swh:1:snp:92f3f585b9ae79620ad8c41a332d6329b31fd381
Tip revision: 078c79d8734a9ed2860303a7c1662004284fe853 authored by Ron Burkey on 07 August 2022, 15:04:04 UTC
Fixed a potential string-overflow bug in yaASM. Removed timestamps from
Fixed a potential string-overflow bug in yaASM. Removed timestamps from
Tip revision: 078c79d
THROTTLE_CONTROL.agc
### FILE="Main.annotation"
## Copyright: Public domain.
## Filename: THROTTLE_CONTROL.agc
## Purpose: A module for revision 0 of BURST120 (Sunburst). It
## is part of the source code for the Lunar Module's
## (LM) Apollo Guidance Computer (AGC) for Apollo 5.
## Assembler: yaYUL
## Contact: Ron Burkey <info@sandroid.org>.
## Website: www.ibiblio.org/apollo/index.html
## Mod history: 2016-09-30 RSB Created draft version.
## 2016-10-30 MAS Transcribed.
## 2016-11-02 RSB Typo.
## 2016-12-06 RSB Comment-proofing via octopus/ProoferComments;
## changes were made.
## Page 849
# THROTTLE CONTROL CAN BE USED IN EITHER OF TWO MODES: IN "PERCENTAGE MODE" (WHEN A CERTAIN FRACTION OF
# MAXIMUM THRUST IS DESIRED) AND IN "ACCELERATION MODE" (WHEN THE THRUST DESIRED IS THAT CORRESPONDING TO A
# SPECIFIED ACCELERATION).
# PERCENTAGE MODE ACCELERATION MODE
# THE FRACTION OF MAXIMUM THRUST (NOMINALLY DESIRED ACCELERATION, IN DOUBLE PRECISION,
# 10500 POUNDS) DESIRED, IN SINGLE PRECISION, IS IN UNITS OF 2(-5) M/CS/CS, IS PLACED IN /ACF/.
# PLACED IN PCNTF. ENTRY IS VIA A DTCB AN THE ENTRY IS VIA A DTCB ON THE 2CADR OF THROTCON.
# 2CADR OF PCNTFMAX. THE ROUTINE BEGINNING AT THE ROUTINE BEGINNING AT THROTCON SETS UP A JOB -
# PCNTFMAX SETS UP A JOB - PCNTJOB - AND RETURNS ACCLJOB - AND RETURNS TO THE USER (AT THE
# TO THE USER (AT THE INSTRUCTION IMMEDIATELY INSTRUCTION FOLLOWING THE DTCB).
# FOLLOWING THE DTCB).
# ACCLJOB, AFTER A RESTART PROTECT,
# PCNTJOB, AFTER A RESTART PROTECT, COMPUTES DESIRED ACCELERATION, FC = /ACF/ MASS,
# TURNS OFF THE TRIM GIMBAL, SETS UP A WAITLIST SCALED AT ABOUT 2.7 POUNDS PER BIT.
# TASK (DESCRIBED LOCALLY), COMPUTES THRUST DESIRED,
# FC = PCNTF FMAX, SCALED AT ABOUT 2.7 POUNDS PER BIT, (NOTE THAT IN THE ACCELERATION MODE THE TRIM
# AND TCF'S AROUND THE COMMENCEMENT OF ACCLJOB TO GIMBAL IS NOT TURNED OFF; IT IS ASSUMED TO BE OFF
# FOLDCALC. BY THE TIME THROTTLE CHANGES ARE COMMANDED.
# FOLDCALC BEGINS BY COMPUTING PRESENT THRUST, FOLD = MASS /AF/, SCALED AS IS FC. NEXT, SINCE /AF/ IS
# MERELY AN "AVERAGE" OF THE THROTTLE LEVELS OF THE PRECEEDING PIPA INTERVAL, FOLD IS WEIGHTED BY FWEIGHT, A
# FUNCTION OF THE PRECEEDING THROTTLE COMMAND (DESCRIBED LOCALLY). TO PRECLUDE A SPURIOUS WEIGHTING THAT WOULD
# OTHERWISE OCCUR, FWEIGHT IS ZEROED 1.95 SECONDS AFTER EVERY PERCENTAGE MODE THROTTLING.
# NEXT, TO COMPENSATE FOR THE DIFFERENTIAL BETWEEN BITS FOR MAXIMUM THRUST AND BITS FOR FULL THROTTLE, THE
# NUMBER FOLD - FODD IS COMPUTED AND SET INTO PIFPSET WHENEVER FCOLD INDICATES THE THROTTLE IS AT MAXIMUM.
# SINCE PIFPSET IS USED, RATHER THAN PIF, PIF STILL REFLECTS ACCURATELY THE ACTUAL THRUST CHANGE AND FWEIGHT IS
# COMPUTED PROPERLY.
