Source Code

This source code is very close to the Apollo Guidance Computer software for the Apollo 13 Lunar module. This revision of the Luminary 131 program is from December of 1969, whereas there was a later revision in January of 1970, and still another revision in February, which is the code that flew on the mission. As far as this transcription is concerned, it was originally from a copy made in 1991 of a printout from the collection of AGC developer Don Eyles for collector David Craig. It was subsequently scanned by Gary Neff, reprocessed for online presentation at the now-discontinued History of Recent Science and Technology (HRST) website of MIT's Dibner Institute (the full-quality scans being discarded in the process), and finally transcribed by Ron Burkey for the Virtual AGC Project. Although a high-quality replacement scan for a completely illegible page was later provided by Gary Neff, the reduced legibility of the reprocessed HRST posting nevertheless caused many errors to be introduced into the transcription. Accordingly, a second scan of the same physical printout was made in 2017 for the Virtual AGC Project's collection at the Internet Archive, and used to correct the transcription errors. All of the scanned materials mentioned, as well as other Luminary 131 related material, are available online. Don Eyles apprently made additional hand-written notes in printout between 1991 and 2017, so the two scans are not identical in that respect. The page-headings in the printout read, in part:
	GAP:  ASSEMBLE REVISION 131 OF AGC PROGRAM LUMINARY BY NASA 2021112-091
	17:53 DEC. 19, 1969
Note that the date is the date the printout was made, not the date on which the program revision was released, although these happen to be very close together.

038242,000002:                                                                                                  ## Copyright:   Public domain.
038243,000003:                                                                                                  ## Filename:    LANDING_ANALOG_DISPLAYS.agc
038244,000004:                                                                                                  ## Purpose:     A section of Luminary 1C, revision 131.
038245,000005:                                                                                                  ##              It is part of the source code for the Lunar Module's (LM)
038246,000006:                                                                                                  ##              Apollo Guidance Computer (AGC) for Apollo 13.
038247,000007:                                                                                                  ##              This file is intended to be a faithful transcription, except
038248,000008:                                                                                                  ##              that the code format has been changed to conform to the
038249,000009:                                                                                                  ##              requirements of the yaYUL assembler rather than the
038250,000010:                                                                                                  ##              original YUL assembler.
038251,000011:                                                                                                  ## Reference:   pp. 891-901
038252,000012:                                                                                                  ## Contact:     Ron Burkey <info@sandroid.org>.
038253,000013:                                                                                                  ## Website:     www.ibiblio.org/apollo/index.html
038254,000014:                                                                                                  ## Mod history: 05/28/03 RSB.   Began transcribing.
038255,000015:                                                                                                  ##              05/14/05 RSB    Corrected website reference above.
038256,000016:                                                                                                  ##              2017-01-06 RSB  Page numbers now agree with those on the
038257,000017:                                                                                                  ##                              original harcopy, as opposed to the PDF page
038258,000018:                                                                                                  ##                              numbers in 1701.pdf.
038259,000019:                                                                                                  ##              2017-02-26 RSB  Proofed comment text using octopus/ProoferComments.
038260,000020:                                                                                                  ##              2017-03-01 RSB  Fixed lingering typos.
038261,000021: 

Page 891

038263,000023: 21,2145                                           BANK     21                                    
038264,000024: 21,2000                                           SETLOC   R10                                   
038265,000025: 21,2000                                           BANK                                           
038266,000026: 
038267,000027: 21,2145  E7,1536                                  EBANK=   UNIT/R/                               
038268,000028: 21,2145                                           COUNT*   $$/R10                                
038269,000029: 
038270,000030: 21,2145           23714        LANDISP            LXCH     PIPCTR1                               #  UPDATE TBASE2 AND PIPCTR SIMULTANEOUSLY.
038271,000031: 21,2146           40025                           CS       TIME1                                 
038272,000032: 21,2147           53055                           DXCH     TBASE2                                
038273,000033: 
038274,000034: 21,2150           40103                           CS       FLAGWRD7                              #  IS LANDING ANALOG DISPLAYS FLAG SET?
038275,000035: 21,2151           74741                           MASK     SWANDBIT                              
038276,000036: 21,2152           10000                           CCS      A                                     
038277,000037: 21,2153           13052                           TCF      DISPRSET                              #  NO.
038278,000038: 21,2154           31300                           CA       IMODES33                              #  BIT 7 = 0 (DO ALTRATE), =1 (DO ALT.)
038279,000039: 21,2155           74745                           MASK     BIT7                                  
038280,000040: 21,2156           10000                           CCS      A                                     
038281,000041: 21,2157           12231                           TCF      ALTOUT                                
038282,000042: 21,2160           02315        ALTROUT            TC       DISINDAT                              #  CHECK MODE SELECT SWITCH AND DIDFLG.
038283,000043: 21,2161           41300                           CS       IMODES33                              
038284,000044: 21,2162           74745                           MASK     BIT7                                  
038285,000045: 21,2163           27300                           ADS      IMODES33                              #  ALTERNATE ALTITUDE RATE WITH ALTITUDE.
038286,000046: 21,2164           34752                           CAF      BIT2                                  #  RATE COMMAND IS EXECUTED BEFORE RANGE.
038287,000047: 21,2165           00006                           EXTEND                                         
038288,000048: 21,2166           05014                           WOR      CHAN14                                #  ALTRATE (BIT2 = 1), ALTITUDE (BIT2 = 0).
038289,000049: 21,2167           31743        ARCOMP             CA       RUNIT                                 #  COMPUTE ALTRATE = RUNIT.VVECT M/CS *2(-6).
038290,000050: 21,2170           00006                           EXTEND                                         
038291,000051: 21,2171           71706                           MP       VVECT                                 #  MULTIPLY X-COMPONENTS.
038292,000052: 21,2172           56070                           XCH      RUPTREG1                              #  SAVE SINGLE PRECISION RESULT M/CS*2(-6).
038293,000053: 21,2173           31744                           CA       RUNIT      +1                         #  MULTIPLY Y-COMPONENTS.
038294,000054: 21,2174           00006                           EXTEND                                         
038295,000055: 21,2175           71707                           MP       VVECT      +1                         
038296,000056: 21,2176           26070                           ADS      RUPTREG1                              #  ACCUMULATE PARTIAL PRODUCTS.
038297,000057: 21,2177           31745                           CA       RUNIT      +2                         #  MULTIPLY Z-COMPONENTS.
038298,000058: 21,2200           00006                           EXTEND                                         
038299,000059: 21,2201           71710                           MP       VVECT      +2                         
038300,000060: 21,2202           26070                           ADS      RUPTREG1                              #  ALTITUDE RATE IN M/CS *2(-6).
038301,000061: 21,2203           32000                           CA       ARCONV                                #  CONVERT ALTRATE TO BIT UNITS (.5FPS/BIT)
038302,000062: 21,2204           00006                           EXTEND                                         
038303,000063: 21,2205           70070                           MP       RUPTREG1                              
038304,000064: 21,2206           20001                           DDOUBL                                         
038305,000065: 21,2207           20001                           DDOUBL                                         
038306,000066: 21,2210           56070                           XCH      RUPTREG1                              #  ALTITUDE RATE IN BIT UNITS*2(-14).
038307,000067: 21,2211           31716                           CA       DALTRATE                              #  ALTITUDE RATE COMPENSATION FACTOR.
038308,000068: 21,2212           00006                           EXTEND                                         
038309,000069: 21,2213           71715                           MP       DT                                    
038310,000070: 21,2214           60070                           AD       RUPTREG1                              
038311,000071: 21,2215           55711                           TS       ALTRATE                               #  ALTITUDE RATE IN BIT UNITS*2(-14).
038312,000072: 21,2216           41711                           CS       ALTRATE                               

