R63

Scanned pages: 338-341

R63.agc

# Copyright:  Public domain.
# Filename:  R63.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:  Ron Burkey <info@sandroid.org>.
# Website:  www.ibiblio.org/apollo.
# Pages:  338-341
# Mod history:  2009-05-16 RSB  Adapted from the corresponding
#        Luminary131 file, using page
#        images from Luminary 1A.
#
# 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 338
# SUBROUTINE NAME:  V89CALL
# MOD NO:  0      DATE:    9 JAN 1968
# MOD BY:  DIGITAL DEVEL GROUP  LOG SECTION:  R63
#
# FUNCTIONAL DESCRIPTION:
#
# CALLED BY VERB 89 ENTER DURING P00.  PRIO 10 USED.  CALCULATES AND
# DISPLAYS FINAL FDAI BALL ANGLES TO POINT LM +X OR +Z AXIS AT CSM.
#
# 1. KEY IN V 89 E ONLY IF IN PROG 00.  IF NOT IN P00, OPERATOR ERROR AND
# EXIT R63, OTHERWISE CONTINUE.
#
# 2. IF IN P00, DO IMU STATUS CHECK ROUTINE (R02BOTH).  IF IMU ON AND ITS
# ORIENTATION KNOWN TO LGC, CONTINUE.
#
# 3. FLASH DISPLAY V 04 N 06.  R2 INDICATES WHICH SPACECRAFT AXIS IS TO
# BE POINTED AT CSM.  INITIAL CHOICE IS PREFERRED (+Z) AXIS (R2=1).
# ASTRONAUT CAN CHANGE TO (+X) AXIS (R2 NOT = 1) BY V 22 E 2 E.  CONTINUE
# AFTER KEYING IN PROCEED.
#
# 4. BOTH VEHICLE STATE VECTORS UPDATED BY CONIC EQS.
#
# 5. HALF MAGNITUDE UNIT LOS VECTOR (IN STABLE MEMBER COORDINATES) AND
# HALF MAGNITUDE UNIT SPACECRAFT AXIS VECTOR (IN BODY COORDINATES)
# PREPARED FOR VECPOINT.
#
# 6. GIMBAL ANGLES FROM VECPOINT TRANSFORMED INTO FDAI BALL ANGLES BY
# BALLANGS.  FLASH DISPLAY V 06 N 18 AND AWAIT RESPONSE.
#
# 7. RECYCLE - RETURN TO STEP 4.
#    TERMINATE - EXIT R63.
#    PROCEED - RESET 3AXISFLG AND CALL R60LEM FOR ATTITUDE MANEUVER.
#
# CALLING SEQUENCE:  V 89 E.
#
# SUBROUTINES CALLED:  CHKPOOH, R02BOTH, GOXDSPF, CSMCONIC, LEMCONIC,
#      VECPOINT, BALLANGS, R60LEM.
#
# NORMAL EXIT MODES:   TC ENDEXT
#
# ALARMS:  1. OPERATOR ERROR IF NOT IN P00.
#    2. PROGRAM ALARM IF IMU IS OFF.
#    3. PROGRAM ALARM IF IMU ORIENTATION IS UNKNOWN.
#
# OUTPUT:  NONE
#
# ERASABLE INITIALIZATION REQUIRED:  NONE
#
# DEBRIS:  OPTION1, +1, TDEC1, PDINTVSM, SCAXIS, CPHI, CTHETA, CPSI,
# Page 339
#    3AXISFLG.

    EBANK=  RONE
    BANK  32
    SETLOC  BAWLANGS
    BANK

    COUNT*  $$/R63
V89CALL    TC  BANKCALL  # IMU STATUS CHECK.  RETURNS IF ORIENTATION
    CADR  R02BOTH    # KNOWN.  ALARMS IF NOT.
    CAF  THREE    # ALLOW ASTRONAUT TO SELECT DESIRED
    TS  OPTIONX    # TRACKING ATTITUDE AXIS.
    CAF  ONE
    TS  OPTIONX  +1
    CAF  VB04N12    # V 04 N 12
    TC  BANKCALL
    CADR  GOFLASH
    TC  ENDEXT    # TERMINATE
    TC   +2    # PROCEED
    TC  -5    # DATA IN.  OPTION1+1 = 1 FOR Z AXIS
V89RECL    TC  INTPRET    #      = 2 FOR X AXIS
    RTB  DAD
      LOADTIME  # READ PRESENT TIME
      DP1MIN
    STORE  TSTART82  # SAVE TIME FOR LEMCONIC CALL
    STCALL  TDEC1    # STORE TIME FOR CSMCONIC CALL
      CSMCONIC  # CSM STATE VECTOR UPDATE
    VLOAD      # CSMCONIC LEFT R VECTOR IN RATT
      RATT
    STODL  RONE    # SAVE FOR LINE OF SIGHT (LOS) COMPUTATION
      TSTART82
    STCALL  TDEC1    # STORE TIME FOR LEMCONIC CALL
      LEMCONIC  # LEM STATE VECTOR UPDATE
    VLOAD  VSU    # CSM POSITION - LEM POSITION = LOS
      RONE    # LOS VECTOR LEFT IN MPAC
      RATT
    MXV  RTB    # (REFSMAT X LOS).  TRANSFORMS LOS FROM
      REFSMMAT  # REFERENCE COORD TO STAB MEMB COORD.
      NORMUNIT
    STORE  POINTVSM  # STORE LOS FOR VECPOINT CALCULATION
    EXIT
    CS  OPTIONX +1  # 1 FOR Z AXIS.  2 FOR X AXIS.
    AD  ONE
    EXTEND
    BZF  ALINEZ
ALINEX    TC  INTPRET    # X AXIS ALIGNMENT
    VLOAD
      UNITX    # READ (.5, 0, 0)
# Page 340
V89CALL1  STCALL  SCAXIS    # STORE SELECTED ALIGNMENT AXIS
      VECPOINT  # PUTS DESIRED GIM ANG (OG,IG,MG) IN TMPAC
    STORE  CPHI    # STORE GIMBAL ANGLES FOR BALLANGS CALL.
    EXIT
    TC  BANKCALL
    CADR  BALLANGS  # PUTS DESIRED BALL ANGLE IN FDAIX,Y,Z
    CAF  VB06N18    # V 06 N 18
    TC  BANKCALL  # NOUN 18 REFERS TO FDAIX,Y,Z
    CADR  GOFLASH
    TC  ENDEXT    # TERMINATE
    TC  +2    # PROCEED
    TC  V89RECL    # RECYCLE
    TC  DOWNFLAG  # RESET 3 AXIS FLAG
    ADRES  3AXISFLG  # RESET BIT6 FLAG WORD 5
    TC  BANKCALL  # PERFORMS LEM MANEUVER TO ALIGN SELECTED
    CADR  R60LEM    # SPACECRAFT AXIS TO CSM.
    TCF  ENDEXT    # TERMINATE R63

ALINEZ    TC  INTPRET    # Z AXIS ALIGNMENT
    VLOAD  GOTO
      UNITZ    # READ (0, 0, .5)
      V89CALL1

VB04N12    VN  412
VB06N18    VN  0618
# Page 341
DP1MIN    2DEC  6000