SECOND_DPS_GUIDANCE.agc
### FILE="Main.annotation"
## Copyright: Public domain.
## Filename: SECOND_DPS_GUIDANCE.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. 814-850
## 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.
## 2017-06-13 HG Transcribed
## 2017-06-15 HG Fix interpretive operand /AFC/ -> /ACF/
## 2017-06-17 MAS Added a workaround for yaYUL calculating a
## fractional number off by one.
## 2017-06-23 RSB Proofed comment text with
## octopus/ProoferComments.
## 2021-05-30 ABS 2DEC* -> DEC for non extended address fields.
## Page 814
# PROGRAM NAME - SECOND DPS GUIDANCE
# MOD NO. - 0
# MODIFICATION BY - KLUMPP AND EYLES
# FUNCTIONAL DESCRIPTION -
# THERE ARE TWO MODES OF OPERATION OF THE SECOND DPS GUIDANCE PROGRAM (2DPS). PRIOR TO THE IGNITION
# SEQUENCE 2DPS IS OPERATED IN THE PRE-IGNITION MODE FOR THE PURPOSE OF PROVIDING, FOR THE IGNITION
# SEQUENCE, THE TIME OF INITIATION AND THE DIRECTION OF THRUST. IMMEDIATELY AFTER THE IGNITION SEQUENCE
# IS COMPLETED, INCLUDING THE COMMAND OF MAXIMUM THRUST, 2DPS IS ENGAGED IN THE THRUSTING MODE FOR THE
# PURPOSE OF PROVIDING THRUST ACCELERATION MAGNITUDE AND DIRECTION COMMANDS NECESSARY TO CONDUCT THE
# SIMULATED POWERED LANDING MANEUVER.
# PRIOR TO LAUNCH, ERASABLE MEMORY MUST BE LOADED WITH THE SEMI-UNIT NORMAL TO THE PLANE OF THE
# REQUIRED ORBIT CPT6/2, AND DATA WHICH INDIRECTLY SPECIFICIES THE NOMINAL IGNITION TIME TIGNOM. THESE
# DATA MAY BE ADJUSTED, AS A GROUP, VIA THE UPLINK, UNTIL 200 SECONDS PRIOR TO THE TIGNOM IMPLIED BY THE
# PRE-LAUNCH LOAD OR IMPLIED BY THE UPLINK DATA, WHICHEVER IS EARLIER. A DESCRIPTION OF THE METHOD OF
# UPDATING TIGNOM IS IN THE PROVINCE OF THE MISSION CONTROL PROGRAM (MCP) MISSION PHASE 11 -
# DPS2/FITH/APS1. THE TARGETING IS CONTROLLED BY THE SEMI-UNIT VECTOR CPT6/2 AS DESCRIBED IN THE 206 GSOP.
# AT APPROXIMATELY 180 SECONDS PRIOR TO TIGNOM, THE MCP ENGAGES 2DPS IN THE PRE-IGNITION MODE BY
# PROVIDING AN EXTRAPOLATED TIME AND STATE IN THE REGISTERS TET, RIGNTION, VIGNTION, AND TRANSFERRING
# CONTROL TO LOCATION PREBURN IN 2DPS. THIS TIME AND STATE ARE AT APPROXIMATELY 50 SECONDS PRIOR TO
# TIGNOM. (THE NAMES RIGNTION, VIGNTION, CHOSEN TO INDICATE USAGE WITH OTHER GUIDANCE PROGRAMS, ARE
# MISLEADING WITH 2DPS IN THAT THE EXTRAPOLATED STATE PROVIDED IN THESE REGISTERS IS NOT THAT EXPECTED AT
# IGNITION BUT RATHER AT 50 SECONDS PRIOR TO IGNITION.) 2DPS TRANSFERS THE CONTENTS OF TET TO PIPTIME
# AND CALLS SUBROUTINE VPATCHER WHICH TRANSFERS THE STATE TO RN, VN AND INITIALIZES FOR CALCRVG.
# USING CALCRVG AS A SUBROUTINE, AND INTERNAL SUBROUTINES IGNITN1 AND IGNITN2, 2DPS MOVES THE TIME AND
# STATE FORWARD TO A TIME GREATER THAN OR EQUAL TO TULLG-6 SECONDS AND LESS THAN OR EQUAL TO TULLG-3.8 SECONDS,
# LEAVING THIS CONSISTENT SET IN PIPTIME, RN, VN, WHERE TULLG IS THE PRECISE TIME FOR ULLAGE TO BE INITIATED
# AND IS LEFT IN THE REGISTER OF THAT NAME. 2DPS LEAVES A SEMI-UNIT VECTOR IN THE DIRECTION IN WHICH
# THRUST IS TO BE COMMANDED DURING THE IGNITION SEQUENCE IN THE REGISTER POINTVSM AND BRANCHES TO
# LOCATION RETPREB IN THE MISSION CONTROL PROGRAM.
# USING THE DATA LEFT BY THE PRE-IGNITION MODE OF 2DPS, THE MCP ENGAGES KALCMANU TO PROPERLY
# ORIENT THE SPACECRAFT FOR THE IGNITION SEQUENCE, AND ISSUES THE WAITLIST CALLS WHICH CAUSE THE
# READACCS, SERVICER, PGNCSMON LOOP TO BE ESTABLISHED (WITH 2DPS NOT IN THE LOOP) AND PRODUCE ULLAGE,
# ENGINE IGNITION, AND FINALLY MAXIMUM THRUST. IMMEDIATELY AFTER MAXIMUM THRUST IS COMMANDED, THE MCP
# PLACES THE 2BCADR OF BURN (EBANK= E2DPS) IN THE AVGEXIT WHICH CAUSES 2DPS TO BE ADDED TO THE READACCS,
# SERVICER, PGNCSMON LOOP IMMEDIATELY FOLLOWING CALCRVG.
# WHEN CONTROL IS GIVEN TO 2DPS WITH THE 2BCADR OF BURN IN AVGEXIT, 2DPS OPERATES IN THE THRUSTING
# MODE. IT GENERATES THE SEQUENCING REQUIRED TO CONDUCT THE SIMULATED POWERED LANDING MANEUVER AND ISSUES
# THE THRUST ACCELERATION MAGNITUDE AND DIRECTION COMMANDS.
# 2DPS GENERATES THE SEQUENCING BY INCREMENTING THE HIGH ORDER PART OF AVGEXIT, BY AN APPROPRIATE
# INTEGER, TO ACCOMPLISH EACH CHANGE OF 2DPS PHASE. THE INCREMENTING OF AVGEXIT CAUSES, ON THE SUBSEQUENT
## Page 815
# PASS THROUGH 2DPS, CONTROL TO BEGIN AT A NEW POINT IN THE SECOND DPS FLITE SEQUENCE TABLE, AND
# CONSEQUENTLY THE CORRESPONDING 2DPS MODING TO BE ESTABLISHED.
# 2DPS GENERATES THE THRUST ACCELERATION MAGNITUDE AND DIRECTION COMMANDS ON THE BASIS OF THE
# CONTENTS OF PIPTIME, RN, VN, AT THE BEGINNING OF THE PASS. TO ISSUE THE THRUST ACCELERATION DIRECTION
# COMMAND, 2DPS PLACES A SEMI-UNIT VECTOR IN THE REQUIRED DIRECTION IN THE REGISTER AXISD AND CALLS
# FINDCDUD AS A SUBROUTINE. TO ISSUE THE MAGNITUDE COMMAND, 2DPS PLACES THE REQUIRED MAGNITUDE IN THE
# REGISTER /ACF/ AND CALLS THROTCON AS A SUBROUTINE.
# BEFORE BUT NOT INCLUDING THE LAST PASS, 2DPS TERMINATES THE JOB PERIODICALLY STARTED BY READACCS
# BY BRANCHING TO ENDOFJOB.
# ON THE LAST PASS 2DPS PLACES THE SEMI-UNIT VECTOR ALONG THE NORMAL TO THE DESIRED ORBITAL PLANE,
# CPT6/2, IN THE REGISTER AXISD, CALLS FINDCDUD, AND BRANCHES TO LOCATION RETBURN IN THE MCP. THE MCP
# REMOVES 2DPS FROM THE READACCS, SERVICER, PGNCSMON LOOP AND ISSUES THE WAITLIST CALLS WHICH PRODUCE THE
# RANDOM THROTTLING. THE MCP DOES NOT CHANGE THE CONTENTS OF AXISD SUPPLIED BY 2DPS. CONSEQUENTLY THE
# THRUST ACCELERATION DURING RANDOM THROTTLING IS NORMAL TO THE ORBITAL PLANE.
