T6 RUPT PROGRAMS

Scanned pages: 1403-1405

T6-RUPT_PROGRAMS.agc

# Copyright:  Public domain.
# Filename:  T6-RUPT_PROGRAMS.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:  1403-1405
# Mod history:  2009-05-10 SN   (Sergio Navarro).  Started adapting
#        from the Luminary131/ file of the same
#        name, using Luminary099 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 1403
# PROGRAM NAMES:  (1) T6JOBCHK  MOD. NO. 5  OCTOBER 2, 1967
#      (2) DOT6RUPT
# MODIFICATION BY:  LOWELL G. HULL (A.C.ELECTRONICS)
#
# THESE PROGRAMS ENABLE THE LM DAP TO CONTROL THE THRUST TIMES OF THE REACTION CONTROL SYSTEM JETS BY USING TIME6.
# SINCE THE LM DAP MAINTAINS EXCLUSIVE CONTROL OVER TIME6 AND ITS INTERRUPTS, THE FOLLOWING CONVENTIONS HAVE BEEN
# ESTABLISHED AND MUST NOT BE TAMPERED WITH:
#  1.  NO NUMBER IS EVER PLACED INTO TIME6 EXCEPT BY LM DAP.
#  2.  NO PROGRAM OTHER THAN LM DAP ENABLES THE TIME6 COUNTER.
#  3.  TO USE TIME6, THE FOLLOWING SEQUENCE IS ALWAYS EMPLOYED:
#    A.  A POSITIVE (NON-ZERO) NUMBER IS STORED IN TIME6.
#    B.  THE TIME6 CLOCK IS ENABLED.
#    C.  TIME6 IS INTERROGATED AND IS:
#      I.  NEVER FOUND NEGATIVE (NON-ZERO) OR +0.
#      II.  SOMETIMES FOUND POSITIVE (BETWEEN 1 AND 240D) INDICATING THAT IT IS ACTIVE.
#      III.  SOMETIMES FOUND POSMAX INDICATING THAT IT IS INACTIVE AND NOT ENABLED.
#      IV.  SOMETIMES FOUND NEGATIVE ZERO INDICATING THAT:
#        A.  A T6RUPT IS ABOUT TO OCCUR AT THE NEXT DINC, OR
#        B.  A T6RUPT IS WAITING IN THE PRIORITY CHAIN, OR
#        C.  A T6RUPT IS IN PROCESS NOW.
#  4.  ALL PROGRAMS WHICH OPERATE IN EITHER INTERRUPT MODE OR WITH INTERRUPT INHIBITED MUST CALL T6JOBCHK
#    EVERY 5 MILLISECONDS TO PROCESS A POSSIBLE WAITING T6RUPT BEFORE IT CAN BE HONORED BY THE HARDWARE.
#      (5.  PROGRAM JTLST, IN Q,R-AXES, HANDLES THE INPUT LIST.)
#
# T6JOBCHK CALLING SEQUENCE:
#    L  TC  T6JOBCHK
#    L+1  (RETURN)
#
# DOT6RUPT CALLING SEQUENCE:
#      DXCH  ARUPT    # T6RUPT LEAD IN AT LOCATION 4004.
#      EXTEND
#      DCA  T6ADR
#      DTCB
#
# SUBROUTINES CALLED:  DOT6RUPT CALLS T6JOBCHK.
#
# NORMAL EXIT MODES:  T6JOBCHK RETURNS TO L +1.
#      DOT6RUPT TRANSFERS CONTROL TO RESUME.
#
# ALARM/ABORT MODES:  NONE.
#
# INPUT:  TIME6    NXT6ADR    OUTPUT:    TIME6    NXT6ADR    CHANNEL 5
#    T6NEXT    T6NEXT +1      T6NEXT    T6NEXT +1  CHANNEL 6
#    T6FURTHA  T6FURTHA +1      T6FURTHA  T6FURTHA +1  BIT15/CH13
#
# DEBRIS:  T6JOBCHK CLOBBERS A.  DOT6RUPT CLOBBERS NOTHING.

    BLOCK  02
# Page 1404
    BANK  17
    SETLOC  DAPS2
    BANK
    EBANK=  T6NEXT
    COUNT*  $$/DAPT6

T6JOBCHK  CCS  TIME6    # CHECK TIME6 FOR WAITING T6RUPT:
    TC  Q    # NONE: CLOCK COUNTING DOWN.
    TC  CCSHOLE
    TC  T6JOBCHK +3

# CONTROL PASSES TO T6JOB ONLY WHEN C(TIME6) = -0 (I.E., WHEN A T6RUPT MUST BE PROCESSED).

T6JOB    CAF  POSMAX    # DISABLE CLOCK: NEEDED SINCE RUPT OCCURS
    EXTEND      # 1 DINC AFTER T6 = 77777. FOR 625 MUSECS
    WAND  CHAN13    # MUST NOT HAVE T6 = +0 WITH ENABLE SET

    CA  POSMAX
    ZL
    DXCH  T6FURTHA
    DXCH  T6NEXT
    LXCH  NXT6ADR
    TS  TIME6

    AD  PRIO37
    TS  A
    TCF  ENABLET6
    CA  POSMAX
    TS  TIME6
    TCF  GOCH56
ENABLET6  CA  BIT15
    EXTEND
    WOR  CHAN13
    CA  T6NEXT
    AD  PRIO37
    TS  A
    TCF  GOCH56
    CA  POSMAX
    TS  T6NEXT
GOCH56    INDEX  L
    TCF  WRITEP -1

    BLOCK  02
    SETLOC  FFTAG9
    BANK
    EBANK=  CDUXD
    COUNT*  $$/DAPT6

    CA  NEXTP
WRITEP    EXTEND
    WRITE  CHAN6
# Page 1405
    TC  Q

    CA  NEXTU
WRITEU    TS  L
    CS  00314OCT
    EXTEND
    RAND  CHAN5
    AD  L
    EXTEND
    WRITE  CHAN5
    TC  Q

    CA  NEXTV
WRITEV    TS  L
    CA  00314OCT
    TCF  -9D
00314OCT  OCT  00314

    BANK  17
    SETLOC  DAPS2
    BANK

    EBANK=  T6NEXT
    COUNT*  $$/DAPT6

DOT6RUPT  LXCH  BANKRUPT  # (INTERRUPT LEAD INS CONTINUED)
    EXTEND
    QXCH  QRUPT

    TC  T6JOBCHK  # CALL T6JOBCHK.

    TCF  RESUME    # END TIME6 INTERRUPT PROCESSOR.