Page 892

038314,000074: 21,2217           00006                           EXTEND                                         #  CHECK POLARITY OF ALTITUDE RATE.
038315,000075: 21,2220           62222                           BZMF     +2                                    
038316,000076: 21,2221           12224                           TCF      DATAOUT                               #  NEGATIVE - SEND POS. PULSES TO ALTM REG.
038317,000077: 21,2222           31711                           CA       ALTRATE                               #  POSITIVE OR ZERO - SET SIGN BIT = 1 AND
038318,000078: 21,2223           64735                           AD       BIT15                                 #  SEND TO ALTM REGISTER.  *DO NOT SEND +0*
038319,000079: 21,2224           54060        DATAOUT            TS       ALTM                                  #  ACTIVATE THE LANDING ANALOG DISPLAYS - -
038320,000080: 21,2225           34751                           CAF      BIT3                                  
038321,000081: 21,2226           00006                           EXTEND                                         
038322,000082: 21,2227           05014                           WOR      CHAN14                                #  BIT3 DRIVES THE ALT/ALTRATE METER.
038323,000083: 21,2230           15261                           TCF      TASKOVER                              #  EXIT
038324,000084: 
038325,000085: 21,2231           02315        ALTOUT             TC       DISINDAT                              #  CHECK MODE SELECT SWITCH AND DIDFLG.
038326,000086: 21,2232           44745                           CS       BIT7                                  
038327,000087: 21,2233           71300                           MASK     IMODES33                              
038328,000088: 21,2234           55300                           TS       IMODES33                              #  ALTERNATE ALTITUDE RATE WITH ALTITUDE.
038329,000089: 21,2235           44752                           CS       BIT2                                  
038330,000090: 21,2236           00006                           EXTEND                                         
038331,000091: 21,2237           03014                           WAND     CHAN14                                
038332,000092: 21,2240           11741                           CCS      ALTBITS                               #  = -1 IF OLD ALT. DATA TO BE EXTRAPOLATED.
038333,000093: 21,2241           12245                           TCF      +4                                    
038334,000094: 21,2242           12245                           TCF      +3                                    
038335,000095: 21,2243           12263                           TCF      OLDDATA                               
038336,000096: 21,2244           55741                           TS       ALTBITS                               #  SET ALTBITS FROM -0 TO +0.
038337,000097: 21,2245           44753                           CS       ONE                                   
038338,000098: 21,2246           53742                           DXCH     ALTBITS                               #  SET ALTBITS = -1 FOR SWITCH USE NEXT PASS.
038339,000099: 21,2247           53713                           DXCH     ALTSAVE                               
038340,000100: 21,2250           34742                           CA       BIT10                                 #  NEW ALTITUDE EXTRAPOLATION WITH ALTRATE.
038341,000101: 21,2251           56002                           XCH      Q                                     
038342,000102: 21,2252           22007                           LXCH     7                                     #  ZL
038343,000103: 21,2253           31715                           CA       DT                                    
038344,000104: 21,2254           00006                           EXTEND                                         
038345,000105: 21,2255           10002                           DV       Q                                     #  RESCALE DT*2(-14) TO *2(-9) TIME IN CS.
038346,000106: 21,2256           00006                           EXTEND                                         
038347,000107: 21,2257           72002                           MP       ARTOA2                                #  .0021322 *2(+8)
038348,000108: 21,2260           12264                           TCF      OLDDATA    +1                         #  RATE APPLIES FOR DT CS.
038349,000109: 
038350,000110: 21,2261           53713        ZDATA2             DXCH     ALTSAVE                               
038351,000111: 21,2262           12304                           TCF      NEWDATA                               
038352,000112: 21,2263           32001        OLDDATA            CA       ARTOA                                 #  RATE APPLIES FOR .5 SEC. (4X/SEC. CYCLE)
038353,000113: 21,2264           00006                           EXTEND                                         
038354,000114: 21,2265           71711                           MP       ALTRATE                               #  EXTRAPOLATE WITH ALTITUDE RATE.
038355,000115: 21,2266           20001                           DDOUBL                                         
038356,000116: 21,2267           61713                           AD       ALTSAVE    +1                         
038357,000117: 21,2270           55713                           TS       ALTSAVE    +1                         
038358,000118: 21,2271           34755                           CAF      ZERO                                  
038359,000119: 21,2272           27712                           ADS      ALTSAVE                               
038360,000120: 21,2273           34733                           CAF      POSMAX                                #  FORCE SIGN AGREEMENT ASSUMING A
038361,000121: 21,2274           64753                           AD       ONE                                   #  NON-NEGATIVE ALTSAVE.
038362,000122: 21,2275           61713                           AD       ALTSAVE    +1                         #  IF ALTSAVE IS NEGATIVE, ZERO ALTSAVE
038363,000123: 21,2276           55713                           TS       ALTSAVE    +1                         #  AND ALTSAVE +1 AT ZERODATA.