## Page 816
# INTERFACE SPECIFICATIONS -
# SPECIFICATION PRE-IGNITION MODE THRUSTING MODE
# CALLING SEQUENCE - DTCB TO PREBURN DTCB TO BURN
# (EBANK= E2DPS) (EBANK= E2DPS)
# NORMAL EXITS - DTCB TO LOCATION PRIOR TO LAST PASS -
# RETPREB (EBANK= TC TO ENDOFJOB
# EMP11JOB) IN MISSION
# CONTROL PROGRAM. LAST PASS -
# DTCB TO LOCATION
# RETBURN (EBANK=
# EMP11JOB) IN MISSION
# CONTROL PROGRAM
# ALARM OR ABORT EXITS - NONE NONE
# ERASABLE
# INITIALIZATION - CPT6/2 (IMU COORDS) 2BCADR OF BURN
# OTHER INITIALIZATION (EBANK= E2DPS) MUST
# DONE INTERNALLY BE IN AVGEXIT. OTHER
# INITIALIZATION DONE IN
# N PRE-
# IGNITION MODE.
# INPUTS - TET PIPTIME
# RIGNTION RN
# VIGNTION VN
# OUTPUTS - PIPTIME AXISD
# RN /ACF/
# VN
# TULLG
# POINTVSM
# ERASABLES - AMEMORY THROUGH SAME
# AMEMORY +217 OCT
# PLUS 6 FOR CPT6/2 (NOT
# YET ASSIGNED)
# SUBROUTINES CALLED - ROOTPSRS ROOTPSRS
# VPATCHER FINDCDUD
# CALCRVG THROTCON
## Page 817
BANK 22
EBANK= E2DPS
# ************************************************************************
# INITIALIZATION OF SECOND DPS GUIDANCE - PREBURN
# ************************************************************************
PREBURN = INIT2DPS
INIT2DPS TC PRETINIT # INITIALIZES INTERPRETER
# CLEAR ORBITAL INTEGRATION VARIABLES FROM REGISTERS IN COMMON WITH 2DPS
TC INTPRET
DLOAD
TET # EXTRAPOLATED TIME FROM ORBITAL INTEGRATN
STCALL PIPTIME # TIME REGISTER OF PIPASR
VPATCHER # TRANSFERS RIGNTION, VIGNTION TO RN, VN,
EXIT # AND DUPLICATES FUNCTIONS OF NORMLIZE
TC PHASCHNG # PREVENTS REREADING ORBITAL INTEGRATION
+402 OCT 04022 # VARIABLES AFTER WRITING OVER THEM
# COMMON REGISTERS ARE CLEARED
TC INTPRET
DLOAD
IGNALGL
STOVL AVGEXIT # SET UP RETURN ADDRESS IN AVGEXIT
ZEROPOS
STORE GDOTM1 # DERIVATIVE OF G FOR USE BY IGNITN1
STODL UNAFC/2
ZEROPOS
STORE TTF/4TMP # ZERO AS IF COMING FROM PREVIOUS PHASE
EXIT
CA ZEROPOS
TS FLPASS0 # SHOWS THIS IS INITIAL PASS THIS PHASE
TC XTRTPIP # SETS TPIP EXTRAPOLATED
CA POSMAX
TS /AFC/ # FORCES INITIALIZATION OF COUNTFC
TS /AFC/ +1 # ONLY REASON: TO ASSURE GOOD PARITY
TS COUNTFCT # ONLY REASON: TO ASSURE GOOD PARITY
TC AVGEXIT # RETURNS TO APPROPRIATE LOCATION IN 2DPS
## Page 818
# ************************************************************************
# SECOND DPS FLITE SEQUENCE TABLE
# ************************************************************************
# INDIRECT ADDRESSES
BURN = QUAD0X
BRTTFNU = 1
PARL = 2
TBRL = 3
TTF/4CR = 4
BRXEND = 5
IGNALG TCF TTFINCR
TCF ADTTFNU # AS IF COMING FROM PREVIOUS PHASE
OCT 00000
ADRES TBRIGAL
DEC -1.5 E2 B-15 # -1.5 SECONDS, TTF UNITS, COMPARES TTF/4
TCF EXIGEND
QUAD0X TCF TTFINCR
TCF RETTTFNU # AS IF CONTINUING PREBURN PHASE
OCT 00000
ADRES TBRQUAD
DEC -045 E2 B-15 # -045 SECONDS, TTF UNITS, COMPARES TTF/4
TCF EXQDLIN
QUAD0F TCF TTFINCR
TCF ADTTFNU
OCT 00027
ADRES TBRQUAD
DEC -3.0 E2 B-15 # -3.0 SECONDS, TTF UNITS, COMPARES TTF/4
TCF EXQDLIN
LING0F TCF LSETEVN
TCF RETTTFNU
OCT 00027
ADRES TBRLING
DEC -.50 E2 B-15 # -.50 SECONDS, TTF UNITS, COMPARES TTF/4
TCF EXQDLIN
LING1F TCF LSETODD
TCF ADTTFNU
OCT 00056
ADRES TBRLING
DEC -.50 E2 B-15 # -.50 SECONDS, TTF UNITS, COMPARES TTF/4
TCF EXQDLIN
QUAD2F TCF TTFINCR
TCF ADTTFNU
## Page 819
OCT 00065
ADRES TBRQUAD
DEC -3.0 E2 B-15 # -3.0 SECONDS, TTF UNITS, COMPARES TTF/4
TCF EXQDLIN
LING2F TCF LSETEVN
TCF RETTTFNU
OCT 00065
ADRES TBRLING
DEC -.50 E2 B-15 # -.50 SECONDS, TTF UNITS, COMPARES TTF/4
TCF EXQDLIN
LING3F TCF LSETODD
TCF ADTTFNU
OCT 00114
ADRES TBRLING
## The following line is supposed to read "DEC -.25 E2 B-15", which is supposed to
## assemble to the octal 77763 ... but actually assembles to 77762. For the present,
## it is being hard-coded as "OCT 77763" as a workaround.
OCT 77763 # -.25 SECONDS, TTF UNITS, COMPARES TTF/4
TCF EXFINAL
# ************************************************************************
# SECOND DPS ROAD MAPS (BRANCH TABLES)
# ************************************************************************
# INDIRECT ADDRESSES
BRIGN1 = 0
BRLING = 1
BRIGN2 = 2
BRXMID = 3
TBRIGAL TCF IGNITN1
TCF TTF/4CL
TCF IGNITN2
TCF EXIGMID
TBRQUAD TCF RETIGN1
TCF TTF/4CL
TCF RETIGN2
TCF EXQDLIN
TBRLING TCF RETIGN1
TCF LINGUID
TCF RETIGN2
TCF EXQDLIN
## Page 820
# ************************************************************************
# INITIALIZATION FOR EACH PASS
# ************************************************************************
# NTLZPASS SETS INDICES, FILLS TPIPOLD, TPIP, R, V EVERY PASS; BRANCHES TO IGNITN1, ADTTFNU WHEN APPROPRIATE.
NTLZPASS EXTEND
QXCH RETNTLZ
TC PRETINIT # INITIALIZES INTERPRETER
# SET INDICES
EXTEND
INDEX AVGEXIT
DCA PARL # LOADS ADRESES OF PARMTR AND BRANCH TABLS
DXCH NDX2DPS
EXTEND
DCS NDX2DPS
INDEX FIXLOC
DXCH X1 # LOADS BOTH INTRP NDX REGS, NEEDED OR NOT
# FILL TPIPOLD AND TPIP
EXTEND
DCA TPIP
DXCH TPIPOLD
TC PHASCHNG # PROTECT TPIPOLD AND
+402 OCT 04022 # PREVENT RETURNING TO PREVIOUS PROGRAM
EXTEND
DCA PIPTIME
DXCH TPIP
# FILL R AND V
TC INTPRET
VLOAD
RN
STOVL R # RN TO R WITHOUT RESCALING
VN
VSR2
STORE V # VN TO V WITH SCALING ADJUSTMENT
EXIT
# IGNITN1 AND ADTTFNU BRANCH DECISIONS
INDEX NDXBR
TCF BRIGN1 # TO IGNITN1 WHEN APPROPRIATE
RETIGN1 TC PHASCHNG # RETURN HERE WHETHER OR NOT DO IGNITN1.