# NEXT COMES IS-IT-ON. HERE THE ENGINE-OFF BIT (14 OF CHANNEL 11) IS QUERIED; IF THE ENGINE IS OFF
# FCOLD, THE SINGLE PRECISION HISTORY REGISTER, IS SET TO 10% FMAX AND PIFPSET, A PRESETTING ADDED TO PIF AT
# THE LAST MOMENT, IS SET TO -10% FMAX TO COMPENSATE FOR THE ASSUMED SETTING OF THE MANUAL THROTTLE.
# THE SERIES OF DECISIONS BEGINNING AT WHERETO CAUSES THE THROTTLE TO REACT TO USERS' DESIRES IN THE
# MANNER DESCRIBED BY FIGURE 5.3-5 OF THE FLIGHT 206 GSOP. WHERETO PROCEEDS (OR BRANCHES) TO FLATOUT (IF THE
# THROTTLE LEVEL ASKED FOR IS IN THE FORBIDDEN REGION) OR TO DOPIF. FLATOUT RESETS FC TO 94% FMAX, SETS FEXTRA
# (A BOOST GIVEN TO THE THROTTLE TO KEEP IT JAMMED AGAINST ITS STOPS) INTO PIFPSET, AND PROCEEDS TO DOPIF.
# DOPIF, AFTER A "TYPE C" RESTART PROTECT (NECESSITATED BY THE FACT THAT FCOLD AND PIF, USED EARLIER, ARE
# ABOUT TO BE MODIFIED), SETS FCOLD = FC, COMPUTES PIF (PULSE INCREMENT FOR ACCELERATION) = FC - FOLD, AND, AS
# IT PROCEEDS TO DOIT, HAS THIS NUMBER PLUS PIFPSET IN A & L.
# DOIT DOES IT. IT TS'S INTO THRUST, THE CHANNEL (55) LEADING TO DECA, THE THROTTLE-AGC INTERFACE
# CIRCUIT, AND SETS BIT 4 IN CHANNEL 11, THE SIGNAL FOR THRUST TO BE COUNTED DOWN (AT 3200 PPS). FINALLY,
# FWEIGHT = F(PIF) IS COMPUTED FOR USE NEXT PASS.
# AFTER ANOTHER RESTART PROTECT A TCF ENDOFJOB ENDS THROTTLE CONTROL.
## Page 850
BANK 30
EBANK= ETHROT
# ***************
# * SUBROUTINES *
# ***************
# THIS SUBROUTINE MULTIPLIES ACCELERATION
# (ARRIVING IN A AND L) BY MASS AND LEAVES
# FORCE (THRUST) IN A & L, SCALED AT ABOUT
# 2.7 POUNDS PER BIT.
MASSMULT EXTEND
QXCH BUF # PRESERVING RETURN ADDRESS
DXCH MPAC
TC DMP # LEAVES ODDLY SCALED FORCE IN MPAC
ADRES MASS
TC DMP # LEAVES PROPERLY SCALED FORCE IN MPAC
ADRES SCALEFAC
DXCH MPAC +1 # LOADING FORCE INTO A AND L
TC BUF # IN WHICH Q WAS STORED
# THIS TASK WILL BE EXECUTED 1.95 SECONDS
# AFTER PERCENTAGE MODE THROTTLING.
PCNTOVER CS ZERO
TS FWEIGHT # SCHEME WILL WORK PROPERLY NEXT PASS
TS FWEIGHT +1
ZL # -0 STILL IN A
DXCH -PHASE1
TCF TASKOVER
## The character used for separation below, and throughout the rest of this section, was actually a small
## box, similar to the unicode white square (U+25A1). All occurrences have been replaced with the ASCII =.
# ========================================================================
THROTDT DEC +195
PGUID DEC +200
# ========================================================================
## Page 851
# ***********
# * ENTRIES *
# ***********
# THIS ENTRY SETS UP A JOB WHICH WILL
# DELIVER A SPECIFIED FRACTION OF MAXIMUM
# THRUST. THIS FRACTION ARRIVES (SP) IN
# REGISTER PCNTF.
PCNTFMAX DXCH RTNHOLD # RETAINING 2CADR FOR RETURN TO USER
CAF PRIO25
INHINT
TC NOVAC
EBANK= ETHROT
2CADR PCNTJOB
RELINT
TCF AWAY
# NORMAL ENTRY FROM GUIDANCE EQUATIONS:
# THE JOB SET UP HERE DELIVERS A THRUST
# CORRESPONDING TO THE DESIRED MAGNITUDE
# OF THRUST-ACCELERATION. THIS VALUE
# ARRIVES (DP) IN /ACF/, SCALED IN UNITS
# OF 2(-5) M/CS/CS.
THROTCON DXCH RTNHOLD # RETAINING 2CADR FOR RETURN TO USER
CAF PRIO30
INHINT
TC NOVAC
EBANK= ETHROT
2CADR ACCLJOB
RELINT
# THIS RETURN IS COMMON TO BOTH ENTRIES.
AWAY DXCH RTNHOLD
DTCB
## Page 852
# ***************
# * COMPUTATION *
# ***************
PCNTJOB INHINT # SINCE THROTTLING IS ABOUT TO COMMENCE.
