AGS_INITIALIZATION.agc
### FILE="Main.annotation"
## Copyright: Public domain.
## Filename: AGS_INITIALIZATION.agc
## Purpose: A section of Luminary revision 210.
## It is part of the source code for the Lunar Module's (LM)
## Apollo Guidance Computer (AGC) for Apollo 15-17.
## 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. 218-221
## Assembler: yaYUL
## Contact: Ron Burkey <info@sandroid.org>.
## Website: www.ibiblio.org/apollo/index.html
## Mod history: 2016-11-17 JL Created from Luminary131 version.
## 2016-11-22 HG Transcribed
## 2016-12-23 RSB Proofed comment text with octopus/ProoferComments
## and fixed all errors found.
## Page 218
# PROGRAM NAME: AGS INITIALIZATION (R47)
# WRITTEN BY : RHODE/KILROY/FOLLETT
# MOD NO. : 0
# DATE : 23 MARCH 1967
# MOD BY : KILROY
# MOD NO. : 1
# DATE : 28 OCTOBER 1967
# MOD BY : FOLLETT
# FUNCT. DESC.: (1) TO PROVIDE THE AGS ABORT ELECTRONICS ASSEMBLY(AEA) WITH THE LEM AND CSM STATE VECTORS
# (POSITION,VELOCITY,TIME) IN LEM IMU COORDINATES BY MEANS OF THE LGC DIGITAL DOWNLINK.
#
# (2) TO ZERO THE ICDU, LGC AND AEA GIMBAL ANGLE COUNTERS SIMULTANEOUSLY IN ORDER TO ESTABLISH A
# COMMON ZERO REFERENCE FOR THE MEASUREMENT OF GIMBAL(EULER) ANGLES WHICH DEFINE LEM ATTITUDE
# (3) TO ESTABLISH THE GROUND ELAPSED TIME OF AEA CLOCK ZERO.(IF AN AEA CLOCK ZERO IS
# REQUESTED DURING THIS PROGRAM
# LOG SECTION : AGS INITIALIZATION
# CALLING SEQ : PROGRAM IS ENTERED WHEN ASTRONAUT KEYS V47E ON DSKY.
# R47 MAY BE CALLED AT ANY TIME EXCEPT WHEN ANOTHER EXTENDED VERB IS IN PROGRESS
# SUBROUTINES
# CALLED :
#
# NORMAL EXIT : ENDEXT
#
# ALARM/ABORT : ALARM - BAD REFSMMAT - CODE:220
# OPERATOR ERROR IF V47 SELECTED DURING ANOTHER EXTENDED VERB.
#
# ERASABLES
# USED : SAMPTIME (2) TIME OF :ENTER: KEYSTROKE
# AGSK (2) GROUND ELAPSED TIME OF THE AEA CLOCK :ZERO:
# AGSBUFF (140) CONTAINS AGS INITIALIZATION DATA (SEE :OUTPUT: BELOW)
# AGSWORD (1) PREVIOUS DOWNLIST SAVED HERE
EBANK= AGSK
BANK 40
SETLOC R47
BANK
COUNT* $$/R47
AGSINIT CAF REFSMBIT
MASK FLAGWRD3 # CHECK REFSMFLG.
CCS A
TC REDSPTEM # REFSMMAT IS OK
## Page 219
TC ALARM # REFSMMAT IS BAD
OCT 220
TC ENDEXT
NEWAGS EXTEND
DCA SAMPTIME # TIME OF THE :ENTER: KEYSTROKE
DXCH AGSK # BECOMES NEW AEA CLOCK :ZERO:
REDSPTEM EXTEND
DCA AGSK
DXCH DSPTEMX
AGSDISPK CAF V06N16
TC BANKCALL # R1 = 00XXX. HRS., R2 = 000XX MIN.,
CADR GOMARKF # R3 = 0XX.XX SEC.
TC ENDEXT # TERMINATE RETURN
TC AGSVCALC # PROCEED RETURN
CS BIT6 # IS ENTER VIA A V32
AD MPAC
EXTEND
BZF NEWAGS # YES, USE KEYSTROKE TIME FOR NEW AGSK
EXTEND # NO, NEW AGSK LOADED VIA V25
DCA DSPTEMX # LOADED INTO DSPTEMX BY KEYING
TC REDSPTEM -1 # V25E FOLLOWED BY HRS.,MINS.,SECS.