+402 OCT 04022 # PROTECT TTF/4TMP AS USED BY IGNITN1 FROM
## Page 821
# WIPEOUT BY ADTTFNU AND TTFINCR. ALSO
# PROTECT RTEMP, VTEMP FROM RS, VS (SHARE)
CCS FLPASS0
TCF TTFINCR +1 # ON OTHER THAN FIRST PASS IN ANY PHASE.
INDEX AVGEXIT
TCF BRTTFNU # TO ADTTFNU WHEN APPROPRIATE
# ADD TTF/4NU TO TTF/4 FROM LAST PASS
ADTTFNU EXTEND
DCA TTF/4
DXCH TTF/4TMP
INDEX NDX2DPS
CA TTF/4NU
ADS TTF/4TMP
TC PHASCHNG # PROTECT TTF/4
+402 OCT 04022
EXTEND
DCA TTF/4TMP
DXCH TTF/4 # RENEWED TTF/4
TC PHASCHNG # PROTECT TTF/4TMP FROM WIPEOUT BY TTFINCR
+402 OCT 04022
RETTTFNU TC RETNTLZ
# ************************************************************************
# INCREMENT TTF/4
# ************************************************************************
TTFINCR TC NTLZPASS
+1 EXTEND
DCS TPIPOLD
DXCH MPAC
EXTEND
DCA TPIP
DAS MPAC
CA TSCALE
TC DMPNSUB # (TPIP-TPIPOLD)/4 TO MPAC, TTF UNITS
EXTEND
DCA TTF/4
DAS MPAC # YIELDS INCREMENTED TTF/4 IN MPAC
DXCH MPAC
DXCH TTF/4TMP
TC PHASCHNG # PROTECT TTF/4
+402 OCT 04022
EXTEND
## Page 822
DCA TTF/4TMP
DXCH TTF/4 # INCREMENTED TTF/4
# ************************************************************************
# SET UP STATE IN LOCAL, PLANE, SPHERICAL COORDINATES
# ************************************************************************
STUP2DPS TC INTPRET
VLOAD UNIT
R
STOVL CLT/2 # DEFINITION OF MATRIX CLT/2
CPT6/2
VXV UNIT
CLT/2
STOVL CLT/2 +6
CLT/2
VXV VSL1
CLT/2 +6
STOVL CLT/2 +14
V
MXV VSL1
CLT/2 # - * -
STOVL VL # VL = 2 CLT/2 V
R
DOT SL1
CPT6/2 # - -
STOVL RP2 # RP2 = 2 R.CPT6/2
R
VXV DOT
V
CPT6/2
SL1 # - - -
STOVL MAP2 # MAP2 = 2 R*V.CPT6/2
R
ABVAL # -
STODL RLENGTH # RLENGTH = ABVAL(R)
RP2
DSQ PDDL
RLENGTH
DSQ DSU
SQRT # 2 2
STODL RC # RC = SQRT(RLENGTH -RP2 )
RLENGTH # -
STODL RS # DEFINITION OF RS, FIRST COMPONENT
RC
DDV
RLENGTH
STODL CRS2 # COSINE (RS2) = RC/RLENGTH
## Page 823
RP2
DDV
RLENGTH
STODL SRS2 # SINE (RS2) = RP2/RLENGTH
RP2
DDV
RC
STODL TRS2 # TANGENT (RS2) = RP2/RC
SRS2
SR1 ARCSIN
DMP SL3
PI/4 # -
STODL RS +4 # DEFINITION OF RS, THIRD COMPONENT
VL +4
DDV PDDL # THIS PUSH DOWN IS FOR 3RD COMP OF VS.
RLENGTH
VL +2
DDV PDDL # THIS PUSH DOWN IS FOR 2ND COMP OF VS.
RC
VL
VDEF # DEFINITION OF SPHERICAL VELOCITY VECTOR
STODL VS
VS +2
DSQ
DMP DMP
SRS2
CRS2
PDDL DMP
VS +4
VS
DDV SL1
RLENGTH
DAD DCOMP
PDDL DMP # THIS PUSH DOWN IS FOR 3RD COMP OF ASPRT.
VS +2
VS
DDV
RLENGTH
PDDL DMP
TRS2
VS +4
DMP
VS +2
DSU SL1
PDDL DSQ # THIS PUSH DOWN IS FOR 2ND COMP OF ASPRT.
RLENGTH
BDDV
MUEARTH
PDDL DSQ
VS +4
## Page 824
DMP # -
RLENGTH # THIS MONSTER ASPRT REPRESENTS
PDDL DSQ # INCIDENTAL ACCELERATIONS; DUE
CRS2 # TO GRAVITY, CORIOLIS FORCES,
PDDL DSQ # AND SO FORTH.
VS +2
DMP DMP
RLENGTH
DAD DSU
VDEF # DEFINITION OF ASPRT
STORE ASPRT
EXIT
CA ZERO # SECOND COMPONENTS
TS RS +2 # OF RS AND VS ARE
TS RS +3 # ZEROED HERE TO PREVENT
TS VS +2 # OVERFLOW TROUBLE IN
TS VS +3 # THE ACS EQUATION.
TC PHASCHNG # TIME ONLY?
+402 OCT 04022
INDEX NDXBR
TCF BRLING # POSSIBLE BRANCH TO LINEAR GUIDANCE
## Page 825
# ************************************************************************
# TTF/4 COMPUTATION
# ************************************************************************
TTF/4CL EXTEND
INDEX NDX2DPS
DCA JDS2
DXCH TABLTTF +6 # A(3) = JDS2 TO TABLTTF
EXTEND
INDEX NDX2DPS
DCA ADS +4
DDOUBL
DXCH MPAC
CA SP3/4
TC SHORTMP # LEAVING A(2) IN MPAC
DXCH MPAC
DXCH TABLTTF +4 # A(2) = (6 ADS2)/4 TO TABLTTF
CA BIT8
TS TABLTTF +10 # FRACTIONAL PRECISION FOR TTF TO TABLE
EXTEND
DCA VS +4
DXCH MPAC
CA SP3/8
TC SHORTMP # YIELDS 6/16 VS2 IN MPAC
EXTEND
INDEX NDX2DPS
DCA VDS +4
DDOUBL
DXCH MPAC
DXCH TABLTTF +2 # STORE 6/16 VS2 IN TABLTTF
CA SP9/16
TC SHORTMP # YIELDS 18/16 VDS2 IN MPAC
EXTEND
DCS RS +4
DXCH MPAC # -RS2 TO MPAC, FETCHING 18/16 VDS2
DAS TABLTTF +2 # A(1) = (6 VS2+18 VDS2)/16
EXTEND
INDEX NDX2DPS
DCA RDS +4
DAS MPAC # YIELDS -RS2+RDS2 IN MPAC
CA SP3/8
TC SHORTMP
EXTEND
DCA MPAC
DXCH TABLTTF # A(0) =-24(RS2-RDS2)/64
INHINT # SET INHIBITED LOOP TO STORE FOR DWNLINK
CAF ELEVEN # INITIALIZE INDEX TO DEC 11
RVSTOR TS RUPTREG1
## Page 826
INDEX RUPTREG1
CA RN1
INDEX RUPTREG1
TS RN # STORE UPDATED RN, VN
CCS RUPTREG1
TCF RVSTOR
EXTEND
DCA PIPTIMET
DXCH PIPTIME # UPDATED PIPTIME
EXTEND
DCA PIPTIME
DXCH STATIME # STATE TIME FOR DWNLINK
RELINT
TC PHASCHNG # TIME ONLY?
