### FILE="Main.annotation"
## Copyright:   Public domain.
## Filename:    P12.agc
## Purpose:     A section of Luminary revision 163.
##              It is part of the reconstructed source code for the first
##              (unflown) release of the flight software for the Lunar
##              Module's (LM) Apollo Guidance Computer (AGC) for Apollo 14.
##              The code has been recreated from a reconstructed copy of
##              Luminary 173, as well as Luminary memos 157 amd 158.
##              It has been adapted such that the resulting bugger words
##              exactly match those specified for Luminary 163 in NASA
##              drawing 2021152N, which gives relatively high confidence
##              that the reconstruction is correct.
## Reference:   pp. 829-833
## Assembler:   yaYUL
## Contact:     Ron Burkey <info@sandroid.org>.
## Website:     www.ibiblio.org/apollo/index.html
## Mod history: 2019-08-21 MAS  Created from Luminary 173.

## Page 829
                BANK    24
                SETLOC  P12
                BANK

                EBANK=  DVCNTR
                COUNT*  $$/P12

P12LM           TC      PHASCHNG
                OCT     04024

                TC      BANKCALL
                CADR    R02BOTH         # CHECK THE STATUS OF THE IMU.
                
                CAF     THRESH2         # INITIALIZE DVMON
                TS      DVTHRUSH
                CAF     FOUR
                TS      DVCNTR

                CAF     V06N33A
                TC      BANKCALL        # FLASH TIG
                CADR    GOFLASH
                TCF     GOTOPOOH
                TCF     +2              # PROCEED
                TCF     -5              # ENTER

                TC      PHASCHNG
                OCT     04024

                TC      INTPRET
                SET     SET
                        MUNFLAG
                        ACC4-2FL
                SET     CLEAR
                        R10FLAG
                        RNDVZFLG
                SET     SET
                        FLPI
                        FLVR
                CALL
                        GUIDINIT
                CALL
                        P12INIT
P12LMB          DLOAD
                        (TGO)A          # SET TGO TO AN INITIAL NOMINAL VALUE.
                STODL   TGO
                        TIG
                STCALL  TDEC1
                        LEMPREC         # ROTATE THE STATE VECTORS TO THE
                VLOAD   MXV             # IGNITION TIME.
## Page 830
                        VATT
                        REFSMMAT
                VSL1
                STOVL   V1S             # COMPUTE V1S = VEL(TIG)*2(-7)M/CS.
                        RATT
                MXV     VSL6
                        REFSMMAT
                STCALL  R               # COMPUTE R = POS(TIG)*2(-24) M.
                        MUNGRAV         # COMPUTE GDT1/2(TIG)*2(-7)M/CS.
                VLOAD   UNIT
                        R
                STCALL  UNIT/R/         # COMPUTE UNIT/R/ FOR YCOMP.
                        YCOMP
                SR      DCOMP
                        5D
                STODL   XRANGE          # INITIALIZE XRANGE FOR NOUN 76.
                        VINJNOM
                STODL   ZDOTD
                        RDOTDNOM
                STORE   RDOTD
                EXIT

                TC      PHASCHNG
                OCT     04024

NEWLOAD         CAF     V06N76          # FLASH CROSS-RANGE AND APOLUNE VALUES.
                TC      BANKCALL
                CADR    GOFLASH
                TCF     GOTOPOOH
                TCF     +2              # PROCEED
                TCF     NEWLOAD         # ENTER NEW DATA.

                CAF     P12ADRES
                TS      WHICH

                TC      PHASCHNG
                OCT     04024

                TC      INTPRET
                DLOAD   SL
                        XRANGE
                        5D
                DAD
                        Y
                STOVL   YCO
                        UNIT/R/
                VXSC    VAD
                        49FPS
                        V1S
                STORE   V               # V(TIPOVER) = V(IGN) + 57FPS (UNIT/R/)
## Page 831
                DOT     SL1
                        UNIT/R/
                STOVL   RDOT            # RDOT * 2(-7)
                        UNIT/R/
                VXV     UNIT
                        QAXIS
                STCALL  ZAXIS1
                        ASCENT
P12RET          DLOAD
                        ATP             # ATP(2)*2(18)
                DSQ     PDDL
                        ATY             # ATY(2)*2(18)
                DSQ     DAD
                BZE     SQRT
                        YAWDUN
                SL1     BDDV
                        ATY
                ARCSIN
YAWDUN          STOVL   YAW
                        UNFC/2
                UNIT    DOT
                        UNIT/R/
                SL1     ARCCOS
                DCOMP
                STORE   PITCH
                EXIT
                TC      PHASCHNG
                OCT     04024

                INHINT
                TC      IBNKCALL
                CADR    PFLITEDB
                TC      DOWNFLAG
                ADRES   FLPI

                TC      POSTJUMP
                CADR    BURNBABY

P12INIT         DLOAD                   # INITIALIZE ENGINE DATA. USED FOR P12 AND
                        (1/DV)A         # P71.
                STORE   1/DV3
                STORE   1/DV2
                STODL   1/DV1
                        (AT)A
                STODL   AT
                        (TBUP)A
                STODL   TBUP
                        ATDECAY
                DCOMP   SL
                        11D
                STORE   TTO
                SLOAD   DCOMP
                        APSVEX
                SR2
## Page 832
                STORE   VE
                BOFF    RVQ
                        FLAP
                        COMMINIT
COMMINIT        DLOAD   DAD             # INITIALIZE TARGET DATA. USED BY P12, P70
                        HINJECT         # AND P71 IF IT DOES NOT FOLLOW P70.
                        /LAND/
                STODL   RCO
                        HI6ZEROS
                STORE   TXO
                STORE   YCO
                STOVL   YDOTD
                        VRECTCSM
                VXV     MXV
                        RRECTCSM
                        REFSMMAT
                UNIT
                STORE   QAXIS
                RVQ

P12ADRES        REMADR  P12TABLE

                SETLOC  ASENT8
                BANK
                COUNT*  $$/P12

GUIDINIT        STQ     SETPD
                        TEMPR60
                        0D
                VLOAD   PUSH
                        UNITZ
                RTB     PUSH
                        LOADTIME
                CALL
                        RP-TO-R
                MXV     VXSC
                        REFSMMAT
                        MOONRATE
                STOVL   WM
                        RLS
                ABVAL   SL3
                STCALL  /LAND/
                        TEMPR60

49FPS           2DEC    .149352 B-6     # EXPECTED RDOT AT TIPOVER

VINJNOM         2DEC    16.7924 B-7     # 5509.5 FPS(APO=30NM WITH RDOT=19.5FPS)

RDOTDNOM        2DEC    .059436 B-7     # 19.5 FPS

## Page 833
## This page is empty in the hardcopy of the original assembly listing.