CAF THROTDT # SET UP A TASK TO ZERO FWEIGHT IN 2 SECS
TC WAITLIST
EBANK= ETHROT
2CADR PCNTOVER
TC 2PHSCHNG
OCT 40031 # 1.3 SPOT FOR PCNTOVER
OCT 05024
OCT 25000
EXTEND
DCS -FMAX
DXCH MPAC
CA PCNTF
TC SHORTMP
DXCH MPAC # LOADING
DXCH FC # STORING
CA ZERO # ZEROING FWEIGHT SINCE IT'S UNKNOWN
TS FWEIGHT
TS FWEIGHT +1
TCF FOLDCALC
## In the following line, and the corresponding line a few lines below it,
## it's unclear what the characters printed are supposed to be. In the
## hardcopy, they appear as small rectangular boxes.
# ########################################################################
SCALEFAC 2DEC +51.946987 B-14 # QUASI-NEWTONS TO PULSE UNITS
2.PG.FRT DEC 12800 # TWICE PGUID TIME PULSE RATE
-LOCRIT DEC -2019 # THE LOWER MID-SCALE CRITERION
FEXTRA = -LOCRIT
+FLOW DEC +438 # MINIMUM ATTAINABLE THRUST
# ########################################################################
ACCLJOB TC PHASCHNG
OCT 05024
OCT 30000
EXTEND
DCA /ACF/
TC MASSMULT
DXCH FC # FC = MASS /ACF/, SCALED
## Page 853
FOLDCALC EXTEND
DCA /AF/
TC MASSMULT
DXCH FOLD # FOLD = MASS /AF/, SCALED
EXTEND
DCA FWEIGHT # WEIGHTING FOLD BY FWEIGHT
DAS FOLD # AS COMPUTED LAST PASS
# IF THE THROTTLE IS AT MAXIMUM, THE
# QUANTITY -(FODD-FOLD) IS COMPUTED AND
# PUT INTO PIFPSET TO COMPENSATE FOR THE
# DIFFERENCE BETWEEN THE NUMBER OF BITS
# (I.E. PULSES) CORRESPONDING TO 100%
# THROTTLE (FODD) AND THE NUMBER CORRES-
# PONDING TO ACTUAL THRUST (FOLD). THIS
# COMPENSATION IS NEEDED IF THE THROTTLE
# RETURNS TO THE THROTTLEABLE REGION THIS
# PASS. IF IT DOES NOT, PIFPSET IS RESET
# IN FLATOUT.
FCOMPSET CS ZERO
TS PIFPSET
CS +HICRIT
AD FCOLD
EXTEND
BZMF IS-IT-ON # BRANCH IF FCOLD < HICRIT, OTHERWISE
CS +FODD # COMPUTE THE COMPENSATION NUMBER
AD FOLD
TS PIFPSET
# THIS ROUTINE CHECKS THE ENGINE-OFF BIT.
# IF THE ENGINE IS OFF, FCOLD IS SET TO
# 10 PERCENT FMAX, AND, SINCE /AF/ DOES
# NOT REFLECT THE SETTING OF THE MANUAL
# THROTTLE, THAT SETTING (AROUND 12%) IS
# PLACED NEGATIVELY IN PIFPSET.
IS-IT-ON CS FLAGWRD1