Page 893

038365,000125: 21,2277           34755                           CAF      ZERO                                  
038366,000126: 21,2300           64733                           AD       POSMAX                                
038367,000127: 21,2301           61712                           AD       ALTSAVE                               
038368,000128: 21,2302           55712                           TS       ALTSAVE                               #  POSSIBLY SKIP TO NEWDATA.
038369,000129: 21,2303           13047                           TCF      ZERODATA                              
038370,000130: 21,2304           11713        NEWDATA            CCS      ALTSAVE    +1                         
038371,000131: 21,2305           12311                           TCF      +4                                    
038372,000132: 21,2306           12311                           TCF      +3                                    
038373,000133: 21,2307           34755                           CAF      ZERO                                  #  SET NEGATIVE ALTSAVE +1 TO +0.
038374,000134: 21,2310           55713                           TS       ALTSAVE    +1                         
038375,000135: 21,2311           11712                           CCS      ALTSAVE                               #  PROVIDE A 15 BIT UNSIGNED OUTPUT.
038376,000136: 21,2312           34735                           CAF      BIT15                                 #  THE HI-ORDER PART IS +1 OR +0.
038377,000137: 21,2313           61713                           AD       ALTSAVE    +1                         
038378,000138: 21,2314           12224                           TCF      DATAOUT                               #  DISPATCH UNSIGNED BITS TO ALTM REG.
038379,000139: 21,2315           00006        DISINDAT           EXTEND                                         
038380,000140: 21,2316           23714                           QXCH     LADQSAVE                              #  SAVE RETURN TO ALTROUT +1 OR ALTOUT +1
038381,000141: 21,2317           34746                           CAF      BIT6                                  
038382,000142: 21,2320           00006                           EXTEND                                         #  WISHETH THE ASTRONAUT THE ANALOG
038383,000143: 21,2321           02030                           RAND     CHAN30                                #  DISPLAYS?  I.E.,
038384,000144: 21,2322           10000                           CCS      A                                     #  IS THE MODE SELECT SWITCH IN PGNCS?
038385,000145: 21,2323           13052                           TCF      DISPRSET                              #  NO.  ASTRONAUT REQUESTS NO INERTIAL DATA
038386,000146: 21,2324           40075                           CS       FLAGWRD1                              #  YES.  CHECK STATUS OF DIDFLAG.
038387,000147: 21,2325           74736                           MASK     DIDFLBIT                              
038388,000148: 21,2326           00006                           EXTEND                                         
038389,000149: 21,2327           12365                           BZF      SPEEDRUN                              #  SET.  PERFORM DATA DISPLAY SEQUENCE.
038390,000150: 21,2330           40075                           CS       FLAGWRD1                              #  RESET.  PERFORM INITIALIZATION FUNCTIONS.
038391,000151: 21,2331           74736                           MASK     DIDFLBIT                              
038392,000152: 21,2332           26075                           ADS      FLAGWRD1                              #  SET DIDFLAG.
038393,000153: 21,2333           44745                           CS       BIT7                                  
038394,000154: 21,2334           71300                           MASK     IMODES33                              #  TO DISPLAY ALTRATE FIRST AND ALT. SECOND
038395,000155: 21,2335           55300                           TS       IMODES33                              
038396,000156: 21,2336           40074                           CS       FLAGWRD0                              #  ARE WE IN DESCENT TRAJECTORY?
038397,000157: 21,2337           74752                           MASK     R10FLBIT                              
038398,000158: 21,2340           00006                           EXTEND                                         
038399,000159: 21,2341           15261                           BZF      TASKOVER                              #  NO
038400,000160: 21,2342           34744                           CAF      BIT8                                  #  YES.
038401,000161: 21,2343           00006                           EXTEND                                         
038402,000162: 21,2344           05012                           WOR      CHAN12                                #  SET DISPLAY INERTIAL DATA OUTBIT.
038403,000163: 21,2345           34755                           CAF      ZERO                                  
038404,000164: 21,2346           55702                           TS       TRAKLATV                              #  LATERAL VELOCITY MONITOR FLAG
038405,000165: 21,2347           55703                           TS       TRAKFWDV                              #  FORWARD VELOCITY MONITOR FLAG
038406,000166: 21,2350           55676                           TS       LATVMETR                              #  LATVEL MONITOR METER
038407,000167: 21,2351           55677                           TS       FORVMETR                              #  FORVEL MONITOR METER
038408,000168: 21,2352           34750                           CAF      BIT4                                  
038409,000169: 21,2353           05173                           TC       TWIDDLE                               
038410,000170: 21,2354           02356                           ADRES    INTLZE                                
038411,000171: 21,2355           15261                           TCF      TASKOVER                              
038412,000172: 21,2356           34752        INTLZE             CAF      BIT2                                  
038413,000173: 21,2357           00006                           EXTEND                                         
038414,000174: 21,2360           05012                           WOR      CHAN12                                #  ENABLE RR ERROR COUNTER.

