THROTTLE_CONTROL.agc
### FILE="Main.annotation"
## Copyright: Public domain.
## Filename: THROTTLE_CONTROL.agc
## Purpose: A section of Sunburst revision 37, or Shepatin revision 0.
## It is part of an early development version of the software
## for Apollo Guidance Computer (AGC) on the unmanned Lunar
## Module (LM) flight Apollo 5. Sunburst 37 was the program
## upon which Don Eyles's offline development program Shepatin
## was based; the listing herein transcribed was actually for
## the equivalent revision 0 of Shepatin.
## This file is intended to be a faithful transcription, except
## that the code format has been changed to conform to the
## requirements of the yaYUL assembler rather than the
## original YUL assembler.
## Reference: pp. 795-801
## Assembler: yaYUL
## Contact: Ron Burkey <info@sandroid.org>.
## Website: www.ibiblio.org/apollo/index.html
## Mod history: 2017-05-24 MAS Created from Sunburst 120.
## 2017-06-09 HG Transcribed
## 2017-06-15 HG Fix operator DXCH -> DAS
## 2017-06-23 RSB Proofed comment text with
## octopus/ProoferComments.
## Page 795
BANK 30
EBANK= ETHROT
# INPUTS TO THROTTLE CONTROL ARE /A/ AND /AFC/, ACCELERATIONS PRESENT
# AND DESIRED, SCALED IN UNITS OF 2(-5) M/CS/CS, AND MASS IN UNITS OF
# 2(15) KILOGRAMS.
# THIS PROGRAM CAUSES THE THROTTLE TO RESPOND TO ACCELERATION COMMANDS
# IN THE MANNER DESCRIBED BY FIGURE 5.3-5 OF THE FLIGHT 206 GSOP.
# ***************
# * SUBROUTINES *
# ***************
# THIS SUBROUTINE MULTIPLIES ACCELERATION
# (ARRIVING IN A AND L) BY MASS AND LEAVES
# FORCE (THRUST) IN A AND L, SCALED AT
# ABOUT 3.3 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
## Page 796
# ***********
# * 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/.
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 797
# ***************
# * COMPUTATION *
# ***************
PCNTJOB TC PHASCHNG
OCT 04024 # ?
EXTEND
DCS -FMAX
DXCH MPAC
CA PCNTF
TC SHORTMP
DXCH MPAC # LOADING
DXCH FC # STORING
TCF FOLDCALC
ACCLJOB = FCCALC
FCCALC TC PHASCHNG
OCT 04024 # ?
EXTEND
DCA /ACF/
TC MASSMULT
DXCH FC # FC = MASS /ACF/, SCALED
FOLDCALC EXTEND
DCA /AF/
TC MASSMULT
DXCH FOLD # FOLD = MASS /AF/, SCALED
# AFTER FIRST ZEROING PIF, THIS ROUTINE
# CHECKS THE ENGINE-OFF BIT. IF THE
# ENGINE PROVES TO BE OFF FCOLD IS SET TO
# 10 PERCENT FMAX, AND, SINCE /AF/ DOES
# NOT REFLECT THE 10 PERCENT SETTING OF
# THE HAND THROTTLE, -10 PERCENT FMAX
# IS ADDED INTO PIF.
NEXTNEXT CA ZERO
TS PIF
TS PIF +1
CA BIT14
## Page 798
EXTEND
RAND 11
EXTEND
BZF WHERETO # BRANCH HERE IF ENGINE IS ON
CS -.1FMAX
TS FCOLD # SETTING FCOLD
CA -.1FMAX
TS PIF # SETTING PIF
## Page 799
# ************
# * DECISION *
# ************
WHERETO CA FC
AD -.1FMAX
EXTEND
BZMF TIPTOE # BRANCH IF FC < OR = 10 PERCENT FMAX
CA FC
AD -.52FMAX
EXTEND
BZMF DOPIF # BRANCH IF FC < 52 PERCENT
CS FC
AD .58FMAX
EXTEND
BZMF FLATOUT # BRANCH IF FC > OR = 58 PERCENT FMAX,
CA FCOLD # OTHERWISE, TEST FCOLD
AD -FMAX
EXTEND
BZMF DOPIF # BRANCH IF FCOLD < OR = 100 PERCENT FMAX,
# OTHERWISE (IN WHICH CASE FCOLD=HIGHT)
# PROCEED TO FLATOUT
## Page 800
# *************
# * EXECUTION *
# *************
FLATOUT CA 2FMAX
TS FC
TCF DOPIF
TIPTOE EXTEND
DCS -.1FMAX
DXCH FC
DOPIF TC PHASCHNG
OCT 04024 # ?
EXTEND
DCA FC
TS FCOLD # HISTORY
DAS PIF # OKAY SINCE PIF PREVIOUSLY WAS ZEROED
EXTEND
DCS FOLD
DAS PIF # PIF = FC - FOLD + PRESETTING (IF ANY)
CA PIF
DOIT TS THRUST
CAF BIT4
EXTEND
WOR 14 # AND THE ENGINE DOES THE REST...
TC PHASCHNG
OCT 04024 # GROUP NUMBER NOT FINALIZED
TCF ENDOFJOB
## Page 801
# *************
# * CONSTANTS *
# *************
# CONSTANTS FOR DECISION
2FMAX DEC +6400 B-14 # 200% FMAX
-FMAX 2DEC +3200 B-14 # 100 % FMAX, NEGATIVE
.58FMAX DEC +1856 B-14 # 58 % FMAX
-.52FMAX DEC -1662 B-14 # JUST UNDER 52 % FMAX, NEGATIVE
-.1FMAX 2DEC -320 B-14 # 10 % FMAX. NEGATIVE
SCALEFAC 2DEC 46.835424 B-14 # ABOUT 10000/(3 16 4.4482) B-14
