYS? I.E.,
CCS A # IS THE MODE SELECT SWITCH IN PGNCS?
TCF GODSPRST # NO. ASTRONAUT REQUESTS NO INERTIAL DATA
CCS DIDFLG # YES. CHECK STATUS OF DIDFLAG.
TCF GODSPRST
TCF SPEEDRUN # SET. PERFORM DATA DISPLAY SEQUENCE.
CAF BIT8
EXTEND
WOR CHAN12 # SET DISPLAY INERTIAL DATA OUTBIT.
CAF ZERO
TS DIDFLG
TS TRAKLATV # LATERAL VELOCITY MONITOR FLAG
TS TRAKFWDV # FORWARD VELOCITY MONITOR FLAG
TS LATVMETR # LATVEL MONITOR METER
TS FORVMETR # FORVEL MONITOR METER
CS BIT7
MASK IMODES33
TS IMODES33
CAF BIT4
TC TWIDDLE
ADRES INTLZE
TCF LANDELAY
INTLZE CAF BIT2
EXTEND
WOR CHAN12 # ENABLE RR ERROR COUNTER.
CS IMODES33
MASK BIT8
ADS IMODES33 # SET INERTIAL DATA FLAG.
TCF TASKOVER
SPEEDRUN CS PIPTIME +1 # UPDATE THE VELOCITY VECTOR
AD TIME1 # COMPUTE T - TN
AD HALF # CORRECT FOR POSSIBLE OVERFLOW OF TIME1.
AD HALF
XCH DT # SAVE FOR LATER USE
CA 1SEC
TS ITEMP5 # INITIALIZE FOR DIVISION LATER
EXTEND
DCA GDT/2 # COMPUTE THE X-COMPONENT OF VELOCITY.
DDOUBL
DDOUBL
EXTEND
MP DT
EXTEND
DV ITEMP5
XCH VVECT # VVECT = G(T-TN) M/CS *2(-5)
EXTEND
DCA V # M/CS *2(-7)
DDOUBL # RESCALE TO 2(-5)
DDOUBL
ADS VVECT # VVECT = VN + G(T-TN) M/CS *2(-5)
CA PIPAX # DELV CM/SEC *2(-14)
AD PIPATMPX # IN CASE PIPAX HAS BEEN ZEROED
EXTEND
MP KPIP1(5) # DELV M/CS *2(-5)
ADS VVECT # VVECT = VN + DELV + GN(T-TN) M/CS *2(-5)
EXTEND
DCA GDT/2 +2 # COMPUTE THE Y-COMPONENT OF VELOCITY.
DDOUBL
DDOUBL
EXTEND
MP DT
EXTEND
DV ITEMP5
XCH VVECT +1
EXTEND
DCA V +2
DDOUBL
DDOUBL
ADS VVECT +1
CA PIPAY
AD PIPATMPY
EXTEND
MP KPIP1(5)
ADS VVECT +1
EXTEND
DCA GDT/2 +4 # COMPUTE THE Z-COMPONENT OF VELOCITY.
DDOUBL
DDOUBL
EXTEND
MP DT
EXTEND
DV ITEMP5
XCH VVECT +2
EXTEND
DCA V +4
DDOUBL
DDOUBL
ADS VVECT +2
CA PIPAZ
AD PIPATMPZ
EXTEND
MP KPIP1(5)
ADS VVECT +2
CS DELVS # HI X OF VELOCITY CORRECTION TERM.
AD VVECT # HI X OF UPDATED VELOCITY VECTOR.
TS ITEMP1 # = VX - DVX M/CS *2(-5).
CS DELVS +2 # Y
AD VVECT +1 # Y
TS ITEMP2 # = VY - DVY M/CS *2(-5).
CS DELVS +4 # Z
AD VVECT +2 # Z
TS ITEMP3 # = VZ - DVZ M/CS *2(-5).
CA ITEMP1 # COMPUTE VHY, VELOCITY DIRECTED ALONG THE
EXTEND # Y-COORDINATE.
MP UHYP # HI X OF CROSS-RANGE HALF-UNIT VECTOR.
XCH RUPTREG1
CA ITEMP2
EXTEND
MP UHYP +2 # Y
ADS RUPTREG1 # ACCUMULATE PARTIAL PRODUCTS.
CA ITEMP3
EXTEND
MP UHYP +4 # Z
ADS RUPTREG1
CA RUPTREG1
DOUBLE
XCH VHY # VHY=VMP.UHYP M/CS*2(-5).