Page 894

038416,000176: 21,2361           41300                           CS       IMODES33                              
038417,000177: 21,2362           74744                           MASK     BIT8                                  
038418,000178: 21,2363           27300                           ADS      IMODES33                              #  SET INERTIAL DATA FLAG.
038419,000179: 21,2364           15261                           TCF      TASKOVER                              
038420,000180: 
038421,000181: 21,2365           41234        SPEEDRUN           CS       PIPTIME    +1                         #  UPDATE THE VELOCITY VECTOR
038422,000182: 21,2366           60025                           AD       TIME1                                 #  COMPUTE T - TN
038423,000183: 21,2367           64736                           AD       HALF                                  #  CORRECT FOR POSSIBLE OVERFLOW OF TIME1.
038424,000184: 21,2370           64736                           AD       HALF                                  
038425,000185: 21,2371           57715                           XCH      DT                                    #  SAVE FOR LATER USE
038426,000186: 21,2372           34777                           CA       1SEC                                  
038427,000187: 21,2373           54065                           TS       ITEMP5                                #  INITIALIZE FOR DIVISION LATER
038428,000188: 21,2374           00006                           EXTEND                                         
038429,000189: 21,2375           31236                           DCA      GDT/2                                 #  COMPUTE THE X-COMPONENT OF VELOCITY.
038430,000190: 21,2376           20001                           DDOUBL                                         
038431,000191: 21,2377           20001                           DDOUBL                                         
038432,000192: 21,2400           00006                           EXTEND                                         
038433,000193: 21,2401           71715                           MP       DT                                    
038434,000194: 21,2402           00006                           EXTEND                                         
038435,000195: 21,2403           10065                           DV       ITEMP5                                
038436,000196: 21,2404           57706                           XCH      VVECT                                 #  VVECT = G(T-TN) M/CS *2(-5)
038437,000197: 21,2405           00006                           EXTEND                                         
038438,000198: 21,2406           31527                           DCA      V                                     #  M/CS *2(-7)
038439,000199: 21,2407           20001                           DDOUBL                                         #  RESCALE TO 2(-5)
038440,000200: 21,2410           20001                           DDOUBL                                         
038441,000201: 21,2411           27706                           ADS      VVECT                                 #  VVECT = VN + G(T-TN) M/CS *2(-5)
038442,000202: 21,2412           30037                           CA       PIPAX                                 #  DELV CM/SEC *2(-14)
038443,000203: 21,2413           61157                           AD       PIPATMPX                              #  IN CASE PIPAX HAS BEEN ZEROED
038444,000204: 21,2414           00006                           EXTEND                                         
038445,000205: 21,2415           72004                           MP       KPIP1(5)                              #  DELV M/CS *2(-5)
038446,000206: 21,2416           27706                           ADS      VVECT                                 #  VVECT = VN + DELV + GN(T-TN) M/CS *2(-5)
038447,000207: 21,2417           00006                           EXTEND                                         
038448,000208: 21,2420           31240                           DCA      GDT/2      +2                         #  COMPUTE THE Y-COMPONENT OF VELOCITY.
038449,000209: 21,2421           20001                           DDOUBL                                         
038450,000210: 21,2422           20001                           DDOUBL                                         
038451,000211: 21,2423           00006                           EXTEND                                         
038452,000212: 21,2424           71715                           MP       DT                                    
038453,000213: 21,2425           00006                           EXTEND                                         
038454,000214: 21,2426           10065                           DV       ITEMP5                                
038455,000215: 21,2427           57707                           XCH      VVECT      +1                         
038456,000216: 21,2430           00006                           EXTEND                                         
038457,000217: 21,2431           31531                           DCA      V          +2                         
038458,000218: 21,2432           20001                           DDOUBL                                         
038459,000219: 21,2433           20001                           DDOUBL                                         
038460,000220: 21,2434           27707                           ADS      VVECT      +1                         
038461,000221: 21,2435           30040                           CA       PIPAY                                 
038462,000222: 21,2436           61160                           AD       PIPATMPY                              
038463,000223: 21,2437           00006                           EXTEND                                         
038464,000224: 21,2440           72004                           MP       KPIP1(5)                              
038465,000225: 21,2441           27707                           ADS      VVECT      +1                         

