Source Code
|
These source-code files are part of a reconstructed copy of Luminary 173, the
second (unflown) release of the Apollo 14 Lunar Module (LM) Apollo Guidance
Computer (AGC) software.
The reconstruction began with reconstructed source code for Luminary 178. Changes
between revision 173 and 178 were backed out, as described by Luminary memo 167
(revision 1). The reconstruction was verified by matching memory-bank checksums
to those listed in drawing 2021152N. Note that page numbers in the reconstructed
code match those for the baseline log section mentioned in each file's changelog;
the page numbers for a real Luminary 173 listing would be different.
Comments from the original source code are prefixed with a single '#' symbol,
whereas comments added later are prefixed by "##" or "###". Report any errors
noted by creating an
issue report at the Virtual AGC
project's GitHub repository.
|
033808,000002: ## Copyright: Public domain.
033809,000003: ## Filename: THROTTLE_CONTROL_ROUTINES.agc
033810,000004: ## Purpose: A section of Luminary revision 173.
033811,000005: ## It is part of the reconstructed source code for the second
033812,000006: ## (unflown) release of the flight software for the Lunar
033813,000007: ## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 14.
033814,000008: ## The code has been recreated from a reconstructed copy of
033815,000009: ## Luminary 178, as well as Luminary memo 167 (revision 1).
033816,000010: ## It has been adapted such that the resulting bugger words
033817,000011: ## exactly match those specified for Luminary 173 in NASA
033818,000012: ## drawing 2021152N, which gives relatively high confidence
033819,000013: ## that the reconstruction is correct.
033820,000014: ## Reference: pp. 779-783
033821,000015: ## Assembler: yaYUL
033822,000016: ## Contact: Ron Burkey <info@sandroid.org>.
033823,000017: ## Website: www.ibiblio.org/apollo/index.html
033824,000018: ## Mod history: 2019-09-18 MAS Created from Luminary 178.
033825,000019:
|
|
Page 789
|
033827,000021: 31,2144 BANK 31
033828,000022:
033829,000023: 31,2000 SETLOC FTHROT
033830,000024:
033831,000025: 31,2000 BANK
033832,000026:
033833,000027: 31,2144 E7,1612 EBANK= PIF
033834,000028:
033835,000029: 31,2144 COUNT* $$/THROT
033836,000030: # * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
033837,000031: # HERE FC, DESIRED THRUST, AND FP, PRESENT THRUST, UNWEIGHTED, ARE COMPUTED.
033838,000032:
033839,000033: 31,2144 31245 THROTTLE CA ABDELV # COMPUTE PRESENT ACCELERATION IN UNITS OF
033840,000034: 31,2145 00006 EXTEND # 2(-4) M/CS/CS, SAVING SERVICER TROUBLE
033841,000035: 31,2146 72363 MP /AF/CNST
033842,000036: 31,2147 00006 +3 EXTEND
033843,000037: 31,2150 23607 QXCH RTNHOLD
033844,000038: 31,2151 02344 AFDUMP TC MASSMULT
033845,000039: 31,2152 53470 DXCH FP # FP = PRESENT THRUST
033846,000040: 31,2153 00006 EXTEND
033847,000041: 31,2154 31464 DCA /AFC/
033848,000042: 31,2155 02344 TC MASSMULT
033849,000043: 31,2156 00004 INHINT # PREVENT A DOWNRUPT
033850,000044: 31,2157 55615 TS FC # FC = THRUST DESIRED BY GUIDANCE
033851,000045: 31,2160 53466 DXCH FCODD # FCODD = WHAT IT IS GOING TO GET
033852,000046:
033853,000047:
033854,000048: 31,2161 00006 EXTEND
033855,000049: 31,2162 31234 DCA PIPTIME
033856,000050: 31,2163 53753 DXCH GTCTIME # DOWNLINK TIME AGREEMENT
033857,000051: 31,2164 00003 RELINT
033858,000052:
033859,000053: # COMPUTE DESIRED THRUST FOR DISPLAY AS A PERCENTAGE OF 10,500 POUNDS
033860,000054:
033861,000055: 31,2165 32365 CAF 4FMAXNOM # MOVE 4FMAXNOM TO ERASABLE FOR DV BELOW
033862,000056: 31,2166 54002 TS Q
033863,000057: 31,2167 31615 CA FC
033864,000058: 31,2170 72364 MASK OCT17777 # FOR SAFETY
033865,000059: 31,2171 00006 EXTEND
033866,000060: 31,2172 10002 DV Q
033867,000061: 31,2173 00006 EXTEND
033868,000062: 31,2174 75003 MP 4SECS
033869,000063: 31,2175 55750 TS THRDISP # FOR DISPLAY IN N92
033870,000064:
033871,000065: # IF IT HAS BEEN LESS THAN 3 SECONDS SINCE THE LAST THROTTLING, AUGMENT FP USING THE FWEIGHT CALCULATED THEN.
