Source Code
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These source code files are a reconstruction of Sundance, the Apollo 9 LM (Lunar Module) AGC
(Apollo Guidance Computer) flight software, created from binary dumps of original core rope
program modules, as follows:
Since only binary dumps (rather than listings) of Sundance are available as source material, all comments and labels are approximate. They have been taken from other AGC programs where possible, or, in some places, written from scratch to match what we believe would have been in the original listing. |
031360,000002: ## Copyright: Public domain.
031361,000003: ## Filename: THROTTLE_CONTROL_ROUTINES.agc
031362,000004: ## Purpose: A section of a reconstructed, mixed version of Sundance
031363,000005: ## It is part of the reconstructed source code for the Lunar
031364,000006: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 9.
031365,000007: ## No original listings of this program are available;
031366,000008: ## instead, this file was created via disassembly of dumps
031367,000009: ## of various revisions of Sundance core rope modules.
031368,000010: ## Assembler: yaYUL
031369,000011: ## Contact: Ron Burkey <info@sandroid.org>.
031370,000012: ## Website: www.ibiblio.org/apollo/index.html
031371,000013: ## Mod history: 2020-06-17 MAS Created from Luminary 69.
031372,000014:
031373,000015: ## Sundance 292
031374,000016:
031375,000017: 31,2235 BANK 31
031376,000018: 31,2000 SETLOC FTHROT
031377,000019: 31,2000 BANK
031378,000020: 31,2235 E7,1417 EBANK= PIF
031379,000021: 31,2235 COUNT* $$/THROT
031380,000022:
031381,000023: # * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
031382,000024: # HERE FC, DESIRED THRUST, AND FP, PRESENT THRUST, UNWEIGHTED, ARE COMPUTED.
031383,000025:
031384,000026: 31,2235 31245 THROTTLE CA ABDELV # COMPUTE PRESENT ACCELERATION IN UNITS OF
031385,000027: 31,2236 00006 EXTEND # 2(-4) M/CS/CS, SAVING SERVICER TROUBLE
031386,000028: 31,2237 72414 MP /AF/CNST
031387,000029: 31,2240 00006 +3 EXTEND
031388,000030: 31,2241 23600 QXCH RTNHOLD
031389,000031: 31,2242 02373 AFDUMP TC MASSMULT
031390,000032: 31,2243 53553 DXCH FP # FP = PRESENT THRUST
031391,000033: 31,2244 00006 EXTEND
031392,000034: 31,2245 31570 DCA /AFC/
031393,000035: 31,2246 02373 TC MASSMULT
031394,000036: 31,2247 53551 DXCH FCODD # FCODD = WHAT IT IS GOING TO GET
031395,000037:
031396,000038: # IF IT HAS BEEN LESS THAN 3 SECONDS SINCE THE LAST THROTTLING, AUGMENT FP USING THE FWEIGHT CALCULATED THEN.
031397,000039:
031398,000040: 31,2250 41604 CS TTHROT # THIS CODING ASSUMES A FLATOUT WITHIN
031399,000041: 31,2251 60025 AD TIME1 # 80 SECONDS BEFORE FIRST THROTTLE CALL
031400,000042: 31,2252 75006 MASK POSMAX
031401,000043: 31,2253 40000 COM
031402,000044: 31,2254 65052 AD 3SECS
031403,000045: 31,2255 00006 EXTEND
031404,000046: 31,2256 62262 BZMF WHERETO # BRANCH IF (TIME1-TTHROT +1) > 3 SECONDS
031405,000047: 31,2257 00006 EXTEND
031406,000048: 31,2260 31602 DCA FWEIGHT
031407,000049: 31,2261 21553 DAS FP
031408,000050:
031409,000051: # THIS LOGIC DETERMINES THE THROTTLING IN THE REGION 10% - 94%. THE MANUAL THROTTLE, NOMINALLY SET AT
031410,000052: # MINIMUM BY ASTRONAUT OR MISSION CONTROL PROGRAMS, PROVIDES THE LOWER BOUND. A STOP IN THE THROTTLE HARDWARE
031411,000053: # PROVIDES THE UPPER.