MASK ENGINBIT
EXTEND
BZF WHERETO # BRANCH HERE IF ENGINE IS ON
CA +FLOW
TS FCOLD # SETTING FCOLD
CS +FLOW
TS PIFPSET
## Page 854
# ************
# * DECISION *
# ************
# THIS LOGIC DETERMINES THROTTLING IN THE
# REGION 10% - 94%. THE MANUAL THROTTLE,
# SET TO MINIMUM BY MISSION PHASE PROGRMS,
# PROVIDES THE LOWER BOUND; A STOP IN THE
# ENGINE ITSELF PROVIDES THE UPPER.
WHERETO CA FC
AD -LOCRIT
EXTEND
BZMF DOPIF # BRANCH IF FC < LOCRIT
CS FC
AD +HICRIT
EXTEND
BZMF FLATOUT # BRANCH IF FC > OR = HICRIT
CS +HICRIT
AD FCOLD
EXTEND
BZMF DOPIF # BRANCH IF FCOLD < OR = HICRIT,
# OTHERWISE PROCEED TO FLATOUT
## Page 855
# *************
# * EXECUTION *
# *************
FLATOUT EXTEND
DCA +FHIGH
DXCH FC
CS FEXTRA
TS PIFPSET
DOPIF TC PHASCHNG
OCT 04024 # ?
EXTEND
DCA FC
TS FCOLD # HISTORY
DXCH PIF
EXTEND
DCS FOLD
DAS PIF # PIF = FC - FOLD
TC DAPLOGIC
DAPLRETN CA PIF
AD PIFPSET # ADD IN PIFPSET, NOT CHANGING PIF
DOIT TS THRUST
TC PHASCHNG
OCT 04024
CAF BIT4
EXTEND
WOR 14 # AND THE ENGINE DOES THE REST...
## What we show as a percent-sign below ("WOULD THAT IT WERE%") was really a 1/2 symbol (½)
## in the original hardcopy.
# SINCE /AF/ IS NOT AN INSTANTANEOUS
# ACCELERATION (WOULD THAT IT WERE%) BUT
# RATHER AN "AVERAGE" OF THE ACCELERATION
# LEVELS OF THE LAST PIPA INTERVAL, AND
# SINCE FOLD IS COMPUTED DIRECTLY FROM
# /AF/, FOLD IN ORDER TO CORRESPOND TO THE
# ACTUAL THRUST LEVEL AT THE END OF THE
# INTERVAL MUST BE WEIGHTED BY
# PIF PPROCES PIF /PIF/
# FWEIGHT = ----------- + ------------- ,
# PGUID 2 PGUID FRATE
# WHERE PPROCES IS THE TIME BETWEEN PIPA
# READING AND THE START OF THROTTLING,
# PGUID IS THE GUIDANCE PERIOD (2 SECONDS)
## Page 856
# AND FRATE IS THE THROTTLING RATE (SOME
# 3200 UNITS PER SECOND). HERE FWEIGHT
# IS COMPUTED FOR USE NEXT PASS.
EXTEND
DCA TIME2
DXCH MPAC
EXTEND
DCS PIPTIME
DAS MPAC
CA PGUID
XCH MPAC +1
MASK POSMAX # IN CASE THAT LOUSY SIGN BIT IS SET
EXTEND
DV MPAC +1 # WHICH CONTAINS PGUID
EXTEND
MP PIF
DXCH FWEIGHT # FWEIGHT = (PPROCES/PGUID)PIF, SO FAR...
