Source Code
|
These source-code files are part of a reconstructed copy of Skylark 048, the
Block II Command Module (CM) Apollo Guidance Computer (AGC) software for the
Skylab-2, Skylab-3, Skylab-4, and Apollo-Soyuz Test Project missions.
They have been created via disassembly of binary dumps of the original core rope
memory modules actually flown on Skylab-2, part numbers 2010802-541, 2010802-551,
2010802-561, 2010802-571, 2010802-581, and 2010802-591. Access to these modules
was provided by the New Mexico Museum of Space History, who we are much indebted to.
The source code for the Apollo 15, 16, and 17 software, Artemis 072, was used as
a starting point. Heavy use was made of TRW 4900.5-244, Programmed Guidance Equations
for Skylark Command Module Earth Orbital Program, dated 14 February 1972. This document
contains pseudocode of essentially all of Skylark, using original program labels which
have been copied for this source reconstruction.
Since only binary dumps (rather than listings) of Skylark are available as source material,
all comments and labels are approximate.
They have been taken from the Programmed Guidance Equations or other AGC programs where
possible, or, in some places, written from scratch to match what we believe would have
been in the original listing.
|
020007,000002: ## Copyright: Public domain.
020008,000003: ## Filename: P76.agc
020009,000004: ## Purpose: A section of Skylark revision 048.
020010,000005: ## It is part of the source code for the Apollo Guidance Computer (AGC)
020011,000006: ## for Skylab-2, Skylab-3, Skylab-4, and ASTP. No original listings of
020012,000007: ## this software are available; instead, this file was created via
020013,000008: ## disassembly of dumps of the core rope modules actually flown on
020014,000009: ## Skylab-2. Access to these modules was provided by the New Mexico
020015,000010: ## Museum of Space History.
020016,000011: ## Assembler: yaYUL
020017,000012: ## Contact: Ron Burkey <info@sandroid.org>.
020018,000013: ## Website: www.ibiblio.org/apollo/index.html
020019,000014: ## Mod history: 2024-02-20 MAS Created from Artemis 072.
020020,000015: ## 2024-03-05 MAS Updated for Skylark 48.
020021,000016:
020022,000017: # 1) PROGRAM NAME - TARGET DELTA V PROGRAM (P76).
020023,000018: # 2) FUNCTIONAL DESCRIPTION - UPON ENTRY BY ASTRONAUT ACTION, P76 FLASHES DSKY REQUESTS TO THE ASTRONAUT
020024,000019: # TO PROVIDE VIA DSKY (1) THE DELTA V TO BE APPLIED TO THE OTHER VEHICLE STATE VECTOR AND (2) THE
020025,000020: # TIME (TIG) AT WHICH THE OTHER VEHICLE VELOCITY WAS CHANGED BY EXECUTION OF A THRUSTING MANEUVER. THE
020026,000021: # OTHER VEHICLE STATE VECTOR IS INTEGRATED TO TIG AND UPDATED BY THE ADDITION OF DELTA V (DELTA V HAVING
020027,000022: # BEEN TRANSFORMED FROM LV TO REF COSYS). USING INTEGRVS, THE PROGRAM THEN INTEGRATES THE OTHER
020028,000023: # VEHICLE STATE VECTOR TO THE STATE VECTOR OF THIS VEHICLE, THUS INSURING THAT THE W-MATRIX AND BOTH VEHICLE
020029,000024: # STATES CORRESPOND TO THE SAME TIME.
020030,000025: # 3) ERASABLE INITIALIZATION REQUIRED - NONE.
020031,000026: # 4) CALLING SEQUENCES AND EXIT MODES - CALLED BY ASTRONAUT REQUEST THRU DSKY V 37 E 76 E.
020032,000027: # EXITS BY TCF ENDOFJOB.
020033,000028: # 5) OUTPUT - OTHER VEHICLE STATE VECTOR INTEGRATED TO TIG AND INCREMENTED BY DELTA V IN REF COSYS.
020034,000029: # THE PUSHLIST CONTAINS THE MATRIX BY WHICH THE INPUT DELTA V MUST BE POST-MULTIPLIED TO CONVERT FROM LV
020035,000030: # TO REF COSYS.
020036,000031: # 6) DEBRIS - OTHER VEHICLE STATE VECTOR.
020037,000032: # 7) SUBROUTINES CALLED - BANKCALL,GOXDSPF,CSMPREC (OR LEMPREC),ATOPCSM (OR ATOPLEM),INTSTALL,INTWAKE, PHASCHNG
020038,000033: # INTPRET, INTEGRVS, AND MINIRECT.
020039,000034: # 8) FLAG USE - MOONFLAG,CMOONFLAG,INTYPFLG,RASFLAG, AND MARKCTR.
020040,000035:
020041,000036: 05,2000 SETLOC P76LOC
020042,000037: 05,2000 BANK
020043,000038:
020044,000039: 05,3172 COUNT* $$/P7677
020045,000040: 05,3172 E7,1412 EBANK= TIG
020046,000041:
020047,000042: 05,3172 00006 P77 EXTEND
020048,000043: 05,3173 31450 DCA NOMTIG
020049,000044: 05,3174 53413 DXCH TIG
020050,000045:
020051,000046: 05,3175 35041 CAF V06N33
020052,000047: 05,3176 04647 TC BANKCALL # AND WAIT FOR KEYBOARD ACTION
020053,000048: 05,3177 20623 CADR GOFLASH
020054,000049: 05,3200 13306 TCF ENDP76
020055,000050: 05,3201 03203 TC +2 # PROCEED
020056,000051: 05,3202 03175 TC -5 # STORE DATA AND REPEAT FLASHING
020057,000052: 05,3203 34603 CAF V06N81 # FLASH V06 N81
020058,000053: 05,3204 04647 TC BANKCALL # AND WAIT FOR KEYBOARD ACTION.