Page 895

038467,000227: 21,2442           00006                           EXTEND                                         
038468,000228: 21,2443           31242                           DCA      GDT/2      +4                         #  COMPUTE THE Z-COMPONENT OF VELOCITY.
038469,000229: 21,2444           20001                           DDOUBL                                         
038470,000230: 21,2445           20001                           DDOUBL                                         
038471,000231: 21,2446           00006                           EXTEND                                         
038472,000232: 21,2447           71715                           MP       DT                                    
038473,000233: 21,2450           00006                           EXTEND                                         
038474,000234: 21,2451           10065                           DV       ITEMP5                                
038475,000235: 21,2452           57710                           XCH      VVECT      +2                         
038476,000236: 21,2453           00006                           EXTEND                                         
038477,000237: 21,2454           31533                           DCA      V          +4                         
038478,000238: 21,2455           20001                           DDOUBL                                         
038479,000239: 21,2456           20001                           DDOUBL                                         
038480,000240: 21,2457           27710                           ADS      VVECT      +2                         
038481,000241: 21,2460           30041                           CA       PIPAZ                                 
038482,000242: 21,2461           61161                           AD       PIPATMPZ                              
038483,000243: 21,2462           00006                           EXTEND                                         
038484,000244: 21,2463           72004                           MP       KPIP1(5)                              
038485,000245: 21,2464           27710                           ADS      VVECT      +2                         
038486,000246: 
038487,000247: 21,2465           34751                           CAF      BIT3                                  #  PAUSE 40 MS TO LET OTHER RUPTS IN.
038488,000248: 21,2466           05224                           TC       VARDELAY                              
038489,000249: 
038490,000250: 21,2467           40074                           CS       FLAGWRD0                              #  ARE WE IN DESCENT TRAJECTORY?
038491,000251: 21,2470           74752                           MASK     R10FLBIT                              
038492,000252: 21,2471           10000                           CCS      A                                     
038493,000253: 21,2472           12474                           TCF      +2                                    #  YES.
038494,000254: 21,2473           01714                           TC       LADQSAVE                              #  NO.
038495,000255: 
038496,000256: 21,2474           34752                           CAF      BIT2                                  #  CHECK TO SEE IF RR ERROR COUNTERS
038497,000257: 21,2475           00006                           EXTEND                                         #  ARE ENABLED.
038498,000258: 21,2476           02012                           RAND     CHAN12                                
038499,000259: 21,2477           10000                           CCS      A                                     #  IF NOT.
038500,000260: 21,2500           12502                           TCF      +2                                    
038501,000261: 21,2501           13052                           TCF      DISPRSET                              #  RE-INITIALIZE LANDING ANALOG DISPLAYS
038502,000262: 
038503,000263: 21,2502           31733                           CA       DELVS                                 #  HI X OF VELOCITY CORRECTION TERM.
038504,000264: 21,2503           61706                           AD       VVECT                                 #  HI X OF UPDATED VELOCITY VECTOR.
038505,000265: 21,2504           54061                           TS       ITEMP1                                #  = VX - DVX M/CS *2(-5).
038506,000266: 21,2505           31735                           CA       DELVS      +2                         #     Y
038507,000267: 21,2506           61707                           AD       VVECT      +1                         #     Y
038508,000268: 21,2507           54062                           TS       ITEMP2                                #  = VY - DVY M/CS *2(-5).
038509,000269: 21,2510           31737                           CA       DELVS      +4                         #     Z
038510,000270: 21,2511           61710                           AD       VVECT      +2                         #     Z
038511,000271: 21,2512           54063                           TS       ITEMP3                                #  = VZ - DVZ M/CS *2(-5).
038512,000272: 21,2513           30061                           CA       ITEMP1                                #  COMPUTE VHY, VELOCITY DIRECTED ALONG THE
038513,000273: 21,2514           00006                           EXTEND                                         #  Y-COORDINATE.
038514,000274: 21,2515           71717                           MP       UHYP                                  #  HI X OF CROSS-RANGE HALF-UNIT VECTOR.
038515,000275: 21,2516           56070                           XCH      RUPTREG1                              
038516,000276: 21,2517           30062                           CA       ITEMP2                                

Page 896

038518,000278: 21,2520           00006                           EXTEND                                         
038519,000279: 21,2521           71721                           MP       UHYP       +2                         #  Y
038520,000280: 21,2522           26070                           ADS      RUPTREG1                              #  ACCUMULATE PARTIAL PRODUCTS.
038521,000281: 21,2523           30063                           CA       ITEMP3                                
038522,000282: 21,2524           00006                           EXTEND                                         
038523,000283: 21,2525           71723                           MP       UHYP       +4                         #  Z
038524,000284: 21,2526           26070                           ADS      RUPTREG1                              
038525,000285: 21,2527           30070                           CA       RUPTREG1                              
038526,000286: 21,2530           60000                           DOUBLE                                         
038527,000287: 21,2531           57704                           XCH      VHY                                   #  VHY=VMP.UHYP M/CS*2(-5).
038528,000288: 21,2532           30061                           CA       ITEMP1                                #  NOW COMPUTE VHZ, VELOCITY DIRECTED ALONG
038529,000289: 21,2533           00006                           EXTEND                                         #  THE Z-COORDINATE.
038530,000290: 21,2534           71725                           MP       UHZP                                  #  HI X OF DOWN-RANGE HALF-UNIT VECTOR.
038531,000291: 21,2535           56070                           XCH      RUPTREG1                              
038532,000292: 21,2536           30062                           CA       ITEMP2                                
038533,000293: 21,2537           00006                           EXTEND                                         
038534,000294: 21,2540           71727                           MP       UHZP       +2                         #  Y
038535,000295: 21,2541           26070                           ADS      RUPTREG1                              #  ACCUMULATE PARTIAL PRODUCTS.
038536,000296: 21,2542           30063                           CA       ITEMP3                                
038537,000297: 21,2543           00006                           EXTEND                                         
038538,000298: 21,2544           71731                           MP       UHZP       +4                         #  Z
038539,000299: 21,2545           26070                           ADS      RUPTREG1                              
038540,000300: 21,2546           30070                           CA       RUPTREG1                              
038541,000301: 21,2547           60000                           DOUBLE                                         
038542,000302: 21,2550           57705                           XCH      VHZ                                   #  VHZ = VMP.UHZP M/CS*2(-5).
038543,000303: 21,2551           35015        GET22/32           CAF      EBANK6                                #  GET SIN(AOG),COS(AOG) FROM GPMATRIX.
038544,000304: 21,2552           54003                           TS       EBANK                                 
038545,000305: 21,2553  E6,1417                                  EBANK=   M22                                   
038546,000306: 21,2553           31417                           CA       M22                                   
038547,000307: 21,2554           54063                           TS       ITEMP3                                
038548,000308: 21,2555           31420                           CA       M32                                   
038549,000309: 21,2556           54064                           TS       ITEMP4                                
038550,000310: 21,2557           35016                           CAF      EBANK7                                
038551,000311: 21,2560           54003                           TS       EBANK                                 
038552,000312: 21,2561  E7,1536                                  EBANK=   UNIT/R/                               
038553,000313: 21,2561           30064        LADFWDV            CA       ITEMP4                                #  COMPUTE LATERAL AND FORWARD VELOCITIES.
038554,000314: 21,2562           00006                           EXTEND                                         
038555,000315: 21,2563           71704                           MP       VHY                                   
038556,000316: 21,2564           56070                           XCH      RUPTREG1                              
038557,000317: 21,2565           30063                           CA       ITEMP3                                
038558,000318: 21,2566           00006                           EXTEND                                         
038559,000319: 21,2567           71705                           MP       VHZ                                   
038560,000320: 21,2570           26070                           ADS      RUPTREG1                              #  = VHY(COS)AOG+VHZ(SIN)AOG M/CS *2(-5)
038561,000321: 21,2571           32003                           CA       VELCONV                               #  CONVERT LATERAL VELOCITY TO BIT UNITS.
038562,000322: 21,2572           00006                           EXTEND                                         
038563,000323: 21,2573           70070                           MP       RUPTREG1                              
038564,000324: 21,2574           20001                           DDOUBL                                         
038565,000325: 21,2575           57700                           XCH      LATVEL                                #  LATERAL VELOCITY IN BIT UNITS *2(-14).
038566,000326: 21,2576           30064                           CA       ITEMP4                                #  COMPUTE FORWARD VELOCITY.
038567,000327: 21,2577           00006                           EXTEND                                         