033872,000066:
033873,000067: 31,2176 41617 CS TTHROT # THIS CODING ASSUMES A FLATOUT WITHIN
|
|
Page 790
|
033875,000069: 31,2177 60025 AD TIME1 # 80 SECONDS BEFORE FIRST THROTTLE CALL
033876,000070: 31,2200 74733 MASK POSMAX
033877,000071: 31,2201 40000 COM
033878,000072: 31,2202 65002 AD 3SECS
033879,000073: 31,2203 00006 EXTEND
033880,000074: 31,2204 62210 BZMF WHERETO # BRANCH IF (TIME1-TTHROT +1) > 3 SECONDS
033881,000075: 31,2205 00006 EXTEND
033882,000076: 31,2206 31611 DCA FWEIGHT
033883,000077: 31,2207 21470 DAS FP
033884,000078:
033885,000079:
033886,000080: # THIS LOGIC DETERMINES THE THROTTLING IN THE REGION 10% - 94%. THE MANUAL THROTTLE, NOMINALLY SET AT
033887,000081: # MINIMUM BY ASTRONAUT OR MISSION CONTROL PROGRAMS, PROVIDES THE LOWER BOUND. A STOP IN THE THROTTLE HARDWARE
033888,000082: # PROVIDES THE UPPER.
033889,000083:
033890,000084: 31,2210 35014 WHERETO CA EBANK5 # INITIALIZE L*WCR*T AND H*GHCR*T FROM
033891,000085: 31,2211 54003 TS EBANK # PAD LOADED ERASABLES IN W-MATRIX
033892,000086: 31,2212 E5,1472 EBANK= LOWCRIT
033893,000087: 31,2212 00006 EXTEND
033894,000088: 31,2213 31473 DCA LOWCRIT
033895,000089: 31,2214 52131 DXCH L*WCR*T
033896,000090: 31,2215 35016 CA EBANK7
033897,000091: 31,2216 54003 TS EBANK
033898,000092: 31,2217 E7,1612 EBANK= PIF
033899,000093: 31,2217 44755 CS ZERO # INITIALIZE PIFPSET
033900,000094: 31,2220 55606 TS PIFPSET
033901,000095: 31,2221 40131 CS H*GHCR*T
033902,000096: 31,2222 61620 AD FCOLD
033903,000097: 31,2223 00006 EXTEND
033904,000098: 31,2224 62236 BZMF LOWFCOLD # BRANCH IF FCOLD < OR = HIGHCRIT
033905,000099: 31,2225 40130 CS L*WCR*T
033906,000100: 31,2226 61465 AD FCODD
033907,000101: 31,2227 00006 EXTEND
033908,000102: 31,2230 62233 BZMF FCOMPSET # BRANCH IF FC < OR = LOWCRIT
033909,000103: 31,2231 31467 CA FP # SEE NOTE 1
033910,000104: 31,2232 12243 TCF FLATOUT1
033911,000105:
033912,000106: 31,2233 42002 FCOMPSET CS FMAXODD # SEE NOTE 2
033913,000107: 31,2234 61467 AD FP
033914,000108: 31,2235 12245 TCF FLATOUT2
033915,000109:
033916,000110: 31,2236 40131 LOWFCOLD CS H*GHCR*T
033917,000111: 31,2237 61465 AD FCODD
033918,000112: 31,2240 00006 EXTEND
033919,000113: 31,2241 62246 BZMF DOPIF # BRANCH IF FC < OR = HIGHCRIT
033920,000114:
033921,000115: 31,2242 32003 CA FMAXPOS # NO: THROTTLE-UP
033922,000116: 31,2243 53466 FLATOUT1 DXCH FCODD
033923,000117: 31,2244 34737 CA FEXTRA
|
|
Page 791
|
033925,000119: 31,2245 55606 FLATOUT2 TS PIFPSET
033926,000120:
033927,000121: # NOTE 1 FC IS SET EQUAL TO FP SO PIF WILL BE ZERO. THIS IS DESIRABLE
033928,000122: # AS THERE IS ACTUALLY NO THROTTLE CHANGE.