+402 OCT 04022
# ************************************************************************
# QUADRATIC GUIDANCE - SPHERICAL ACCELERATION AS QUADRATIC TIME FUNCTION
# ************************************************************************
# -
# ACS EQUATION IS PROGRAMMED LIKE THIS:
# - -
# - - 1/2(RS-RDS)
# (VS+VDS) - -----------
# - TTF/4 -
# ACS = ---------------------- + ADS
# 2/3(TTF/4)
TC INTPRET
DLOAD DMP
TTF/4
2DPS2/3
PDVL VSU*
RS
RDS,1
VSR1 V/SC
TTF/4
PDVL VAD*
VS
VDS,1
VSU V/SC
VAD*
ADS,1
STORE ACS # BEHOLD, UNWORTHY MORTAL
VSU
ASPRT # - - -
STODL AFCS # AFCS = ACS - ASPRT
## Page 827
RC
DSQ DMP
TTF/4
PDDL DSU
MAP2
MADP2
SR2
DDV STADR # 2
STODL AFCS +2 # AFCS = 1/4(MAP -MADP )/RC (TTF/4)
AFCS +4 # 1 2 2
# ************************************************************************
# THRUST ACCEL POINTING AND MAGNITUDE COMMANDS - DUE TO QUAD OR LINR GUID
# ************************************************************************
AFCCALC DMP PDDL # COMES HERE FROM LINGUID.
RLENGTH
AFCS +2
DMP PDDL
RC
AFCS
VDEF VXM
CLT/2
VSL1 # - *
STORE AFC # AFC = 2(AFCS , RC AFCS ,RLENGTH AFCS )CLT/2
UNIT # 0 1 2
STODL UNAFC/2
36D # MAGNITUDE OF AFC, /AFC/
STORE /AFC/ # FOR IGNITION ALGORITHM
SR1R # CONVERTS /AFC/ TO THROTCON UNITS, /ACF/
STORE /ACF/ # FOR THROTTLE CONTROL SUBR THROTCON
EXIT
INDEX NDXBR
TCF BRIGN2
-3 TS OVFIND # RETURN FROM TTF/4 OVERFLOW
-2 CA FIVE # RETURN RESETTING COUNTFC
-1 TS COUNTFCT # RETURN DECREMENTING COUNTFC
RETIGN2 TC PHASCHNG # RETURN (NORMAL) FROM IGNITN2
+402 OCT 04022 # PREVENT GOING FAR BACK IN 2DPS AFTR EXIT
# ************************************************************************
# PREPARE TO EXIT
# ************************************************************************
INCR FLPASS0 # INCR FIRST PASS FLAG. REPEATS ARE OK.
## Page 828
INDEX AVGEXIT
CS TTF/4CR
AD TTF/4
EXTEND
INDEX NDXBR
BZMF BRXMID # CONTINUE PRESENT PHASE
CA AVGEXIT # PREPARE FOR NEW PHASE
TS AVGXTEMP # TEMPORARY PROTECTION FOR AVGEXIT
TC PHASCHNG # PROTECT AVGEXIT
+402 OCT 04022
CA AVGXTEMP
AD SIX
TS AVGEXIT
CA ZERO
TS FLPASS0 # RESET FLAG INDICATING PASS ZERO (FIRST)
INDEX AVGXTEMP
TCF BRXEND
## Page 829
# ************************************************************************
# ROUTINES FOR EXITING FROM SECOND DPS GUIDANCE. THESE ARE:
# ************************************************************************
# 1. EXIGMID CALLS CALCRVG AS AN INTERPRETIVE SUBROUTINE UP UNTIL BUT NOT INCLUDING THE LAST PASS DURING
# THE PREBURN PHASE. UPON RETURN EXIGMID RESTARTS 2DPS.
# 2. EXIGEND IS USED ON THE LAST PASS DURING PREBURN. IT SETS UP FOR KALCMANU, FOR THE SUBSEQUENT 2DPS
# BURN, AND EXITS TO THE MISSION CONTROL PROGRAM.
# 3. EXQDLIN IS USED TO TERMINATE EACH PASS UP UNTIL BUT NOT INCLUDING THE LAST PASS ON ALL 2DPS BURN
# PHASES. EXQDLIN OBTAINS ATTITUDE AND THROTTLE CONTROL AND TERMINATES THE JOB.
# 4. EXFINAL IS THE FINAL 2DPS EXIT. IT SETS UP THE ATTITUDE COMMAND FOR RANDOM THROTTLING, OBTAINS
# ATTITUDE AND THROTTLE CONTROL, AND EXITS TO THE MISSION CONTROL PROGRAM.
# EXIGMID SETS UP FOR CALCRVG TO MOVE STATE FORWARD A SPECIFIED TIME, INITIALIZES THE INTERPRETER, CALLS CALCRVG
# AS AN INTERPRETIVE SUBROUTINE, AND UPON RETURN SETS UP FOR IGNALG AND BRANCHES INDIRECTLY THERETO.
EXIGMID TC PRETINIT # INITIALIZES INTERPRETER FOR CALCRVG
# SUCCEEDING CODING MUST NOT UNDO
TC INTPRET
DLOAD DAD
PIGNALG
PIPTIME
STOVL PIPTIMET # UPDATED PIPTIME TEMPORARY STORAGE
ZEROPOS
STCALL DELV # DELV = 0
CALCRVG # STEPS FORWARD IN TIME LEAVING RN1, VN1
EXIT
CA E2DPSL # ASSURE CORRECT EBANK BEFORE
TS EBANK # DOING PHASCHNG
TC PHASCHNG # PROTECT PIPTIME. PREVENT REDOING CALCRVG
+402 OCT 04022
TC INTPRET
DLOAD
PIPTIMET
STOVL PIPTIME # UPDATED PIPTIME
RN1
STOVL RN # UPDATED POSITION
VN1
STORE VN # UPDATED VELOCITY
EXIT
TC AVGEXIT # RETURNS TO APPROPRIATE LOCATION IN 2DPS.
## Page 830
# EXIGEND EXTRAPOLATES UNAFC/2 TO TTF/4 = 0, SETS UP FOR MISSION CONTROL PROGRAM, SETS UP FOR THE SUCCEEDING
# BRAKING PHASE, AND EXITS TO THE MISSION CONTROL PROGRAM.
# EXTRAPOLATE UNAFC/2
# UNAFC/2 = UNAFC/2+(UNAFC/2-UNAFC/2O)(TTF)/(TPIPOLD-TPIP)
EXIGEND EXTEND
DCA TPIPOLD
DXCH MPAC
EXTEND
DCS TPIP
DAS MPAC
CA TSCALE
EXTEND
MP BIT3 # MULTIPLIES BY N = 4 LEAVING RESULT IN L
CA L # ASSUMES N(TPIPOLD-TPIP)/4>TTF/4 IN MAGN.