020059,000054: 05,3205 20623 CADR GOFLASH
020060,000055: 05,3206 13306 TCF ENDP76
020061,000056: 05,3207 03211 TC +2
020062,000057: 05,3210 03203 TC -5 # STORE DATA AND REPEAT FLASHING
020063,000058: 05,3211 06006 TC INTPRET # RETURN TO INTERPRETIVE CODE
020064,000059: 05,3212 43145 DLOAD SET # SET D(MPAC)=TIG IN CSEC B28
020065,000060: 05,3213 03413 TIG
020066,000061: 05,3214 01076 NODOFLAG # DISALLOW V37
020067,000062: 05,3215 34041 STCALL TDEC1
020068,000063: 05,3216 11400 CSMPREC
020069,000064: 05,3217 53575 COMPMAT VLOAD UNIT
020070,000065: 05,3220 00001 RATT
020071,000066: 05,3221 77676 VCOMP # U(-R)
020072,000067: 05,3222 00031 STORE 24D # U(-R) TO 24D
020073,000068: 05,3223 53435 VXV UNIT # U(-R)XV = U(VXR)
020074,000069: 05,3224 00007 VATT
020075,000070: 05,3225 00023 STORE 18D
020076,000071: 05,3226 53435 VXV UNIT # U(VXR)XU(-R) = U((RXV)XR)
020077,000072: 05,3227 00031 24D
020078,000073: 05,3230 24015 STOVL 12D
020079,000074: 05,3231 03405 DELVLVC # FROM CSM
020080,000075: 05,3232 76505 DVTRANS VXM VSL1 # V(MPAC)=DELTA-V IN REFCOSYS
020081,000076: 05,3233 00015 12D
020082,000077: 05,3234 77655 VAD
020083,000078: 05,3235 00007 VATT
020084,000079: 05,3236 00007 STORE 6 # V(PD6)=VATT + DELTA V
020085,000080: 05,3237 77624 CALL # PREVENT WOULD-BE USER OF ORBITAL
020086,000081: 05,3240 11720 INTSTALL # INTEG FROM INTERFERING WITH UPDATING
020087,000082: 05,3241 77775 VLOAD
020088,000083: 05,3242 00007 6
020089,000084: 05,3243 25543 STOVL VCV
020090,000085: 05,3244 00001 RATT
020091,000086: 05,3245 15535 STODL RCV
020092,000087: 05,3246 03413 TIG
020093,000088: 05,3247 01517 STORE TET
020094,000089: 05,3250 71214 CLEAR DLOAD
020095,000090: 05,3251 01673 INTYPFLG
020096,000091: 05,3252 01571 TETTHIS
020097,000092: 05,3253 34041 INTOTHIS STCALL TDEC1
020098,000093: 05,3254 11444 INTEGRVS
020099,000094: 05,3255 77624 CALL
020100,000095: 05,3256 11720 INTSTALL
020101,000096: 05,3257 77775 VLOAD
020102,000097: 05,3260 00017 RATT1
020103,000098: 05,3261 01503 STORE RRECT
020104,000099: 05,3262 15535 STODL RCV
020105,000100: 05,3263 00015 TAT
020106,000101: 05,3264 25517 STOVL TET
020107,000102: 05,3265 00025 VATT1
020108,000103: 05,3266 77624 CALL
020109,000104: 05,3267 23452 MINIRECT
020110,000105: 05,3270 77776 EXIT
020111,000106: 05,3271 05415 TC PHASCHNG
020112,000107: 05,3272 04024 OCT 04024
020113,000108:
020114,000109: 05,3273 06006 TC INTPRET
020115,000110: 05,3274 45014 SET CALL
020116,000111: 05,3275 05062 REINTFLG
020117,000112: 05,3276 11305 ATOPCSM
020118,000113: 05,3277 77624 CALL
020119,000114: 05,3300 11727 INTWAKE0 # PERMIT USE OF ORBITAL INTEGRATION
020120,000115: 05,3301 77414 OUT CLEAR EXIT # ALLOW V37, NO NEED TO CLEAR NODOFLAG AT
020121,000116: 05,3302 01276 NODOFLAG # ENDP76 SINCE FLAG NOT SET WHEN DISPLAY
020122,000117: # RESPONSES TRANSFER THERE FROM P76+.
020123,000118: 05,3303 37702 CAF NEGONE
020124,000119: 05,3304 55702 TS MRKBUF1
020125,000120: 05,3305 14105 TCF MNKGOPOO
020126,000121:
020127,000122: 05,3306 37702 ENDP76 CAF NEGONE
020128,000123: 05,3307 55702 TS MRKBUF1 # INVALIDATE MARK BUFFER
020129,000124:
020130,000125: 05,3310 14103 TCF GOTOPOOH
End of include-file P76.agc. Parent file is MAIN.agc