CA ITEMP1 # NOW COMPUTE VHZ, VELOCITY DIRECTED ALONG
EXTEND # THE Z-COORDINATE.
MP UHZP # HI X OF DOWN-RANGE HALF-UNIT VECTOR.
XCH RUPTREG1
CA ITEMP2
EXTEND
MP UHZP +2 # Y
ADS RUPTREG1 # ACCUMULATE PARTIAL PRODUCTS.
CA ITEMP3
EXTEND
MP UHZP +4 # Z
ADS RUPTREG1
CA RUPTREG1
DOUBLE
XCH VHZ # VHZ = VMP.UHZP M/CS*2(-5).
GET22/32 CAF EBANK6 # GET SIN(AOG),COS(AOG) FROM GPMATRIX.
TS EBANK
EBANK= M22
CA M22
TS ITEMP3
CA M32
TS ITEMP4
CAF EBANK7
TS EBANK
EBANK= UNIT/R/
LATFWDV CA ITEMP4 # COMPUTE LATERAL AND FORWARD VELOCITIES.
EXTEND
MP VHY
XCH RUPTREG1
CA ITEMP3
EXTEND
MP VHZ
ADS RUPTREG1 # = VHY(COS)AOG+VHZ(SIN)AOG M/CS *2(-5)
CA VELCONV # CONVERT LATERAL VELOCITY TO BIT UNITS.
EXTEND
MP RUPTREG1
DOUBLE
XCH LATVEL # LATERAL VELOCITY IN BIT UNITS *2(-14).
CA ITEMP4 # COMPUTE FORWARD VELOCITY.
EXTEND
MP VHZ
XCH RUPTREG1
CA ITEMP3
EXTEND
MP VHY
CS A
ADS RUPTREG1 # =VHZ(COS)AOG-VHY(SIN)AOG M/CS *2(-5).
CA VELCONV # CONVERT FORWARD VELOCITY TO BIT UNITS.
EXTEND
MP RUPTREG1
DOUBLE
XCH FORVEL # FORWARD VELOCITY IN BIT UNITS *2(-14).
CS MAXVBITS # ACC.=-199.9989 FT./SEC.
TS ITEMP6 # -547 BIT UNITS (OCTAL) AT 0.5571 FPS/BIT
VMONITOR CCS LATVEL
TCF +4
TCF LVLIMITS
TCF +7
TCF LVLIMITS
CS LATVEL
AD MAXVBITS # +199.9989 FT./SEC.
EXTEND
BZMF CHKLASTY
TCF LVLIMITS
CA LATVEL
AD MAXVBITS
EXTEND
BZMF +2
TCF LVLIMITS
CHKLASTY CCS TRAKLATV
TCF LASTPOSY
TCF +2
TCF LASTNEGY
CA LATVEL
EXTEND
BZMF NEGVMAXY
TCF POSVMAXY
LASTPOSY CA LATVEL
EXTEND
BZMF +2
TCF POSVMAXY
CS MAXVBITS
TCF ZEROLSTY
POSVMAXY CS LATVMETR
AD MAXVBITS
XCH RUPTREG3
CAF ONE
TCF ZEROLSTY +2
LASTNEGY CA LATVEL
EXTEND
BZMF NEGVMAXY
CA MAXVBITS
TCF ZEROLSTY
NEGVMAXY CA LATVMETR
AD MAXVBITS
COM
XCH RUPTREG3
CS ONE
TCF ZEROLSTY +2
LVLIMITS CCS TRAKLATV
TCF LATVPOS
TCF +2
TCF LATVNEG
CS LATVMETR
EXTEND
BZMF +2
TCF NEGLMLV
CS LATVEL
EXTEND
BZMF LVMINLM
AD ITEMP6
AD LATVMETR
EXTEND
BZMF LVMINLM
AD LATVEL
EXTEND
SU LATVMETR
TCF ZEROLSTY
LATVPOS CS LATVEL
EXTEND
BZMF LVMINLM
TCF +4
LATVNEG CA LATVEL
EXTEND
BZMF LVMINLM
CS LATVMETR
TCF ZEROLSTY
NEGLMLV CA LATVEL
EXTEND
BZMF LVMINLM
CA MAXVBITS
AD LATVMETR
COM
AD LATVEL
EXTEND
BZMF LVMINLM
EXTEND
SU LATVEL
AD LATVMETR
COM
TCF ZEROLSTY
LVMINLM CS LATVMETR
AD LATVEL
ZEROLSTY XCH RUPTREG3
CAF ZERO
TS TRAKLATV
CA RUPTREG3
AD NEG0 # AVOIDS +0 DINC HARDWARE MALFUNCTION
TS CDUTCMD
CA RUPTREG3
ADS LATVMETR
CCS FORVEL
TCF +4
TCF FVLIMITS
TCF +7
TCF FVLIMITS
CS FORVEL
AD MAXVBITS # +199.9989 FT./SEC.
