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# Copyright: Public domain.
# Filename: EXECUTIVE.agc
# Purpose: Part of the source code for Colossus 2A, AKA Comanche 055.
# It is part of the source code for the Command Module's (CM)
# Apollo Guidance Computer (AGC), for Apollo 11.
# Assembler: yaYUL
# Contact: Ron Burkey <info@sandroid.org>.
# Website: www.ibiblio.org/apollo.
# Pages: 1208-1220
# Mod history: 2009-05-14 RSB Adapted from the Colossus249/ file of the
# same name, using Comanche055 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 055 of AGC program Comanche by NASA
# 2021113-051. 10:28 APR. 1, 1969
#
# This AGC program shall also be referred to as
# Colossus 2A
# Page 1208
BLOCK 02
# TO ENTER A JOB REQUEST REQUIRING NO VAC AREA:
COUNT 02/EXEC
NOVAC INHINT
AD FAKEPRET # LOC(MPAC +6) - LOC(QPRET)
TS NEWPRIO # PRIORITY OF NEW JOB + NOVAC C(FIXLOC)
EXTEND
INDEX Q # Q WILL BE UNDISTURBED THROUGHOUT.
DCA 0 # 2CADR OF JOB ENTERED.
DXCH NEWLOC
CAF EXECBANK
XCH FBANK
TS EXECTEM1
TCF NOVAC2 # ENTER EXECUTIVE BANK.
# TO ENTER A JOB REQUEST REQUIRING A VAC AREA - E.G., ALL (PARTIALLY) INTERPRETIVE JOBS.
FINDVAC INHINT
TS NEWPRIO
EXTEND
INDEX Q
DCA 0
SPVACIN DXCH NEWLOC
CAF EXECBANK
XCH FBANK
TCF FINDVAC2 # OFF TO EXECUTIVE SWITCHED-BANK.
# TO ENTER A FINDVAC WITH THE PRIORITY IN NEWPRIO TO THE 2CADR ARRIVING IN A AND L:
# USERS OF SPVAC MUST INHINT BEFORE STORING IN NEWPRIO.
SPVAC XCH Q
AD NEG2
XCH Q
TCF SPVACIN
# TO SUSPEND A BASIC JOB SO A HIGHER PRIORITY JOB MAY BE SERVICED:
CHANG1 LXCH Q
CAF EXECBANK
XCH BBANK
TCF CHANJOB
# TO SUSPEND AN INTERPRETIVE JOB:
CHANG2 CS LOC # NEGATIVE LOC SHOWS JOB = INTERPRETIVE.
# ITRACE (4) REFERS TO "CHANG2".
# Page 1209
TS L
+2 CAF EXECBANK
TS BBANK
TCF CHANJOB -1
# Page 1210
# TO VOLUNTARILY SUSPEND A JOB UNTIL THE COMPLETION OF SOME ANTICIPATED EVENT (I/O EVENT ETC.):
JOBSLEEP TS LOC
CAF EXECBANK
TS FBANK
TCF JOBSLP1
# TO AWAKEN A JOB PUT TO SLEEP IN THE ABOVE FASHION:
JOBWAKE INHINT
TS NEWLOC
CS TWO # EXIT IS VIA FINDVAC/NOVAC PROCEDURES.
ADS Q
CAF EXECBANK
XCH FBANK
TCF JOBWAKE2
# TO CHANGE THE PRIORITY OF A JOB CURRENTLY UNDER EXECUTION:
PRIOCHNG INHINT # NEW PRIORITY ARRIVES IN A. RETURNS TO
TS NEWPRIO # CALLER AS SOON AS NEW JOB PRIORITY IS
CAF EXECBANK # HIGHEST. PREPARE FOR POSSIBLE BASIC-
XCH BBANK # STYLE CHANGE-JOB.
TS BANKSET
CA Q
TCF PRIOCH2
# TO REMOVE A JOB FROM EXECUTIVE CONSIDERATIONS:
ENDOFJOB CAF EXECBANK
TS FBANK
TCF ENDJOB1
ENDFIND CA EXECTEM1 # RETURN TO CALLER AFTER JOB ENTRY
TS FBANK # COMPLETE.
TCF Q+2
EXECBANK CADR FINDVAC2
FAKEPRET ADRES MPAC -36D # LOC(MPAC +6) - LOC(QPRET)
# Page 1211
# LOCATE AN AVAILABLE VAC AREA.
BANK 01
COUNT 01/EXEC
FINDVAC2 TS EXECTEM1 # (SAVE CALLER'S BANK FIRST.)