033929,000123:
033930,000124: # NOTE 2 HERE, SINCE WE ARE ABOUT TO RETURN TO THE THROTTLEABLE REGION
033931,000125: # (BELOW 55%) THE QUANTITY -(FMAXODD - FP) IS COMPUTED AND PUT
033932,000126: # INTO PIFPSET TO COMPENSATE FOR THE DIFFERENCE BETWEEN THE
033933,000127: # NUMBER OF BITS CORRESPONDING TO FULL THROTTLE (FMAXODD) AND THE
033934,000128: # NUMBER CORRESPONDING TO ACTUAL THRUST (FP). THUS THE TOTAL
033935,000129: # THROTTLE COMMAND PIF = FC - FP -(FMAXODD - FP) = FC - FMAXODD.
033936,000130:
033937,000131: 31,2246 03751 DOPIF TC FASTCHNG
033938,000132: 31,2247 00006 EXTEND
033939,000133: 31,2250 31466 DCA FCODD
033940,000134: 31,2251 55620 TS FCOLD
033941,000135: 31,2252 53613 DXCH PIF
033942,000136: 31,2253 00006 EXTEND
033943,000137: 31,2254 41470 DCS FP
033944,000138: 31,2255 21613 DAS PIF # PIF = FC - FP, NEVER EQUALS +0
033945,000139:
033946,000140:
033947,000141: 31,2256 31612 DOIT CA PIF
033948,000142: 31,2257 61606 AD PIFPSET # ADD IN PIFPSET, WITHOUT CHANGING PIF
033949,000143: 31,2260 55614 TS PSEUDO55
033950,000144: 31,2261 54055 TS THRUST
033951,000145: 31,2262 34750 CAF BIT4
033952,000146: 31,2263 00006 EXTEND
033953,000147: 31,2264 05014 WOR CHAN14
033954,000148: 31,2265 30025 CA TIME1
033955,000149: 31,2266 55617 TS TTHROT
033956,000150:
033957,000151: # SINCE /AF/ IS NOT AN INSTANTANEOUS ACCELERATION, BUT RATHER AN "AVERAGE" OF THE ACCELERATION LEVELS DURING
033958,000152: # THE PRECEEDING PIPA INTERVAL, AND SINCE FP IS COMPUTED DIRECTLY FROM /AF/, FP IN ORDER TO CORRESPOND TO THE
033959,000153: # ACTUAL THRUST LEVEL AT THE END OF THE INTERVAL MUST BE WEIGHTED BY
033960,000154:
033961,000155: # PIF(PPROCESS + TL) PIF /PIF/
033962,000156: # FWEIGHT = ------------------ + -------------
033963,000157: # PGUID 2 PGUID FRATE
033964,000158:
033965,000159: # WHERE PPROCESS IS THE TIME BETWEEN PIPA READING AND THE START OF THROTTLING, PGUID IS THE GUIDANCE PERIOD, AND
033966,000160: # FRATE IS THE THROTTLING RATE (32 UNITS PER CENTISECOND). PGUID IS EITHER 1 OR 2 SECONDS. THE "TL" IN THE
033967,000161: # FIRST TERM REPRESENTS THE ENGINE'S RESPONSE LAG. HERE FWEIGHT IS COMPUTED FOR USE NEXT PASS.
033968,000162:
033969,000163: 31,2267 31762 CA THISTPIP +1 # INITIALIZE FWEIGHT COMP AS IF FOR P66
033970,000164: 31,2270 54130 TS BUF
033971,000165:
033972,000166: 31,2271 41010 CS MODREG # ARE WE IN FACT IN P66?
033973,000167: 31,2272 62454 AD DEC66
033974,000168: 31,2273 00006 EXTEND
|
|
Page 792
|
033976,000170: 31,2274 12301 BZF FWCOMP # YES
033977,000171:
033978,000172: 31,2275 31234 CA PIPTIME +1 # NO: INITIALIZE FOR TWO SECOND PERIOD
033979,000173: 31,2276 54130 TS BUF
033980,000174: 31,2277 35003 CAF 4SECS
033981,000175: 31,2300 12302 TCF FWCOMP +1
033982,000176:
033983,000177: 31,2301 35000 FWCOMP CAF 2SECS
033984,000178: 31,2302 54002 +1 TS Q
033985,000179: 31,2303 00006 EXTEND
033986,000180: 31,2304 74746 MP BIT6
033987,000181: 31,2305 22131 LXCH BUF +1
033988,000182: 31,2306 40130 CS BUF # TIME OF LAST PIPA READING.
