Source Code
![]() |
These source-code files were obtained by digitally photographing the
Colossus 237 program listing from the private collection of original
AGC developer Fred Martin, and then modifying pre-existing Colossus 249
(Apollo 9) source files to incorporate changes. Note that the page images
presented online are of reduced quality, and that additional images
are available. Report any conversion errors or legibility
problems in page images to info@sandroid.org.
Notations on the program listing read, in part:GAP: ASSEMBLE REVISION 237 OF AGC PROGRAM COLOSSUS BY NASA 2021111-031 1:17 AUG. 24, 1968 |
051072,000002: # Copyright: Public domain.
051073,000003: # Filename: PLANETARY_INERTIAL_ORIENTATION.agc
051074,000004: # Purpose: Part of the source code for Colossus build 237.
051075,000005: # This is for the Command Module's (CM) Apollo Guidance
051076,000006: # Computer (AGC), we believe for Apollo 8.
051077,000007: # Assembler: yaYUL
051078,000008: # Contact: Jim Lawton <jim DOT lawton AT gmail DOT com>
051079,000009: # Website: www.ibiblio.org/apollo/index.html
051080,000010: # Page scans: www.ibiblio.org/apollo/ScansForConversion/Colossus237/
051081,000011: # Mod history: 2011-04-13 JL Adapted from corresponding Colossus 249 file.
051082,000012:
051083,000013: # # Page 1210
051084,000014: # ..... RP-TO-R SUBROUTINE .....
051085,000015: # SUBROUTINE TO CONVERT RP (VECTOR IN PLANETARY COORDINATE SYSTEM,EITHER
051086,000016: # EARTH-FIXED OR MOON-FIXED) TO R (SAME VECTOR IN BASIC REF. SYSTEM)
051087,000017:
051088,000018: # R=MT(T)*(RP+LPXRP) MT= M MATRIX TRANSPOSE
051089,000019:
051090,000020: # CALLING SEQUENCE
051091,000021: # L CALL
051092,000022: # L+1 RP-TO-R
051093,000023:
051094,000024: # SUBROUTINES USED
051095,000025: # EARTHMX,MOONMX,EARTHL
051096,000026:
051097,000027: # ITEMS AVAILABLE FROM LAUNCH DATA
051098,000028: # 504LM= THE LIBRATION VECTOR L OF THE MOON AT TIME TIMSUBL,EXPRESSED
051099,000029: # IN THE MOON-FIXED COORD. SYSTEM RADIANS B0
051100,000030: # ITEMS NECESSARY FOR SUBR. USED (SEE DESCRIPTION OF SUBR.)
051101,000031:
051102,000032: # INPUT
051103,000033: # MPAC= 0 FOR EARTH,NON-ZERO FOR MOON
051104,000034: # 0-5D= RP VECTOR
051105,000035: # 6-7D= TIME
051106,000036:
051107,000037: # OUTPUT
051108,000038: # MPAC= R VECTOR METERS B-29 FOR EARTH, B-27 FOR MOON
051109,000039:
051110,000040: 26,2000 SETLOC PLANTIN
051111,000041: 26,2000 BANK
051112,000042:
051113,000043: 26,3341 COUNT* $$/LUROT
051114,000044:
051115,000045: 26,3341 46020 RP-TO-R STQ BHIZ
051116,000046: 26,3342 00050 RPREXIT
051117,000047: 26,3343 55356 RPTORA
051118,000048: 26,3344 77624 CALL # COMPUTE M MATRIX FOR MOON
051119,000049: 26,3345 55416 MOONMX # LP=LM FOR MOON RADIANS B0
051120,000050: 26,3346 77775 VLOAD
051121,000051: 26,3347 02012 504LM
051122,000052: 26,3350 53235 RPTORB VXV VAD
051123,000053: 26,3351 00001 504RPR
051124,000054: 26,3352 00001 504RPR
051125,000055: 26,3353 52105 VXM GOTO
051126,000056: 26,3354 00025 MMATRIX # MPAC=R=MT(T)*(RP+LPXRP)
051127,000057: 26,3355 55404 RPRPXXXX # RESET PUSHLOC TO 0 BEFORE EXITING
051128,000058: 26,3356 77624 RPTORA CALL # EARTH COMPUTATIONS
051129,000059: 26,3357 55570 EARTHMX # M MATRIX B-1
051130,000060: 26,3360 77624 CALL
051131,000061: 26,3361 55622 EARTHL # L VECTOR RADIANS B0
051132,000062: 26,3362 76521 MXV VSL1 # LP=M(T)*L RAD B-0
051133,000063: 26,3363 00025 MMATRIX
051134,000064: # # Page 1211
051135,000065: 26,3364 77650 GOTO
051136,000066: 26,3365 55350 RPTORB
051137,000067:
051138,000068: # # Page 1212
051139,000069: # ..... R-TO-RP SUBROUTINE .....