CCS VAC1USE
TCF VACFOUND
CCS VAC2USE
TCF VACFOUND
CCS VAC3USE
TCF VACFOUND
CCS VAC4USE
TCF VACFOUND
CCS VAC5USE
TCF VACFOUND
TC BAILOUT
OCT 1201 # NO VAC AREAS.
VACFOUND AD TWO # RESERVE THIS VAC AREA BY STORING A ZERO
ZL # IN ITS VAC USE REGISTER AND STORE THE
INDEX A # ADDRESS OF THE FIRST WORD OF IT IN THE
LXCH 0 -1 # LOW NINE BITS OF THE PRIORITY WORD.
ADS NEWPRIO
NOVAC2 CAF ZERO # NOVAC ENTERS HERE. FIND A CORE SET.
TS LOCCTR
CAF NO.CORES # SEVEN SETS OF ELEVEN REGISTERS EACH.
NOVAC3 TS EXECTEM2
INDEX LOCCTR
CCS PRIORITY # EACH PRIORITY REGISTER CONTAINS -0 IF
TCF NEXTCORE # THE CORRESPONDING CORE SET IS AVAILABLE.
NO.CORES DEC 6
TCF NEXTCORE # AN ACTIVE JOB HAS A POSITIVE PRIORITY
# BUT A DORMANT JOB'S PRIORITY IS NEGATIVE
# Page 1212
CORFOUND CA NEWPRIO # SET THE PRIORITY OF THIS JOB IN THE CORE
INDEX LOCCTR # SET'S PRIORITY REGISTER AND SET THE
TS PRIORITY # JOB'S PUSH-DOWN POINTER AT THE BEGINNING
MASK LOW9 # OF THE WORK AREA AND OVERFLOW INDICATOR
INDEX LOCCTR
TS PUSHLOC # OFF TO PREPARE FOR INTERPRETIVE PROGRAMS
CCS LOCCTR # IF CORE SET ZERO IS BEING LOADED, SET UP
TCF SETLOC # OVFIND AND FIXLOC IMMEDIATELY.
TS OVFIND
CA PUSHLOC
TS FIXLOC
SPECTEST CCS NEWJOB # SEE IF ANY ACTIVE JOBS WAITING (RARE).
TCF SETLOC # MUST BE AWAKENED BUT UNCHANGED JOB.
TC CCSHOLE
TC CCSHOLE
TS NEWJOB # +0 SHOWS ACTIVE JOB ALREADY SET.
DXCH NEWLOC
DXCH LOC
TCF ENDFIND
SETLOC DXCH NEWLOC # SET UP THE LOCATION REGISTERS FOR THIS
INDEX LOCCTR
DXCH LOC
INDEX NEWJOB # THIS INDEX INSTRUCTION INSURES THAT THE
CS PRIORITY # HIGHEST ACTIVE PRIORITY WILL BE COMPARED
AD NEWPRIO # WITH THE NEW PRIORITY TO SEE IF NEWJOB
EXTEND # SHOULD BE SET TO SIGNAL A SWITCH.
BZMF ENDFIND
CA LOCCTR # LOCCTR IS LEFT SET AT THIS CORE SET IF
TS NEWJOB # THE CALLER WANTS TO LOAD ANY MPAC
TCF ENDFIND # REGISTERS, ETC.
NEXTCORE CAF COREINC
ADS LOCCTR
CCS EXECTEM2
TCF NOVAC3
TC BAILOUT # NO CORE SETS.
OCT 1202
# Page 1213
# THE FOLLOWING ROUTINE SWAPS CORE SET 0 WITH THAT WHOSE RELATIVE ADDRESS IS IN NEWJOB.
-2 LXCH LOC
-1 CAE BANKSET # BANKSET, NOT BBANK, HAS RIGHT CONTENTS.
CHANJOB INHINT
EXTEND
ROR SUPERBNK # PICK UP CURRENT SBANK FOR BBCON
XCH L # LOC IN A AND BBCON IN L.
+4 INDEX NEWJOB # SWAP LOC AND BANKSET.
DXCH LOC
DXCH LOC
CAE BANKSET
EXTEND
WRITE SUPERBNK # SET SBANK FOR NEW JOB.
DXCH MPAC # SWAP MULTI-PURPOSE ACCUMULATOR AREAS.
INDEX NEWJOB
DXCH MPAC
DXCH MPAC
DXCH MPAC +2
INDEX NEWJOB
DXCH MPAC +2
DXCH MPAC +2
DXCH MPAC +4
INDEX NEWJOB
DXCH MPAC +4
DXCH MPAC +4
DXCH MPAC +6
INDEX NEWJOB
DXCH MPAC +6
DXCH MPAC +6
CAF ZERO
XCH OVFIND # MAKE PUSHLOC NEGATIVE IF OVFIND NZ.