Page 897

038569,000329: 21,2600           71705                           MP       VHZ                                   
038570,000330: 21,2601           56070                           XCH      RUPTREG1                              
038571,000331: 21,2602           30063                           CA       ITEMP3                                
038572,000332: 21,2603           00006                           EXTEND                                         
038573,000333: 21,2604           71704                           MP       VHY                                   
038574,000334: 21,2605           40000                           CS       A                                     
038575,000335: 21,2606           26070                           ADS      RUPTREG1                              #  =VHZ(COS)AOG-VHY(SIN)AOG M/CS *2(-5).
038576,000336: 21,2607           32003                           CA       VELCONV                               #  CONVERT FORWARD VELOCITY TO BIT UNITS.
038577,000337: 21,2610           00006                           EXTEND                                         
038578,000338: 21,2611           70070                           MP       RUPTREG1                              
038579,000339: 21,2612           20001                           DDOUBL                                         
038580,000340: 21,2613           57701                           XCH      FORVEL                                #  FORWARD VELOCITY IN BIT UNITS *2(-14).
038581,000341: 
038582,000342: 21,2614           42005                           CS       MAXVBITS                              #  ACC.=-199.9989 FT./SEC.
038583,000343: 21,2615           54066                           TS       ITEMP6                                #  -547 BIT UNITS (OCTAL) AT 0.5571 FPS/BIT
038584,000344: 
038585,000345: 21,2616           34753                           CAF      ONE                                   #  LOOP TWICE.
038586,000346: 21,2617           54065        VMONITOR           TS       ITEMP5                                #  FORWARD AND LATERAL VELOCITY LANDING
038587,000347: 21,2620           50065                           INDEX    ITEMP5                                #        ANALOG DISPLAYS MONITOR.
038588,000348: 21,2621           11700                           CCS      LATVEL                                
038589,000349: 21,2622           12626                           TCF      +4                                    
038590,000350: 21,2623           12727                           TCF      LVLIMITS                              
038591,000351: 21,2624           12634                           TCF      +8D                                   
038592,000352: 21,2625           12727                           TCF      LVLIMITS                              
038593,000353: 21,2626           50065                           INDEX    ITEMP5                                
038594,000354: 21,2627           41700                           CS       LATVEL                                
038595,000355: 21,2630           62005                           AD       MAXVBITS                              #  +199.9989 FT./SEC.
038596,000356: 21,2631           00006                           EXTEND                                         
038597,000357: 21,2632           62642                           BZMF     CHKLASTY                              
038598,000358: 21,2633           12727                           TCF      LVLIMITS                              
038599,000359: 21,2634           50065                           INDEX    ITEMP5                                
038600,000360: 21,2635           31700                           CA       LATVEL                                
038601,000361: 21,2636           62005                           AD       MAXVBITS                              
038602,000362: 21,2637           00006                           EXTEND                                         
038603,000363: 21,2640           62642                           BZMF     +2                                    
038604,000364: 21,2641           12727                           TCF      LVLIMITS                              
038605,000365: 21,2642           50065        CHKLASTY           INDEX    ITEMP5                                
038606,000366: 21,2643           11676                           CCS      LATVMETR                              
038607,000367: 21,2644           12650                           TCF      +4                                    
038608,000368: 21,2645           12661                           TCF      LASTOK                                
038609,000369: 21,2646           12655                           TCF      +7                                    
038610,000370: 21,2647           12661                           TCF      LASTOK                                
038611,000371: 21,2650           50065                           INDEX    ITEMP5                                
038612,000372: 21,2651           31700                           CA       LATVEL                                
038613,000373: 21,2652           00006                           EXTEND                                         
038614,000374: 21,2653           62700                           BZMF     LASTPOSY   +5                         
038615,000375: 21,2654           12661                           TCF      +5                                    
038616,000376: 21,2655           50065                           INDEX    ITEMP5                                
038617,000377: 21,2656           41700                           CS       LATVEL                                
038618,000378: 21,2657           00006                           EXTEND                                         