TC DMPNSUB # N(TPIPOLD-TPIP)/4 TO MPAC, TTF UNITS
EXTEND
DCA TTF/4
DXCH MPAC # DIVIDEND TO MPAC
DXCH BUF # DIVISOR TO BUF
TC USPRCADR
CADR DDV/BDDV # (TTF/4)/(N(TPIPOLD-TPIP)/4) TO MPAC
CA ZERO
TS MODE # TO INDICATE DP IN MPAC
TC INTPRET
PDVL VSU
UNAFC/2
UNAFC/20
VSL2 VXSC # VSL2 UNDOES MP BIT3 PRECEDING
UNAFC/2
VAD
UNAFC/2 # YIELDS EXTRAPOLATED UNAFC/2
# SET UP FOR MISSION CONTROL PROGRAM
STODL POINTVSM # STORE FOR KALCMANU
TTF/4
DCOMP DMP
TSCALINV
DAD
PIPTIME
STORE TULLG # TIME AT WHICH ULLAGE IS TO START
# SET UP FOR BRAKING PHASE
EXIT
## Page 831
TC PHASCHNG # PROTECT TTF/4 AND PREVENT REREADING REG-
+402 OCT 04022 # ISTERS REWRITTEN BY MISN CONT PROGRAM
EXTEND
DCA TTF/4TMP
DXCH TTF/4
# RETURN TO MISSION CONTROL PROGRAM
TC PRETINIT # INITIALIZES INTERPRETER
EXTEND
DCA RETPREBL
DTCB
## Page 832
# EXQDLIN STORES THE SEMI-UNIT VECTOR DEFINING THE DIRECTION OF COMMANDED THRUST ACCELERATION (UNAFC/2) IN THE
# APPROPRIATE REGISTERS OF FINDCDUD (AXISD) AND CALLS FINDCDUD AS A SUBROUTINE.
# THEN EXQDLIN TRANSFERS THE COMMANDED THRUST ACCELERATION MAGNITUDE (/AFC/) TO THE APPROPRIATE REGISTERS OF
# THROTCON, (/ACF/), CHANGING SCALING, AND CALLS THROTCON AS A SUBROUTINE.
# FINALLY EXQDLIN TERMINATES THE JOB.
EXQDLIN TC INTPRET
VLOAD
UNAFC/2
STCALL AXISD
FINDCDUD # ATTITUDE CONTROL
EXIT
EXTEND
DCA THROTCOL
DTCB # THROTTLE CONTROL
TC ENDOFJOB # TERMINATES THE JOB PERIODICALLY STARTED
# BY A WAITLIST CALL FROM READACCS
# EXFINAL IS THE FINAL EXIT FROM 2DPS. FIRST EXFINAL PLACES THE SEMI-UNIT NORMAL TO THE ORBITAL PLANE (CPT6/2)
# IN AXISD AND CALLS FINDCDUD AS A SUBROUTINE. THIS CAUSES FURTHER THRUSTING TO BE NORMAL TO THE ORBITAL PLANE.
# THEN EXFINAL TRANSFERS THE COMMANDED THRUST ACCELERATION MAGNITUDE (/AFC/) TO THE APPROPRIATE REGISTERS OF
# THROTCON, (/ACF/), CHANGING SCALING, AND CALLS THROTCON AS A SUBROUTINE.
# FINALLY EXFINAL RETURNS TO THE MISSION CONTROL PROGRAM WHICH EXECUTES THE RANDOM THROTTLING.
EXFINAL TC INTPRET
VLOAD
CPT6/2
STCALL AXISD
FINDCDUD # ATTITUDE CONTROL
EXIT
EXTEND
DCA THROTCOL
DTCB # THROTTLE CONTROL
TC PRETINIT # INITIALIZES INTERPRETER
EXTEND
DCA RETBURNL
DTCB
## Page 833
# ************************************************************************
# SPECIAL PURPOSE SUBROUTINES OF SECOND DPS GUIDANCE
# ************************************************************************
# ************************************************************************
# IGNITION ALGORITHM
# ************************************************************************
# IGNITN1 EXTRAPOLATES THE GIVEN STATE FORWARD THROUGH THE TIME INTERVAL REQUIRED TO ACCOMPLISH ULLAGE AND TO
# LITE AT LOW THRUST AND TRIM THE ENGINE. THE EXTRAPOLATION ENDS AT THE TIME MAXIMUM THRUST WOULD BE COMMANDED
# IF THE LITEUP PROCEDURE WERE INITIATED AT THE CURRENT GIVEN TIME. (THE GIVEN TIME IS NOT TRUE. ALL GIVEN
# CONDITIONS INCLUDE A FREE-FALL EXTRAPOLATION OF THE ACTUAL ORBIT.) THE EXTRAPOLATION PERFORMED BY IGNITN1
# INCLUDES ALL EFFECTS OF ENGINE THRUST DURING THE LITEUP PROCEDURE, AND IT USES THE
# THRUST POINTING DIRECTION WHICH WILL BE COMMANDED AT THE INITIATION OF MAXIMUM THRUST.
# THIS EXTRAPOLATED STATE IS THEN FED TO THE GUIDANCE EQUATIONS, WHICH COMPUTE THE THRUST POINTING
# DIRECTION (UNAFC/2) AND THE THRUST ACCELERATION MAGNITUDE COMMAND (/AFC/).
# IGNITN2 THEN RECEIVES THIS OUTPUT DATA FROM THE GUIDANCE EQUATIONS AND DETERMINES WHETHER THE THRUST
# ACCELERATION MAGNITUDE COMMAND IS MONOTONICALLY INCREASING. WHEN IT IS, IGNITN2 USES THE PRESENT AND PREVIOUS
# VALUES TO COMPUTE ONE QUARTER OF THE PRESENT TIME (TTF/4) RELATIVE TO THE TIME AT WHICH THE THRUST
# ACCELERATION MAGNITUDE COMMAND WILL REACH THE CRITERION VALUE (/AFC/CR) WHICH CORRESPONDS TO MAXIMUM THROTTLE.
# WHEN TTF/4 SO COMPUTED REACHES THE TIME CRITERION FOR TERMINATING THE PREBURN PHASE (TTF/4CR),
# EXIGEND IS PROCESSED, TERMINATING THE PHASE AND RETURNING CONTROL TO THE MISSION CONTROL PROGRAM.
# THE MISSION CONTROL PROGRAM EXECUTES THE COMPUTED IGNITION SEQUENCE. IGNITN2 MUST ALSO, ON EACH PASS,
# REESTABLISH CERTAIN DATA REQUIRED FOR THE SUBSEQUENT PASS.
# IGNITION ALGORITHM PART 1
# ************************************************************************
# DO TEMPORARY STORAGE
IGNITN1 TC INTPRET
DLOAD
/AFC/
STOVL /AFC/OLD # OLD VALUE OF /AFC/ FOR USE BY IGNITN2
UNAFC/2
STOVL UNAFC/20 # OLD VALUE OF UNAFC/2
# EXTRAPOLATE STATE
R
STOVL RDUM
V
STOVL VDUM
GDOTM1
STODL JDUM
PFCULLG # ULLAGE PERIOD
STODL PDUM # DUMMY PERIOD
AFULLG # LEAVE AFULLG IN MPAC
## Page 834
CALL # EXTRAPOLATES DUMMY STATE AND
XTRIGN1 # LEAVES INITIAL GRAVITY IN GDUM
VLOAD
GDUM
STODL GDUMPRES # SAVE INITL GRAVITY FOR COMPUTING GDOTM1
PFCLITE # LITEUP PERIOD
STODL PDUM
AFLITE # LEAVE AFLITE IN MPAC
CALL
XTRIGN1 # EXTRAPOLATE
DLOAD
PFCTRIM # TRIM PERIOD
STODL PDUM
AFTRIM # LEAVE AFTRIM IN MPAC
CALL
XTRIGN1 # YIELDS FINAL EXTRAPOLATED STATE
VLOAD
RDUM
STOVL RTEMP # RESTART PROTECTION FOR EXTRAPOLATED R
VDUM
STCALL VTEMP # RESTART PROTECTION FOR EXTRAPOLATED V
# COMPUTE DERIVATIVE OF GRAVITY
GDUMCL # YIELDS FINAL GRAVITY IN MPAC AND GDUM
VSU V/SC
GDUMPRES
PPHM1 # COMPLETES COMPUTATION OF DERIV OF G
STORE GDOTM1 # FOR USE NEXT PASS. PROTECTION NOT RQD.