# DISPLAY THE NEW K
AGSVCALC TC INTPRET
SET EXIT
XDSPFLAG
CAF V06N16
TC BANKCALL
CADR EXDSPRET
TC INTPRET # EXTRAPOLATE LEM AND CSM STATE VECTORS
RTB # TO THE PRESENT TIME
LOADTIME # LOAD MPAC WITH TIME2,TIME1
STCALL TDEC1 # CALCULATE LEM STATE VECTOR
LEMPREC
CALL # CALL ROUTINE TO CONVERT TO SM COORDS AND
SCALEVEC # PROVIDE PROPER SCALING
STODL AGSBUFF # (LEMPREC AND CSMPREC LEAVE TDEC1 IN TAT)
TAT # TAT = TIME TO WHICH RATT1 AND VATT1 ARE
STCALL TDEC1 # COMPUTED(CSEC SINCE CLOCK START B-28).
CSMPREC # CALCULATE CSM STATE VECTOR FOR SAME TIME
CALL
SCALEVEC
STODL AGSBUFF +6
TAT
DSU DDV # CALCULATE AND STORE THE TIME
## Page 220
AGSK
TSCALE
STORE AGSBUFF +12D
EXIT
CAF LAGSLIST
TS DNLSTCOD
CAF 20SEC # DELAY FOR 20 SEC WHILE THE AGS
TC BANKCALL # DOWNLIST IS TRANSMITTED
CADR DELAYJOB
CA AGSWORD
TS DNLSTCOD # RETURN TO THE OLD DOWNLIST
CAF IMUSEBIT
MASK FLAGWRD0 # CHECK IMUSE FLAG.
CCS A
TC AGSEND # IMU IS BEING USED - DO NOT ZERO
CKSTALL CCS IMUCADR # CHECK FOR IMU USAGE WHICH AVOIDS THE
TCF +3 # IMUSE BIT: I.E., IMU COMPENSATION.
TCF +6 # FREE. GO AHEAD WITH THE IMU ZERO.
TCF +1
+3 CAF TEN # WAIT .1 SEC AND TRY AGAIN.
TC BANKCALL
CADR DELAYJOB
TCF CKSTALL
+6 TC BANKCALL # IMU IS NOT IN USE
CADR IMUZERO # SET IMU ZERO DISCRETE FOR 320 MSECS
TC BANKCALL # WAIT 3 SEC FOR COUNTERS TO INCREMENT
CADR IMUSTALL
TC AGSEND
AGSEND CAF V50N16
TC BANKCALL
CADR GOMARK3
TCF ENDEXT
TCF ENDEXT
TC ENDEXT
SCALEVEC VLOAD MXV
VATT1
REFSMMAT
VXSC VSL2
VSCALE
VAD VAD # THIS SECTION ROUNDS THE VECTOR, AND
AGSRND1 # CORRECTS FOR THE FACT THAT THE AGS
AGSRND2 # IS A 2 S COMPLIMENT MACHINE WHILE THE
RTB # LGC IS A 1 S COMPLIMENT MACHINE.
VECSGNAG
STOVL VATT1
## Page 221
RATT1
MXV VXSC
REFSMMAT
RSCALE
VSL8 VAD # AGAIN THIS SECTION ROUNDS. TWO VECTORS
AGSRND1 # ARE ADDED TO DEFEAT ALSIGNAG IN THE
VAD RTB # CASE OF A HIGH-ORDER ZERO COUPLED WITH
AGSRND2 # A LOW ORDER NEGATIVE PART.
VECSGNAG
LXA,1
VATT1
SXA,1 LXA,1
MPAC +1
VATT1 +2
SXA,1 LXA,1
MPAC +4
VATT1 +4
SXA,1 RVQ
MPAC +6
LAGSLIST = ONE
V01N14 VN 0114
V50N00A VN 5000
V00N25 EQUALS OCT31
V06N16 VN 0616
V00N34 EQUALS 34DEC
V50N16 VN 5016
TSCALE 2DEC 100 B-10 # CSEC TO SEC SCALE FACTOR
20SEC DEC 2000
RSCALE 2DEC 3.280839 B-3 # METERS TO FEET SCALE FACTOR
VSCALE 2DEC 3.280839 E2 B-9 # METERS/CS TO FEET/SEC SCALE FACTOR
AGSRND1 2OCT 0000060000
2OCT 0000060000
2OCT 0000060000
AGSRND2 2OCT 0000037777
2OCT 0000037777
2OCT 0000037777
SBANK= LOWSUPER # FOR SUBSEQUENT LOW 2CADRS.