Page 898

038620,000380: 21,2660           62715                           BZMF     LASTNEGY   +4                         
038621,000381: 21,2661           50065        LASTOK             INDEX    ITEMP5                                
038622,000382: 21,2662           11702                           CCS      TRAKLATV                              
038623,000383: 21,2663           12673                           TCF      LASTPOSY                              
038624,000384: 21,2664           12666                           TCF      +2                                    
038625,000385: 21,2665           12711                           TCF      LASTNEGY                              
038626,000386: 21,2666           50065                           INDEX    ITEMP5                                
038627,000387: 21,2667           31700                           CA       LATVEL                                
038628,000388: 21,2670           00006                           EXTEND                                         
038629,000389: 21,2671           62717                           BZMF     NEGVMAXY                              
038630,000390: 21,2672           12702                           TCF      POSVMAXY                              
038631,000391: 21,2673           50065        LASTPOSY           INDEX    ITEMP5                                
038632,000392: 21,2674           31700                           CA       LATVEL                                
038633,000393: 21,2675           00006                           EXTEND                                         
038634,000394: 21,2676           62700                           BZMF     +2                                    
038635,000395: 21,2677           12702                           TCF      POSVMAXY                              
038636,000396: 21,2700           42005                           CS       MAXVBITS                              
038637,000397: 21,2701           13023                           TCF      ZEROLSTY                              
038638,000398: 21,2702           50065        POSVMAXY           INDEX    ITEMP5                                
038639,000399: 21,2703           41676                           CS       LATVMETR                              
038640,000400: 21,2704           62005                           AD       MAXVBITS                              
038641,000401: 21,2705           50065                           INDEX    ITEMP5                                
038642,000402: 21,2706           56072                           XCH      RUPTREG3                              
038643,000403: 21,2707           34753                           CAF      ONE                                   
038644,000404: 21,2710           13026                           TCF      ZEROLSTY   +3                         
038645,000405: 21,2711           50065        LASTNEGY           INDEX    ITEMP5                                
038646,000406: 21,2712           31700                           CA       LATVEL                                
038647,000407: 21,2713           00006                           EXTEND                                         
038648,000408: 21,2714           62717                           BZMF     NEGVMAXY                              
038649,000409: 21,2715           32005                           CA       MAXVBITS                              
038650,000410: 21,2716           13023                           TCF      ZEROLSTY                              
038651,000411: 21,2717           50065        NEGVMAXY           INDEX    ITEMP5                                
038652,000412: 21,2720           31676                           CA       LATVMETR                              
038653,000413: 21,2721           62005                           AD       MAXVBITS                              
038654,000414: 21,2722           40000                           COM                                            
038655,000415: 21,2723           50065                           INDEX    ITEMP5                                
038656,000416: 21,2724           56072                           XCH      RUPTREG3                              
038657,000417: 21,2725           44753                           CS       ONE                                   
038658,000418: 21,2726           13026                           TCF      ZEROLSTY   +3                         
038659,000419: 21,2727           50065        LVLIMITS           INDEX    ITEMP5                                
038660,000420: 21,2730           11702                           CCS      TRAKLATV                              
038661,000421: 21,2731           12760                           TCF      LATVPOS                               
038662,000422: 21,2732           12734                           TCF      +2                                    
038663,000423: 21,2733           12765                           TCF      LATVNEG                               
038664,000424: 21,2734           50065                           INDEX    ITEMP5                                
038665,000425: 21,2735           41676                           CS       LATVMETR                              
038666,000426: 21,2736           00006                           EXTEND                                         
038667,000427: 21,2737           62741                           BZMF     +2                                    
038668,000428: 21,2740           12774                           TCF      NEGLMLV                               
038669,000429: 21,2741           50065                           INDEX    ITEMP5                                

Page 899

038671,000431: 21,2742           41700                           CS       LATVEL                                
038672,000432: 21,2743           00006                           EXTEND                                         
038673,000433: 21,2744           63017                           BZMF     LVMINLM                               
038674,000434: 21,2745           60066                           AD       ITEMP6                                
038675,000435: 21,2746           50065                           INDEX    ITEMP5                                
038676,000436: 21,2747           61676                           AD       LATVMETR                              
038677,000437: 21,2750           00006                           EXTEND                                         
038678,000438: 21,2751           63017                           BZMF     LVMINLM                               
038679,000439: 21,2752           50065                           INDEX    ITEMP5                                
038680,000440: 21,2753           61700                           AD       LATVEL                                
038681,000441: 21,2754           00006                           EXTEND                                         
038682,000442: 21,2755           50065                           INDEX    ITEMP5                                
038683,000443: 21,2756           61676                           SU       LATVMETR                              
038684,000444: 21,2757           13023                           TCF      ZEROLSTY                              
038685,000445: 21,2760           50065        LATVPOS            INDEX    ITEMP5                                
038686,000446: 21,2761           41700                           CS       LATVEL                                
038687,000447: 21,2762           00006                           EXTEND                                         
038688,000448: 21,2763           63017                           BZMF     LVMINLM                               
038689,000449: 21,2764           12771                           TCF      +5                                    
038690,000450: 21,2765           50065        LATVNEG            INDEX    ITEMP5                                
038691,000451: 21,2766           31700                           CA       LATVEL                                
038692,000452: 21,2767           00006                           EXTEND                                         
038693,000453: 21,2770           63017                           BZMF     LVMINLM                               
038694,000454: 21,2771           50065                           INDEX    ITEMP5                                
038695,000455: 21,2772           41676                           CS       LATVMETR                              
038696,000456: 21,2773           13023                           TCF      ZEROLSTY                              
038697,000457: 21,2774           50065        NEGLMLV            INDEX    ITEMP5                                
038698,000458: 21,2775           31700                           CA       LATVEL                                
038699,000459: 21,2776           00006                           EXTEND                                         
038700,000460: 21,2777           63017                           BZMF     LVMINLM                               
038701,000461: 21,3000           32005                           CA       MAXVBITS                              
038702,000462: 21,3001           50065                           INDEX    ITEMP5                                
038703,000463: 21,3002           61676                           AD       LATVMETR                              
038704,000464: 21,3003           40000                           COM                                            
038705,000465: 21,3004           50065                           INDEX    ITEMP5                                
038706,000466: 21,3005           61700                           AD       LATVEL                                
038707,000467: 21,3006           00006                           EXTEND                                         
038708,000468: 21,3007           63017                           BZMF     LVMINLM                               
038709,000469: 21,3010           00006                           EXTEND                                         
038710,000470: 21,3011           50065                           INDEX    ITEMP5                                
038711,000471: 21,3012           61700                           SU       LATVEL                                
038712,000472: 21,3013           50065                           INDEX    ITEMP5                                
038713,000473: 21,3014           61676                           AD       LATVMETR                              
038714,000474: 21,3015           40000                           COM                                            
038715,000475: 21,3016           13023                           TCF      ZEROLSTY                              
038716,000476: 21,3017           50065        LVMINLM            INDEX    ITEMP5                                
038717,000477: 21,3020           41676                           CS       LATVMETR                              
038718,000478: 21,3021           50065                           INDEX    ITEMP5                                
038719,000479: 21,3022           61700                           AD       LATVEL                                
038720,000480: 21,3023           50065        ZEROLSTY           INDEX    ITEMP5                                