EXIT
# GENERATION OF EXTRAPOLATED DATA COMPLETE. PROTECT AND TRANSFER TO STORAGE.
TC PHASCHNG # PROTECT R, V
+402 OCT 04022
TC INTPRET
DLOAD
TTF/4TMP
STOVL TTF/4 # RESTORES TTF/4 TO LAST VALUE BY GUIDANCE
RTEMP
STOVL R # EXTRAPOLATED R
VTEMP
STORE V # EXTRAPOLATED V
EXIT
CA COUNTFCT
TS COUNTFC # FOR IGNITN2
## Page 835
TC XTRTPIP # YIELDS TPIP EXTRAPOLATED
TCF RETIGN1
# IGNITION ALGORITHM PART 2
# ************************************************************************
IGNITN2 EXTEND
DCA TTF/4
DXCH TTF/4TMP # SAVE TTF/4 FOR NEXT PASS
TC PHASCHNG # PROTECT TTF/4
+402 OCT 04022
CS POSMAX
TS TTF/4 # PREVENT PREMATURE TERMINATION OF PREBURN
# TEST WHETHER /AFC/ > /AFC/OLD, IF SO TEST WHETHER COUNTFC = 0.
EXTEND
DCA /AFC/
DXCH MPAC
EXTEND
DCS /AFC/OLD
DAS MPAC # /AFC/-/AFC/OLD IN MPAC
CCS MPAC # TEST HI ORDER
TCF TCOUNTFC
TCF TSTLOAFC
TCF RETIGN2 -2 # RESET COUNTFC
TSTLOAFC CA MPAC +1 # TEST LO ORDER
EXTEND
BZMF RETIGN2 -2 # RESET COUNTFC
TCOUNTFC CCS COUNTFC
TCF RETIGN2 -1 # DECREMENT COUNTFC
# RESET TTF/4 BY EXTRAPOLATING /AFC/
# TTF/4 = (1/4)(TPIPOLD-TPIP)(/AFC/-/AFC/CR)/(/AFC/OLD-/AFC/)
EXTEND
DCA TPIPOLD
DXCH MPAC
EXTEND
DCS TPIP
DAS MPAC
CA TSCALE
TC DMPNSUB # (1/4)(TPIPOLD-TPIP) TO MPAC, TTF UNITS
EXTEND
DCA /AFC/
## Page 836
DXCH MPAC +3
EXTEND
DCS /AFC/CR
DAS MPAC +3
TC DMP
GENADR MPAC +3
EXTEND
DCA /AFC/OLD
DXCH BUF
EXTEND
DCS /AFC/
DAS BUF
TC USPRCADR
CADR DDV/BDDV # YIELDS TTF/4 IN MPAC
CCS OVFIND
TCF RETIGN2 -3 # IF TTF/4 OVFL. RESETS OVFIND, COUNTFC.
DXCH MPAC
DXCH TTF/4
TCF RETIGN2
# ************************************************************************
# SPECIAL PURPOSE STATE EXTRAPOLATION SUBROUTINE FOR IGNITN1
# ************************************************************************
# XTRIGN1 RECEIVES THE EXTRAPOLATION PERIOD IN PDUM; THE INITIAL STATE IN RDUM, VDUM; THE THRUST ACCELERATION
# MAGNITUDE IN MPAC, DIRECTION IN UNAFC/2; AND JERK IN JDUM.
# IT LEAVES GRAVITY IN GDUM, THE TOTAL INITIAL ACCELERATION IN ADUM, AND THE EXTRAPOLATED STATE IN RDUM, VDUM.
# PRESENTLY THE DUM REGISTERS OCCUPY LOCATIONS FIXLOC +6 THRU FIXLOC +45 OCTAL.
XTRIGN1 STQ
RETXIGN1 # SAVE QPRET
SL1 VXSC
UNAFC/2
PUSH CALL # PUSHES AF UNAFC
GDUMCL # YIELDS GRAVITY IN MPAC AND GDUM
VAD STADR
STORE ADUM # ADUM = AF UNAFC+G
CALL
XTRDUMST # EXTRAPOLATES RDUM, VDUM
GOTO
RETXIGN1
## Page 837
# ************************************************************************
# LINEAR GUIDANCE - SPHERICAL ACCELERATION AS LINEAR TIME FUNCTION
# ************************************************************************
# SET LINEAR GUIDANCE COEFFICIENTS IN EVEN NUMBERED PHASES
# ************************************************************************
LSETEVN TC NTLZPASS
TC INTPRET
VLOAD*
ADS,1 # - -
STODL ALINS # ALINS = ADS
AFCS +2
DAD
ASPRT +2
STORE ACS +2
STOVL ALINS +2 # ALINS = ACS = AFCS + ASPRT
ALINS # 2 2 2 2
GOTO
LINSET
# SET LINEAR GUIDANCE COEFFICIENTS IN ODD NUMBERED PHASES
# ************************************************************************
LSETODD TC NTLZPASS
TC INTPRET
VLOAD*
ADS,1 # - -
STORE ALINS # ADINS = ADS
# COMMON PARTS OF LSETEVN AND LSETODD
# ************************************************************************
LINSET BVSU
ACS
VSR2 V/SC
TTF/4 # - - -
STORE JLINS # JLINS = 1/4 (ACS - ALINS)/(TTF/4)