031412,000054:
031413,000055: 31,2262 45030 WHERETO CS ZERO # INITIALIZE PIFPSET
031414,000056: 31,2263 55577 TS PIFPSET
031415,000057: 31,2264 42407 CS HIGHCRIT
031416,000058: 31,2265 61657 AD FCOLD
031417,000059: 31,2266 00006 EXTEND
031418,000060: 31,2267 62301 BZMF LOWFCOLD # BRANCH IF FCOLD < OR = HIGHCRIT
031419,000061: 31,2270 42410 CS LOWCRIT
031420,000062: 31,2271 61550 AD FCODD
031421,000063: 31,2272 00006 EXTEND
031422,000064: 31,2273 62276 BZMF FCOMPSET # BRANCH IF FC < OR = LOWCRIT
031423,000065: 31,2274 31552 CA FP # SEE NOTE 1
031424,000066: 31,2275 12306 TCF FLATOUT1
031425,000067:
031426,000068: 31,2276 42405 FCOMPSET CS FMAXODD # SEE NOTE 2
031427,000069: 31,2277 61552 AD FP
031428,000070: 31,2300 12310 TCF FLATOUT2
031429,000071:
031430,000072: 31,2301 42407 LOWFCOLD CS HIGHCRIT
031431,000073: 31,2302 61550 AD FCODD
031432,000074: 31,2303 00006 EXTEND
031433,000075: 31,2304 62311 BZMF DOPIF # BRANCH IF FC < OR = HIGHCRIT
031434,000076:
031435,000077: 31,2305 32406 CA FMAXPOS # NO: THROTTLE-UP
031436,000078: 31,2306 53551 FLATOUT1 DXCH FCODD
031437,000079: 31,2307 35020 CA FEXTRA
031438,000080: 31,2310 55577 FLATOUT2 TS PIFPSET
031439,000081:
031440,000082: # NOTE 1 FC IS SET EQUAL TO FP SO PIF WILL BE ZERO. THIS IS DESIRABLE
031441,000083: # AS THERE IS ACTUALLY NO THROTTLE CHANGE.
031442,000084:
031443,000085: # NOTE2 HERE, SINCE WE ARE ABOUT TO RETURN TO THE THROTTLEABLE REGION
031444,000086: # (BELOW 55%) THE QUANTITY -(FMAXODD-FP) IS COMPUTED AND PUT
031445,000087: # INTO PIFPSET TO COMPENSATE FOR THE DIFFERENCE BETWEEN THE
031446,000088: # NUMBER OF BITS CORRESPONDING TO FULL THROTTLE (FMAXODD) AND THE
031447,000089: # NUMBER CORRESPONDING TO ACTUAL THRUST (FP). THUS THE TOTAL
031448,000090: # THROTTLE COMMAND PIF = FC - FP - (FMAXODD - FP) = FC - FMAXODD.
031449,000091:
031450,000092: 31,2311 03562 DOPIF TC FASTCHNG # RESTART PROTECTION
031451,000093: 31,2312 00006 EXTEND
031452,000094: 31,2313 31551 DCA FCODD
031453,000095: 31,2314 55657 TS FCOLD
031454,000096: 31,2315 53420 DXCH PIF
031455,000097: 31,2316 00006 EXTEND
031456,000098: 31,2317 41553 DCS FP
031457,000099: 31,2320 21420 DAS PIF # PIF = FC - FP, NEVER EQUALS +0
031458,000100:
031459,000101: 31,2321 31417 DOIT CA PIF
031460,000102: 31,2322 61577 AD PIFPSET # ADD IN PIFPSET, WITHOUT CHANGING PIF
031461,000103: 31,2323 55603 TS PSEUDO55
031462,000104: 31,2324 54055 TS THRUST
031463,000105: 31,2325 35023 CAF BIT4
031464,000106: 31,2326 00006 EXTEND
031465,000107: 31,2327 05014 WOR CHAN14
031466,000108: 31,2330 30025 CA TIME1
031467,000109: 31,2331 55604 TS TTHROT
031468,000110:
031469,000111: # SINCE /AF/ IS NOT AN INSTANTANEOUS ACCELERATION, BUT RATHER AN "AVERAGE" OF THE ACCELERATION LEVELS DURING
031470,000112: # THE PRECEEDING PIPA INTERVAL, AND SINCE FP IS COMPUTED DIRECTLY FROM /AF/, FP IN ORDER TO CORRESPOND TO THE
031471,000113: # ACTUAL THRUST LEVEL AT THE END OF THE INTERVAL MUST BE WEIGHTED BY
031472,000114:
031473,000115: # PIF(PPROCESS + TL) PIF /PIF/
031474,000116: # FWEIGHT = ------------------ + -------------
031475,000117: # PGUID 2 PGUID FRATE
031476,000118:
031477,000119: # WHERE PPROCESS IS THE TIME BETWEEN PIPA READING AND THE START OF THROTTLING, PGUID IS THE GUIDANCE PERIOD, AND
031478,000120: # FRATE IS THE THROTTLING RATE (32 UNITS PER CENTISECOND). PGUID IS ASSUMED TO BE 2 SECONDS. THE "TL" IN THE
031479,000121: # FIRST TERM REPRESENTS THE ENGINE'S RESPONSE LAG. HERE FWEIGHT IS COMPUTED FOR USE NEXT PASS.