033989,000183: 31,2307 60025 AD TIME1
033990,000184: 31,2310 62004 AD THROTLAG # COMPENSATE FOR ENGINE RESPONSE LAG
033991,000185: 31,2311 74357 MASK LOW8 # MAKE SURE SMALL AND POSITIVE
033992,000186: 31,2312 22007 ZL
033993,000187: 31,2313 00006 EXTEND
033994,000188: 31,2314 10002 DV Q
033995,000189: 31,2315 00006 EXTEND
033996,000190: 31,2316 71612 MP PIF
033997,000191: 31,2317 60000 DOUBLE
033998,000192: 31,2320 53611 DXCH FWEIGHT
033999,000193: 31,2321 11612 CCS PIF
034000,000194: 31,2322 64753 AD ONE
034001,000195: 31,2323 12325 TCF +2
034002,000196: 31,2324 64753 AD ONE
034003,000197: 31,2325 00006 EXTEND
034004,000198: 31,2326 71612 MP PIF
034005,000199: 31,2327 00006 EXTEND
034006,000200: 31,2330 10131 DV BUF +1
034007,000201: 31,2331 22007 ZL
034008,000202: 31,2332 21611 DAS FWEIGHT
034009,000203:
034010,000204:
034011,000205: 31,2333 01607 THDUMP TC RTNHOLD
034012,000206:
034013,000207:
034014,000208: # FLATOUT THROTTLES UP THE DESCENT ENGINE, AND IS CALLED AS A BASIC SUBROUTINE.
034015,000209:
034016,000210: 31,2334 34737 FLATOUT CAF BIT13 # 4096 PULSES
034017,000211: 31,2335 55606 WHATOUT TS PIFPSET # USE PIFPSET SO FWEIGHT WILL BE ZERO
034018,000212: 31,2336 44755 CS ZERO
034019,000213: 31,2337 55620 TS FCOLD
034020,000214: 31,2340 55612 TS PIF
034021,000215: 31,2341 00006 EXTEND
034022,000216: 31,2342 23607 QXCH RTNHOLD
034023,000217: 31,2343 12256 TCF DOIT
034024,000218:
|
|
Page 793
|
034026,000220: # MASSMULT SCALES ACCELERATION, ARRIVING IN A AND L IN UNITS OF 2(-4) M/CS/CS, TO FORCE IN PULSE UNITS.
034027,000221:
034028,000222: 31,2344 00006 MASSMULT EXTEND
034029,000223: 31,2345 22130 QXCH BUF
034030,000224: 31,2346 52155 DXCH MPAC
034031,000225: 31,2347 07106 TC DMP
034032,000226: 31,2350 01243 ADRES MASS
034033,000227: 31,2351 07106 TC DMP # LEAVES PROPERLY SCALED FORCE IM MPAC
034034,000228: 31,2352 02005 ADRES SCALEFAC
034035,000229: 31,2353 07262 TC TPAGREE
034036,000230: 31,2354 30154 CA MPAC
034037,000231: 31,2355 00006 EXTEND
034038,000232: 31,2356 12361 BZF +3
034039,000233: 31,2357 34733 CAF POSMAX
034040,000234: 31,2360 00130 TC BUF
034041,000235: 31,2361 52156 DXCH MPAC +1
034042,000236: 31,2362 00130 TC BUF
034043,000237:
034044,000238:
034045,000239: # CONSTANTS:-
034046,000240:
034047,000241: 31,2363 4737 FEXTRA = BIT13 # FEXT +5.13309020 E+4
034048,000242:
034049,000243: 31,2363 04143 /AF/CNST DEC .13107
034050,000244:
034051,000245: 31,2364 17777 OCT17777 OCT 17777
034052,000246: 31,2365 35074 4FMAXNOM DEC 14908 B-14 # EQUIVALENT TO 10,500 LBS.
034053,000247: # * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
End of include-file THROTTLE_CONTROL_ROUTINES.agc. Parent file is MAIN.agc