EXIT
TCF TTFINCR +1
# LINEAR GUIDANCE EQUATIONS
# ************************************************************************
LINGUID TC INTPRET
VLOAD VXSC
JLINS
TTF/4
VSL2
VAD VSU
## Page 838
ALINS
ASPRT # - - - -
STODL AFCS # AFCS = 4 JLINS/(TTF/4) + ALINS - ASPRT
AFCS +4
GOTO
AFCCALC
# ************************************************************************
# SUBROUTINE TO SET TPIP EXTRAPOLATED
# ************************************************************************
XTRTPIP EXTEND
DCA PIPTIME
DXCH TPIP
EXTEND
DCA PPHM1CS
DAS TPIP
TC Q
## Page 839
# ************************************************************************
# GENERAL PURPOSE SUBROUTINES CONTRIBUTED BY SECOND DPS GUIDANCE
# ************************************************************************
# ************************************************************************
# DOUBLE PRECISION ROOT FINDER SUBROUTINE
# ************************************************************************
# N N-1
# ROOTPSRS FINDS ONE ROOT OF THE POWER SERIES A X + A X + ... + A X + A
# N N-1 1 0
# USING NEWTON'S METHOD STARTING WITH AN INITIAL GUESS FOR THE ROOT. THE ENTERING DATA MUST BE AS FOLLOWS:
# A SP LOC-3 ADRES FOR REFERENCING PWR COF TABL
# L SP N-1 N IS THE DEGREE OF THE POWER SERIES
# MPAC DP X INITIAL GUESS FOR ROOT
# LOC-2N DP A(0)
# ...
# LOC DP A(N)
# LOC+2 SP PRECROOT PREC RQD OF ROOT (AS FRACT OF 1ST GUESS)
# THE DP RESULT IS LEFT IN MPAC UPON EXIT, AND A SP COUNT OF THE ITERATIONS TO CONVERGENCE IS LEFT IN MPAC+2.
# RETURN IS TO LOC(TC POWRSERS)+1.
# PRECAUTION: ROOTPSRS MAKES NO CHECKS FOR OVERFLOW OR FOR IMPROPER USAGE. IMPROPER USAGE COULD
# PRECLUDE CONVERGENCE OR REQUIRE EXCESSIVE ITERATIONS. AS A SPECIFIC EXAMPLE, ROOTPSRS FORMS A DERIVATIVE
# COEFFICIENT TABLE BY MULTIPLYING EACH A(I) BY I, WHERE I RANGES FROM 1 TO N. IF AN ELEMENT OF THE DERIVATIVE
# COEFFICIENT TABLE = 1 OR > 1 IN MAGNITUDE, ONLY THE EXCESS IS RETAINED. ROOTPSRS MAY CONVERGE ON THE CORRECT
# ROOT NONETHELESS, BUT IT MAY TAKE AN EXCESSIVE NUMBER OF ITERATIONS. THEREFORE THE USER SHOULD RECOGNIZE:
# 1. USER'S RESPONSIBILITY TO ASSURE THAT I X A(I) < 1 IN MAGNITUDE FOR ALL I.
# 2. USER'S RESPONSIBILITY TO ASSURE OVERFLOW WILL NOT OCCUR IN EVALUATING EITHER THE RESIDUAL OR THE DERIVATIVE
# POWER SERIES. THIS OVERFLOW WOULD BE PRODUCED BY SUBROUTINE POWRSERS, CALLED BY ROOTPSRS, AND MIGHT NOT
# PRECLUDE EVENTUAL CONVERGENCE.
# 3. AT PRESENT, ERASABLE LOCATIONS ARE RESERVED ONLY FOR N UP TO 5. AN N IN EXCESS OF 5 WILL PRODUCE CHAOS.
# ALL ERASABLES USED BY ROOTPSRS ARE UNSWITCHED LOCATED IN THE REGION FROM MPAC-33 OCT TO MPAC+7.
# 4. THE ITERATION COUNT RETURNED IN MPAC+2 MAY BE USED TO DETECT ABNORMAL PERFORMANCE.
# STORE ENTERING DATA, INITLIZE ERASABLES
ROOTPSRS EXTEND
QXCH RETROOT # RETURN ADRES
TS PWRPTR # PWR TABL POINTER
DXCH MPAC +3 # PWR TABL ADRES, N-1
CA DERTABLL
## Page 840
TS DERPTR # DER TABL POINTER
TS MPAC +5 # DER TABL ADRES
CCS MPAC +4 # NO POWER SERIES OF DEGREE 1 OR LESS
TS MPAC +6 # N-2
CA ZERO # MODE USED AS ITERATION COUNTER. MODE
TS MODE # MUST BE POS SO ABS WON'T COMP MPAC+3 ETC
# COMPUTE CRITERION TO STOP ITERATING
EXTEND
DCA MPAC # FETCH ROOT GUESS, KEEPING IT IN MPAC
DXCH ROOTPS # AND IN ROOTPS
INDEX MPAC +3 # PWR TABL ADRES
CA 5 # PRECROOT TO A
TC SHORTMP # YIELDS DP PRODUCT IN MPAC
TC USPRCADR
CADR ABS # YIELDS ABVAL OF CRITERION ON DX IN MPAC
DXCH MPAC
DXCH DXCRIT # CRITERION
# SET UP DER COF TABL
EXTEND
INDEX PWRPTR
DCA 3
DXCH MPAC # A(N) TO MPAC
CA MPAC +4 # N-1 TO A
DERCLOOP TS PWRCNT # LOOP COUNTER
AD ONE
TC DMPNSUB # YIELDS DERCOF = I X A(I) IN MPAC
EXTEND
INDEX PWRPTR
DCA 1
DXCH MPAC # A(I-1) TO MPAC, FETCHING DERCOF
INDEX DERPTR
DXCH 3 # DERCOF TO DER TABL
CS TWO
ADS PWRPTR # DECREMENT PWR POINTER
CS TWO
ADS DERPTR # DECREMENT DER POINTER
CCS PWRCNT
TCF DERCLOOP
# CONVERGE ON ROOT
ROOTLOOP EXTEND
DCA ROOTPS # FETCH CURRENT ROOT
DXCH MPAC # LEAVE IN MPAC
## Page 841
EXTEND
DCA MPAC +5 # LOAD A, L WITH DER TABL ADRES, N-2
TC POWRSERS # YIELDS DERIVATIVE IN MPAC
EXTEND
DCA ROOTPS
DXCH MPAC # CURRENT ROOT TO MPAC, FETCHING DERIVTIVE
DXCH BUF # LEAVE DERIVATIVE IN BUF AS DIVISOR
EXTEND
DCA MPAC +3 # LOAD A, L WITH PWR TABL ADRES, N-1
TC POWRSERS # YIELDS RESIDUAL IN MPAC
TC USPRCADR
CADR DDV/BDDV # YIELDS -DX IN MPAC
EXTEND
DCS MPAC # FETCH DX, LEAVING -DX IN MPAC
DAS ROOTPS # CORRECTED ROOT NOW IN ROOTPS
TC USPRCADR
CADR ABS # YIELDS ABS(DX) IN MPAC
EXTEND
DCS DXCRIT
DAS MPAC # ABS(DX)-ABS(DXCRIT) IN MPAC
INCR MODE # INCREMENT ITERATION COUNTER
CCS MPAC # TEST HI ORDER DX
TCF ROOTLOOP
TCF TESTLODX
TCF ROOTSTOR
TESTLODX CCS MPAC +1 # TEST LO ORDER DX
TCF ROOTLOOP
TCF ROOTSTOR
TCF ROOTSTOR
ROOTSTOR DXCH ROOTPS
DXCH MPAC # STORE DP ROOT IN MPAC, MPAC+1
CA MODE
TS MPAC +2 # STORE SP ITERATION COUNT IN MPAC+2
TC RETROOT
DERTABLL ADRES DERCOFN -3
## Page 842
# ************************************************************************
# GENERAL PURPOSE SUBROUTINE FOR EXTRAPOLATING DUMMY STATE RDUM, VDUM
# ************************************************************************
# XTRDUMST REQUIRES THE EXTRAPOLATION PERIOD, INITIAL POSITION, INITIAL VELOCITY, INITIAL ACCELERATION, JERK
# TO ARRIVE IN PDUM, RDUM, VDUM, ADUM, JDUM.
# IT LEAVES THE EXTRAPOLATED STATE IN RDUM, VDUM.
# PRESENTLY THE DUM REGISTERS ARE LOCATIONS FIXLOC +6 THRU FIXLOC +31 OCTAL, AND FIXLOC +40 OCTAL THRU
# FIXLOC +45 OCTAL.
# 2 3
# THE EQNS ARE RDUM = RDUM+VDUM PDUM+ADUM PDUM /2+JDUM PDUM /6,
# 2
# VDUM = VDUM+ADUM PDUM+JDUM PDUM /2.
# THEY ARE PROGRAMMED AS RDUM = ((JDUM PDUM/3+ADUM)PDUM/2+VDUM)PDUM+RDUM
# VDUM = (JDUM PDUM/2+ADUM)PDUM+VDUM
XTRDUMST DLOAD
PDUM
DMP VXSC
1/3DP
JDUM
VAD VXSC
ADUM
PDUM
VSR1 VAD
VDUM
VXSC VAD
PDUM
RDUM
STODL RDUM # EXTRAPOLATED RDUM. NO RESTART PROTECTION
PDUM
SR1R VXSC
JDUM
VAD VXSC
ADUM
PDUM
VAD
VDUM
STORE VDUM # EXTRAPOLATED VDUM. NO RESTART PROTECTION
RVQ
## Page 843
# ************************************************************************
# DUMMY GRAVITY SUBROUTINE
# ************************************************************************
# GDUMCL COMPUTES GRAVITY GIVEN POSITION IN RDUM, LEAVING RESULT IN MPAC AND GDUM.
# 2
# GDUM =-MUEARTH UNIT(RDUM)/((ABVAL(RDUM)) )
GDUMCL VLOAD VCOMP
RDUM
UNIT VXSC
MUEARTH
V/SC VSL1 # SHIFT COMPENSATES FOR SEMI-UNIT
42
STORE GDUM
RVQ