Page 900

038722,000482: 21,3024           56072                           XCH      RUPTREG3                              
038723,000483: 21,3025           34755                           CAF      ZERO                                  
038724,000484: 21,3026           50065                           INDEX    ITEMP5                                
038725,000485: 21,3027           55702                           TS       TRAKLATV                              
038726,000486: 21,3030           50065                           INDEX    ITEMP5                                
038727,000487: 21,3031           30072                           CA       RUPTREG3                              
038728,000488: 21,3032           64754                           AD       NEG0                                  #  AVOIDS +0 DINC HARDWARE MALFUNCTION
038729,000489: 21,3033           50065                           INDEX    ITEMP5                                
038730,000490: 21,3034           54053                           TS       CDUTCMD                               
038731,000491: 21,3035           50065                           INDEX    ITEMP5                                
038732,000492: 21,3036           30072                           CA       RUPTREG3                              
038733,000493: 21,3037           50065                           INDEX    ITEMP5                                
038734,000494: 21,3040           27676                           ADS      LATVMETR                              
038735,000495: 21,3041           10065                           CCS      ITEMP5                                #  FIRST MONITOR FORWARD THEN LATERAL VEL.
038736,000496: 21,3042           12617                           TCF      VMONITOR                              
038737,000497: 
038738,000498: 21,3043           35020                           CAF      BITSET                                #  DRIVE THE X-POINTER DISPLAY.
038739,000499: 21,3044           00006                           EXTEND                                         
038740,000500: 21,3045           05014                           WOR      CHAN14                                
038741,000501: 21,3046           01714                           TC       LADQSAVE                              #  GO TO ALTROUT +1 OR TO ALTOUT +1
038742,000502: 21,3047           34755        ZERODATA           CAF      ZERO                                  #  ZERO ALTSAVE AND ALTSAVE +1 - - -
038743,000503: 21,3050           54001                           TS       L                                     #        NO NEGATIVE ALTITUDES ALLOWED.
038744,000504: 21,3051           12261                           TCF      ZDATA2                                
038745,000505: 
038746,000506:                                                                                                  #  ************************************************************************
038747,000507: 
038748,000508: 21,3052           40074        DISPRSET           CS       FLAGWRD0                              #  ARE WE IN DESCENT TRAJECTORY?
038749,000509: 21,3053           74752                           MASK     R10FLBIT                              
038750,000510: 21,3054           00006                           EXTEND                                         
038751,000511: 21,3055           13066                           BZF      ABORTON                               #  NO.
038752,000512: 21,3056           34744                           CAF      BIT8                                  #  YES.
038753,000513: 21,3057           71300                           MASK     IMODES33                              #  CHECK IF INERTIAL DATA JUST DISPLAYED.
038754,000514: 21,3060           10000                           CCS      A                                     
038755,000515: 21,3061           34752                           CAF      BIT2                                  #  YES. DISABLE RR ERROR COUNTER
038756,000516: 21,3062           64744                           AD       BIT8                                  #  NO.  REMOVE DISPLAY INERTIAL DATA
038757,000517: 21,3063           40000                           COM                                            
038758,000518: 21,3064           00006                           EXTEND                                         
038759,000519: 21,3065           03012                           WAND     CHAN12                                
038760,000520: 21,3066           43075        ABORTON            CS       BITS8/7                               #  RESET INERTIAL DATA, INTERLEAVE FLAGS.
038761,000521: 21,3067           71300                           MASK     IMODES33                              
038762,000522: 21,3070           55300                           TS       IMODES33                              
038763,000523: 21,3071           44736                           CS       DIDFLBIT                              
038764,000524: 21,3072           70075                           MASK     FLAGWRD1                              
038765,000525: 21,3073           54075                           TS       FLAGWRD1                              #  RESET DIDFLAG.
038766,000526: 21,3074           15261                           TCF      TASKOVER                              
038767,000527: 
038768,000528:                                                                                                  #  ************************************************************************
038769,000529: 
038770,000530: 21,3075           00300        BITS8/7            OCT      00300                                 #  INERTIAL DATA AND INTERLEAVE FLAGS.
038771,000531: 21,3076     5020               BITSET             =        PRIO6                                 
038772,000532: 
038773,000533:                                                                                                  #  ************************************************************************
038774,000534: 

Page 901 There is no source code on the original program listing.

038777,000537: 

End of include-file LANDING_ANALOG_DISPLAYS.agc.  Parent file is MAIN.agc