EXTEND
BZF +3
CS PUSHLOC
TS PUSHLOC
DXCH PUSHLOC
INDEX NEWJOB
DXCH PUSHLOC
DXCH PUSHLOC # SWAPS PUSHLOC AND PRIORITY.
CAF LOW9 # SET FIXLOC TO BASE OF VAC AREA.
MASK PRIORITY
TS FIXLOC
CCS PUSHLOC # SET OVERFLOW INDICATOR ACCORDING TO
CAF ZERO
TCF ENDPRCHG -1
# Page 1214
CS PUSHLOC
TS PUSHLOC
CAF ONE
XCH OVFIND
TS NEWJOB
ENDPRCHG RELINT
DXCH LOC # BASIC JOBS HAVE POSITIVE ADDRESSES, SO
EXTEND # DISPATCH WITH A DTCB.
BZMF +2 # IF INTERPRETIVE, SET UP EBANK, ETC.
DTCB
# Page 1215
COM # EPILOGUE TO JOB CHANGE FOR INTERPRETIVE
AD ONE
TS LOC # RESUME.
TCF INTRSM
# COMPLETE JOBSLEEP PREPARATIONS.
JOBSLP1 INHINT
CS PRIORITY # NNZ PRIORITY SHOWS JOB ASLEEP.
TS PRIORITY
CAF LOW7
MASK BBANK
EXTEND
ROR SUPERBNK # SAVE OLD SUPERBANK VALUE.
TS BANKSET
CS ZERO
JOBSLP2 TS BUF +1 # HOLDS - HIGHEST PRIORITY.
TCF EJSCAN # SCAN FOR HIGHEST PRIORITY ALA ENDOFJOB.
NUCHANG2 INHINT # QUICK... DONT LET NEWJOB CHANGE TO +0 .
CCS NEWJOB
TCF +3 # NEWJOB STILL PNZ
RELINT # NEWJOB HAS CHANGED TO +0. WAKE UP JOB
TCF ADVAN +2 # VIA NUDIRECT. (VERY RARE CASE.)
CAF TWO
EXTEND
WOR DSALMOUT # TURN ON ACTIVITY LIGHT
DXCH LOC # AND SAVE ADDRESS INFO FOR BENEFIT OF
TCF CHANJOB + 4 # POSSIBLE SLEEPING JOB.
# Page 1216
# TO WAKE UP A JOB, EACH CORE SET IS FOUND TO LOCATE ALL JOBS WHICH ARE ASLEEP. IF THE FCADR IN THE
# LOC REGISTER OF ANY SUCH JOB MATCHES THAT SUPPLIED BY THE CALLER, THAT JOB IS AWAKENED. IF NO JOB IS FOUND,
# LOCCTR IS SET TO -1 AND NO FURTHER ACTION TAKES PLACE.
JOBWAKE2 TS EXECTEM1
CAF ZERO # BEGIN CORE SET SCAN.
TS LOCCTR
CAF NO.CORES
JOBWAKE4 TS EXECTEM2
INDEX LOCCTR
CCS PRIORITY
TCF JOBWAKE3 # ACTIVE JOB - CHECK NEXT CORE SET.
COREINC DEC 12 # 12 REGISTERS PER CORE SET.
TCF WAKETEST # SLEEPING JOB - SEE IF CADR MATCHES.
JOBWAKE3 CAF COREINC
ADS LOCCTR
CCS EXECTEM2
TCF JOBWAKE4
CS ONE # EXIT IF SLEEPING JOB NOT FOUND.
TS LOCCTR
TCF ENDFIND
WAKETEST CS NEWLOC
INDEX LOCCTR
AD LOC
EXTEND
BZF +2 # IF MATCH.
TCF JOBWAKE3 # EXAMINE NEXT CORE SET IF NO MATCH.
INDEX LOCCTR # RE-COMPLEMENT PRIORITY TO SHOW JOB AWAKE
CS PRIORITY
TS NEWPRIO
INDEX LOCCTR
TS PRIORITY
CS FBANKMSK # MAKE UP THE 2CADR OF THE WAKE ADDRESS
MASK NEWLOC # USING THE CADR IN NEWLOC AND THE EBANK
AD 2K # HALF OF BBANK SAVED IN BANKSET.
XCH NEWLOC
MASK FBANKMSK
INDEX LOCCTR
AD BANKSET
TS NEWLOC +1
CCS LOCCTR # SPECIAL TREATMENT IF THIS JOB WAS
TCF SETLOC # ALREADY IN THE RUN (0) POSITION.