# ************************************************************************
# INTERPRETER INITIALIZATION SUBROUTINE
# ************************************************************************
PRETINIT CA FIXLOC
TS PUSHLOC
CA ZERO
TS OVFIND
TC Q
## Page 844
# ************************************************************************
# SECOND DPS TARGET PARAMETERS
# ************************************************************************
# PARAMETER TABLE INDIRECT ADDRESSES
TTF/4NU = TTF/4N0X
ADS = A0XS
RDS = R0XS
VDS = V0XS
JDS2 = J0XS2
MADP2 = MA0XP2
#
# A CONSISTENT SET OF UNITS IS USED THRUOUT THE SECOND DPS GUIDANCE. THESE UNITS ARE:
# TIME 2( 15)CS; LENGTH 2( 24)M; ANGLE 2( 0)RAD.
# IGNITION ALGORITHM - PREBURN PARAMETERS
# ************************************************************************
PPHM1 2DEC* +3.350000000 E+3 B-15*
PPHM1CS 2DEC* +3.350000000 E+3 B-28*
/AFC/CR 2DEC* +2.965861098 E-4 B+6*
PFCULLG 2DEC* +7.500000000 E+2 B-15*
AFULLG 2DEC* +6.074952094 E-6 B+6*
PFCLITE 2DEC* +3.000000000 E+2 B-15*
AFLITE 2DEC* +3.198162867 E-5 B+6*
PFCTRIM 2DEC* +2.300000000 E+3 B-15*
AFTRIM 2DEC* +3.202931538 E-5 B+6*
## Page 845
# PARAMETER TABLE FOR BURN PHASES
# ************************************************************************
TTF/4N0X DEC* -1.125000000 E+4 B-15*
A0XS 2DEC* -8.572092116 E-5 B+6*
2DEC 0
2DEC* +7.269884947 E-11 B+30*
R0XS 2DEC* +6.713370537 E+6 B-24*
2DEC 0
2DEC* +1.056080555 E-2 B-0*
V0XS 2DEC* -1.071382748 E+0 B-9*
2DEC 0
2DEC* -9.160545259 E-7 B+15*
J0XS2 2DEC* +1.194804087 E-15 B+45*
MA0XP2 2DEC* +5.156859816 E+8 B-33*
## Page 846
TTF/4N0F DEC* -2.500000000 E+3 B-15*
A0FS 2DEC* -5.038447857 E-5 B+6*
2DEC 0
2DEC* +4.273045103 E-11 B+30*
R0FS 2DEC* +6.700335070 E+6 B-24*
2DEC 0
2DEC* +3.369214099 E-3 B-0*
V0FS 2DEC* -1.545589897 E+0 B-9*
2DEC 0
2DEC* -5.138853270 E-7 B+15*
J0FS2 2DEC* +5.027062289 E-16 B+45*
MA0FP2 2DEC* +5.156859816 E+8 B-33*
TTF/4NU1 DEC* -1.000000000 E+2 B-15*
A1FS 2DEC* +5.044035031 E-5 B+6*
2DEC 0
2DEC* +4.277783493 E-11 B+30*
## Page 847
## Workaround: the following line has been changed to OCT because yaYUL produces
## slightly different numerical results. The original was as follows:
## TTF/4NU2 DEC* -3.375000000 E+3 B-15*
TTF/4NU2 OCT 74550
A2FS 2DEC* +1.331951587 E-4 B+6*
2DEC 0
2DEC* +1.991810043 E-11 B+30*
R2FS 2DEC* +6.687217073 E+6 B-24*
2DEC 0
2DEC* +1.144811884 E-5 B-0*
V2FS 2DEC* -1.198407174 E-1 B-9*
2DEC 0
2DEC* -2.215170344 E-8 B+15*
J2FS2 2DEC* -3.386627333 E-15 B+45*
MA2FP2 2DEC* +5.156859816 E+8 B-33*
TTF/4NU3 DEC* -2.500000000 E+2 B-15*
A3FS 2DEC* +1.536879692 E-13 B+6*
2DEC 0
2DEC* +2.438530673 E-11 B+30*
## Page 848
# ************************************************************************
# SECOND DPS CONSTANTS
# ************************************************************************
# ADDRESS CONSTANTS
E2DPSL ECADR E2DPS # FOR ACCESSING EBANK OF 2DPS
EBANK= E2DPS
IGNALGL 2BCADR IGNALG
# THE NEXT TWO CONSTANTS MUST BE KEPT
# IN ORDER AND ADJACENT
TABLTTFL ADRES TABLTTF +3 # ADRES TO REF TTF TABL
DEGTTF-1 OCT 2 # DEGREE-1 OF TTF POWER SERIES
EBANK= EMP11JOB
RETPREBL 2BCADR RETPREB
EBANK= EMP11JOB
RETBURNL 2BCADR RETBURN
EBANK= ETHROT
THROTCOL 2BCADR THROTCON
# ARITHMETIC FRACTIONS AND INTEGERS
TSCALE = BIT12
TSCALINV OCT 00010
ZEROPOS OCT 00000 # LO ORDER PART OF TSCALINV, AND
OCT 00000 # FIRST COMPONENT OF ZERO VECTOR
ZERONEG OCT 77777
OCT 77777
OCT 00000 # LAST COMPONENT OF ZERO VECTOR, AND
PIGNALG OCT 00000 # HI ORDER PART OF PIGNALG, TPIP UNITS
DEC +2 E+2B-14 # LO ORDER PART OF PIGNALG, TPIP UNITS
1/3DP 2DEC .3333333333
## The following line is "SP3/8 OCT .3 B14" in the original program listing, but the yaYUL
## assembler does not syntactically support this syntax for OCT, so it has been replaced
## by a numerical equivalent that the assembler does support.
SP3/8 DEC .375 B14
## The following line is "SP9/16 OCT .44 B14" in the original program listing, but the yaYUL
## assembler does not syntactically support this syntax for OCT, so it has been replaced
## by a numerical equivalent that the assembler does support.
SP9/16 DEC .5625 B14
2/3DP 2DEC .6666666667
2DPS2/3 = 2/3DP
## The following line is "SP3/4 OCT .6 B14" in the original program listing, but the yaYUL
## assembler does not syntactically support this syntax for OCT, so it has been replaced
## by a numerical equivalent that the assembler does support.
SP3/4 DEC .75 B14
PI/4 2DEC +3.14159265 B-2
## Page 849
# ************************************************************************
# VARIOUS TEMPORARY TEST ROUTINES FOR SUBROUTINES CONTRIBUTED BY 2DPS
# ************************************************************************
# TEST ROOTPSRS ON 5TH DEGREE POWER SERIES
RUTTEST EXTEND
DCA RUTINIT
DXCH MPAC
EXTEND
DCA RUTTABLL
TC ROOTPSRS
# TEST POLY ON SIN 30 DEGREES
POLYTEST TC INTPRET
DLOAD SIN
QTSTPOLY
# TEST USEPRET ON V/SC
STOVL RC
A2FS
STORE RS
EXIT
CA OCT1/2L
TS ADDRWD
TC USEPRET
TC V/SC
TC INTPRET
STORE VS
EXIT
END2DPST CA ONE
# TEMP CONSTANTS FOR TESTS
## The following line is "RTUNIT OCT .6 B14" in the original program listing, but the yaYUL
## assembler does not syntactically support this syntax for OCT, so it has been replaced
## by a numerical equivalent that the assembler does support.
RUTINIT DEC .75 B14
OCT 0
OCT 0
OCT 0
## The following line is "OCT +.001 B14" in the original program listing, but the yaYUL
## assembler does not syntactically support this syntax for OCT, so it has been replaced
## by a numerical equivalent that the assembler does support.
DEC 1.953125 E-3 B14
OCT 0
OCT 0
OCT 0
## The following line is "OCT -.024 B14" in the original program listing, but the yaYUL
## assembler does not syntactically support this syntax for OCT, so it has been replaced
## by a numerical equivalent that the assembler does support.
DEC -3.90625 E-2 B14
## Page 850
OCT 0
OCT 0
OCT 0
## The following line is "RUTTABL OCT +.100 B14" in the original program listing, but the yaYUL
## assembler does not syntactically support this syntax for OCT, so it has been replaced
## by a numerical equivalent that the assembler does support.
RUTTABL DEC +.125 B14
OCT 0
RUTPREC OCT 1
RUTTABLL ADRES RUTTABL -3
OCT 4
QTSTPOLY 2DEC .083333333
## The following line is "OCT1/2 OCT .4 B14" in the original program listing, but the yaYUL
## assembler does not syntactically support this syntax for OCT, so it has been replaced
## by a numerical equivalent that the assembler does support.
OCT1/2 DEC .5 B14
OCT 0
OCT1/2L ADRES OCT1/2