031480,000122:
031481,000123: 31,2332 35053 CA 4SECS
031482,000124: 31,2333 54002 TS Q
031483,000125: 31,2334 41234 CS PIPTIME +1 # TIME OF LAST PIPA READING
031484,000126: 31,2335 60025 AD TIME1
031485,000127: 31,2336 62412 AD THROTLAG # COMPENSATE FOR ENGINE RESPONSE LAG
031486,000128: 31,2337 74371 MASK LOW8 # MAKE SURE SMALL AND POSITIVE
031487,000129: 31,2340 22007 ZL
031488,000130: 31,2341 00006 EXTEND
031489,000131: 31,2342 10002 DV Q
031490,000132: 31,2343 00006 EXTEND
031491,000133: 31,2344 71417 MP PIF
031492,000134: 31,2345 60000 DOUBLE
031493,000135: 31,2346 53602 DXCH FWEIGHT
031494,000136: 31,2347 32413 CA 2.PG.FRT
031495,000137: 31,2350 54002 TS Q
031496,000138: 31,2351 11417 CCS PIF
031497,000139: 31,2352 65026 AD ONE
031498,000140: 31,2353 12355 TCF +2
031499,000141: 31,2354 65026 AD ONE
031500,000142: 31,2355 00006 EXTEND
031501,000143: 31,2356 71417 MP PIF
031502,000144: 31,2357 00006 EXTEND
031503,000145: 31,2360 10002 DV Q
031504,000146: 31,2361 22007 ZL
031505,000147: 31,2362 21602 DAS FWEIGHT
031506,000148:
031507,000149: 31,2363 01600 THDUMP TC RTNHOLD
031508,000150:
031509,000151: # FLATOUT THROTTLES UP THE DESCENT ENGINE, AND IS CALLED AS A BASIC SUBROUTINE.
031510,000152:
031511,000153: 31,2364 35012 FLATOUT CAF BIT13 # 4096 PULSES
031512,000154: 31,2365 55577 WHATOUT TS PIFPSET # USE PIFPSET SO FWEIGHT WILL BE ZERO
031513,000155: 31,2366 45030 CS ZERO
031514,000156: 31,2367 55417 TS PIF
031515,000157: 31,2370 00006 EXTEND
031516,000158: 31,2371 23600 QXCH RTNHOLD
031517,000159: 31,2372 12321 TCF DOIT
031518,000160:
031519,000161: # MASSMULT SCALES ACCELERATION, ARRIVING IN A AND L IN UNITS OF 2(-4) M/CS/CS, TO FORCE IN PULSE UNITS.
031520,000162:
031521,000163: 31,2373 00006 MASSMULT EXTEND
031522,000164: 31,2374 22130 QXCH BUF
031523,000165: 31,2375 00006 EXTEND
031524,000166: 31,2376 71243 MP MASS # LEAVES ODDLY SCALED FORCE IN A AND L
031525,000167: 31,2377 52155 DXCH MPAC
031526,000168: 31,2400 07057 TC DMP # LEAVES PROPERLY SCALED FORCE IM MPAC
031527,000169: 31,2401 02415 ADRES SCALEFAC
031528,000170: 31,2402 52156 DXCH MPAC +1
031529,000171: 31,2403 00130 TC BUF
031530,000172:
031531,000173: # CONSTANTS:-
031532,000174:
031533,000175: 31,2404 07452 FMAXMAX DEC +3882 B-14
031534,000176: 31,2405 07432 FMAXODD DEC +3866 B-14 # THROTTLE SATURATION THRESHOLD
031535,000177: 31,2406 07100 FMAXPOS DEC +3648 B-14 # FMAX 43245 NEWTONS
031536,000178: 31,2407 04616 HIGHCRIT DEC 2446 B-14
031537,000179: 31,2410 04127 LOWCRIT DEC 2135 B-14
031538,000180: 31,2411 5020 FEXTRA = BIT7
031539,000181: 31,2411 00666 DEC438 DEC 438 B-14
031540,000182: 31,2412 00024 THROTLAG DEC 20 B-14 # EMPIRICALLY DETERMINED THROTTLE LAG TIME
031541,000183: 31,2413 31000 2.PG.FRT DEC 12800 B-14
031542,000184: 31,2414 04143 /AF/CNST DEC .13107
031543,000185: 31,2415 00317 31157 SCALEFAC 2DEC 51.947 B-12 # SCALES A (AT 2(-4) M/CS/CS) TIMES MASS
031544,000186: # (AT 2(16) KGS. ) TO PULSE UNITS.
031545,000187:
031546,000188: # * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
End of include-file THROTTLE_CONTROL_ROUTINES.agc. Parent file is MAIN.agc