TCF SPECTEST
# Page 1217
# PRIORITY CHANGE. CHANGE THE CONTENTS OF PRIORITY AND SCAN FOR THE JOB OF HIGHEST PRIORITY.
PRIOCH2 TS LOC
CAF ZERO # SET FLAG TO TELL ENDJOB SCANNER IF THIS
TS BUF # JOB IS STILL HIGHEST PRIORITY.
CAF LOW9
MASK PRIORITY
AD NEWPRIO
TS PRIORITY
COM
TCF JOBSLP2 # AND TO EJSCAN.
# Page 1218
# RELEASE THIS CORE SET AND VAC AREA AND SCAN FOR THE JOB OF HIGHEST ACTIVE PRIORITY.
ENDJOB1 INHINT
CS ZERO
TS BUF +1
XCH PRIORITY
MASK LOW9
TS L
CS FAKEPRET
AD L
EXTEND
BZMF EJSCAN # NOVAC ENDOFJOB
CCS L
INDEX A
TS 0
EJSCAN CCS PRIORITY +12D
TC EJ1
TC CCSHOLE
TCF +1
CCS PRIORITY +24D # EXAMINE EACH PRIORITY REGISTER TO FIND
TC EJ1 # THE JOB OF HIGHEST ACTIVE PRIORITY.
TC CCSHOLE
TCF +1
CCS PRIORITY +36D
TC EJ1
-CCSPR -CCS PRIORITY
TCF +1
CCS PRIORITY +48D
TC EJ1
TC CCSHOLE
TCF +1
CCS PRIORITY +60D
TC EJ1
TC CCSHOLE
TCF +1
CCS PRIORITY +72D
TC EJ1
TC CCSHOLE
TCF +1
# Page 1219
# EVALUATE THE RESULTS OF THE SCAN.
CCS BUF +1 # SEE IF THERE ARE ANY ACTIVE JOBS WAITING
TC CCSHOLE
TC CCSHOLE
TCF +2
TCF DUMMYJOB
CCS BUF # BUF IS ZERO IF THIS IS A PRIOCHNG AND
TCF +2 # CHANGED PRIORITY IS STILL HIGHEST.
TCF ENDPRCHG -1
INDEX A # OTHERWISE, SET NEWJOB TO THE RELATIVE
CAF 0 -1 # ADDRESS OF THE NEW JOB'S CORE SET.
AD -CCSPR
TS NEWJOB
TCF CHANJOB -2
EJ1 TS BUF +2
AD BUF +1 # - OLD HIGH PRIORITY.
CCS A
CS BUF +2
TCF EJ2 # NEW HIGH PRIORITY.
NOOP
INDEX Q
TC 2 # PROCEED WITH SEARCH.
EJ2 TS BUF +1
EXTEND
QXCH BUF # FOR LOCATING CCS PRIORITY + X INSTR.
INDEX BUF
TC 2
# Page 1220
# IDLING AND COMPUTER ACTIVITY (GREEN) LIGHT MAINTENANCE. THE IDLING ROUTINE IS NOT A JOB IN ITSELF,
# BUT RATHER A SUBROUTINE OF THE EXECUTIVE.
EBANK= SELFRET # SELF-CHECK STORAGE IN EBANK.
DUMMYJOB CS ZERO # SET NEWJOB TO -0 FOR IDLING.
TS NEWJOB
RELINT
CS TWO # TURN OFF THE ACTIVITY LIGHT.
EXTEND
WAND DSALMOUT
ADVAN CCS NEWJOB # IS A NEWJOB ACTIVE ?
TCF NUCHANG2 # YES... ONE REQUIRING A CHANGE JOB.
CAF TWO # NEW JOB ALREADY IN POSITION FOR
TCF NUDIRECT # EXECUTION.
CA SELFRET
TS L # PUT RETURN ADDRESS IN L.
CAF SELFBANK
TCF SUPDXCHZ + 1 # AND DISPATCH JOB.
EBANK= SELFRET
SELFBANK BBCON SELFCHK
NUDIRECT EXTEND # TURN THE GREEN LIGHT BACK ON.
WOR DSALMOUT
DXCH LOC # JOBS STARTED IN THIS FASHION MUST BE
TCF SUPDXCHZ
BLOCK 2 # IN FIXED-FIXED SO OTHERS MAY USE.
COUNT 02/EXEC
# SUPDXCHZ - ROUTINE TO TRANSFER TO SUPERBANK.
# CALLING SEQUENCE
# TCF SUPDXCHZ # WITH 2CADR OF DESIRED LOCATION IN A + L.
SUPDXCHZ XCH L # BASIC.
+1 EXTEND
WRITE SUPERBNK
TS BBANK
TC L
NEG100 OCT 77677