CA 2.PG.FRT
XCH MPAC # TO BE USED AS A DIVISOR LATER
CCS PIF
AD ONE
TCF +2
AD ONE
EXTEND # AT THIS POINT HAVE /PIF/ IN A
MP PIF
EXTEND
DV MPAC # WHICH CONTAINS 2.PG.FRT
LXCH 7
DAS FWEIGHT
TC PHASCHNG
OCT 00004
TCF ENDOFJOB
## Page 857
# *************
# * CONSTANTS *
# *************
# CONSTANTS FOR DECISION
+FODD DEC +3866 B-14 # THIS MUCH SATURATES THROTTLE
-FMAX 2DEC -3882 B-14 # NOMINAL MAX THRUST IN BIT UNITS
+FHIGH 2DEC +3648 B-14 # MAX ATTAINABLE THRUST, UNERODED
+HICRIT DEC +2252 B-14 # THE HIGHER MID-SCALE CRITERION
## In the following line, and the corresponding line a few lines below it,
## it's unclear what the characters printed are supposed to be. In the
## hardcopy, they appear as small rectangular boxes.
# ########################################################################
# SINCE BETWEEN REVISION 113 AND 114 IT WAS NECESSARY TO PRESERVE THE
# LOCATIONS IN MEMORY OF LABELS ADDRESSED FROM OTHER BANKS (SINCE THE ROPE
# IS ALREADY UNDER CONSTRUCTION) CERTAIN CONSTANTS WERE REMOVED FROM THIS
# SECTION FOR USE AS FILLER ELSEWHERE. THESE ARE -LOCRIT, +FLOW,
# SCALEFAC, FEXTRA, THROTDT, PGUID, AND 2.PG.FRT.
# ########################################################################
# IF THE TRIM GIMBAL IS TURNED OFF BY
# THE THROTTLE, THIS TASK WILL REENABLE IT
# ABOUT 2 SECONDS LATER.
THROTOVR TC FLAG2DWN
OCT 00010
CS ZERO
ZL
DXCH -PHASE1
TCF TASKOVER
DAPLOGIC CA PIF
EXTEND
BZMF +2
COM
AD HITHRESH
EXTEND
BZMF JETSET # BRANCH IF /PIF/ > OR = HITHRESH
CA FOLD
DOUBLE
TS BUF
## Page 858
CA FC
EXTEND
DV BUF # WHERE TWICE FOLD WAS STORED
TS BUF
CA EBANK6
TS EBANK
EBANK= D2CDUYFL
CA BUF
EXTEND
MP D2CDUYFL
DOUBLE
XCH D2CDUYFL
CA BUF
EXTEND
MP D2CDUZFL
DOUBLE
XCH D2CDUZFL
CA EBANK5
TS EBANK
EBANK= ETHROT
TCF DAPLRETN
JETSET INHINT
CS DAPBOOLS # INHIBIT USE OF TRIM GIMBAL
MASK USEQRJTS
ADS DAPBOOLS
CA THROTDT # SET UP TASK TO REMOVE THE INHIBITION
TC WAITLIST # CREATED BELOW
EBANK= ETHROT
2CADR THROTOVR
TC FLAG2UP # INHIBIT THE GIMBLMON FROM REACTIVATING
OCT 00010 # THE GIMBAL
TC PHASCHNG
OCT 47011
DEC 195
EBANK= ETHROT
2CADR THROTOVR
TCF DAPLRETN
HITHRESH DEC +194 # ABOUT 5 % OF NOMINAL MAXIMUM THRUST