EXTEND
BZMF CHKLASTZ
TCF FVLIMITS
CA FORVEL
AD MAXVBITS
EXTEND
BZMF +2
TCF FVLIMITS
CHKLASTZ CCS TRAKFWDV
TCF LASTPOSZ
TCF +2
TCF LASTNEGZ
CA FORVEL
EXTEND
BZMF NEGVMAXZ
TCF POSVMAXZ
LASTPOSZ CA FORVEL
EXTEND
BZMF +2
TCF POSVMAXZ
CS MAXVBITS
TCF ZEROLSTZ
POSVMAXZ CS FORVMETR
AD MAXVBITS
XCH RUPTREG4
CAF ONE
TCF ZEROLSTZ +2
LASTNEGZ CA FORVEL
EXTEND
BZMF NEGVMAXZ
CA MAXVBITS
TCF ZEROLSTZ
NEGVMAXZ CA FORVMETR
AD MAXVBITS
COM
XCH RUPTREG4
CS ONE
TCF ZEROLSTZ +2
FVLIMITS CCS TRAKFWDV
TCF FORVPOS
TCF +2
TCF FORVNEG
CS FORVMETR
EXTEND
BZMF +2
TCF NEGLMFV
CS FORVEL
EXTEND
BZMF FVMINLM
AD ITEMP6
AD FORVMETR
EXTEND
BZMF FVMINLM
AD FORVEL
EXTEND
SU FORVMETR
TCF ZEROLSTZ
FORVPOS CS FORVEL
EXTEND
BZMF FVMINLM
TCF +4
FORVNEG CA FORVEL
EXTEND
BZMF FVMINLM
CS FORVMETR
TCF ZEROLSTZ
NEGLMFV CA FORVEL
EXTEND
BZMF FVMINLM
CA MAXVBITS
AD FORVMETR
COM
AD FORVEL
EXTEND
BZMF FVMINLM
EXTEND
SU FORVEL
AD FORVMETR
COM
TCF ZEROLSTZ
FVMINLM CS FORVMETR
AD FORVEL
ZEROLSTZ XCH RUPTREG4
CAF ZERO
TS TRAKFWDV
CA RUPTREG4
AD NEG0 # AVOIDS +0 DINC HARDWARE MALFUNCTION
TS CDUSCMD
CA RUPTREG4
ADS FORVMETR
TC LADQSAVE # GO TO ALTROUT +1 OR TO ALTOUT +1
ZERODATA CAF ZERO # ZERO ALTSAVE AND ALTSAVE +1 - - -
TS L # NO NEGATIVE ALTITUDES ALLOWED.
TCF ZDATA2
# ************************************************************************
DISPRSET CAF BIT8
MASK IMODES33 # CHECK IF INERTIAL DATA JUST DISPLAYED.
CCS A
CAF BIT2 # YES. DISABLE RR ERROR COUNTER
AD BIT8 # NO. REMOVE DISPLAY INERTIAL DATA
COM
EXTEND
WAND CHAN12
CS BITS8/7 # RESET INERTIAL DATA, INTERLEAVE FLAGS.
MASK IMODES33
TS IMODES33
CS ONE
TS DIDFLG
TC Q
# ************************************************************************
BITS8/7 OCT 00300 # INERTIAL DATA AND INTERLEAVE FLAGS.
BITSET = PRIO6
ARCONV OCT 24402 # 656.1679798B-10 CONV ALTRATE TO BIT UNIT
ARTOA DEC .2051 B-1
DATABITS OCT 06004
VELCONV OCT 22316 # 588.914 B-10 CONV VEL. TO BIT UNITS.
KPIP1(5) DEC .05115 # SCALES DELV TO M/CS*2(-5).
OCT33427 OCT 33427
MAXVBITS OCT 00547 # MAX. DISPLAYED VELOCITY 199.9989 FT/SEC.
# ************************************************************************