051140,000070: # SUBROUTINE TO CONVERT R (VECTOR IN REFERENCE COORD. SYSTEM) TO RP
051141,000071: # (VECTOR IN PLANETARY COORD SYSTEM) EITHER EARTH-FIXED OR MOON-FIXED
051142,000072:
051143,000073: # RP=M(T)*(R-LXR)
051144,000074:
051145,000075: # CALLING SEQUENCE
051146,000076: # L CALL
051147,000077: # L+1 R-TO-RP
051148,000078:
051149,000079: # SUBROUTINES USED
051150,000080: # EARTHMX,MOONMX,EARTHL
051151,000081:
051152,000082: # INPUT
051153,000083: # MPAC= 0 FOR EARTH,NON-ZERO FOR MOON
051154,000084: # 0-5D= R VECTOR
051155,000085: # 6-7D= TIME
051156,000086:
051157,000087: # ITEMS AVAILABLE FROM LAUNCH DATA
051158,000088: # 504LM= THE LIBRATION VECTOR L OF THE MOON AT TIME TIMSUBL,EXPRESSED
051159,000089: # IN THE MOON-FIXED COORD. SYSTEM RADIANS B0
051160,000090: # ITEMS NECESSARY FOR SUBROUTINES USED (SEE DESCRIPTION OF SUBR.)
051161,000091:
051162,000092: # OUTPUT
051163,000093: # MPAC=RP VECTOR METERS B-29 FOR EARTH, B-27 FOR MOON
051164,000094:
051165,000095: 26,3366 46020 R-TO-RP STQ BHIZ
051166,000096: 26,3367 00050 RPREXIT
051167,000097: 26,3370 55410 RTORPA
051168,000098: 26,3371 77624 CALL
051169,000099: 26,3372 55416 MOONMX
051170,000100: 26,3373 61375 VLOAD VXM
051171,000101: 26,3374 02012 504LM # LP=LM
051172,000102: 26,3375 00025 MMATRIX
051173,000103: 26,3376 77772 VSL1 # L=MT(T)*LP RADIANS B0
051174,000104: 26,3377 51235 RTORPB VXV BVSU
051175,000105: 26,3400 00001 504RPR
051176,000106: 26,3401 00001 504RPR
051177,000107: 26,3402 77721 MXV # M(T)*(R-LXR) B-2
051178,000108: 26,3403 00025 MMATRIX
051179,000109: 26,3404 40372 RPRPXXXX VSL1 SETPD
051180,000110: 26,3405 00001 0D
051181,000111: 26,3406 77650 GOTO
051182,000112: 26,3407 00050 RPREXIT
051183,000113: 26,3410 77624 RTORPA CALL # EARTH COMPUTATIONS
051184,000114: 26,3411 55570 EARTHMX
051185,000115: 26,3412 77624 CALL
051186,000116: 26,3413 55622 EARTHL
051187,000117: 26,3414 77650 GOTO # MPAC=L=(-AX,-AY,0) RAD B-0
051188,000118: 26,3415 55377 RTORPB
051189,000119:
051190,000120: # # Page 1213
051191,000121: # ..... MOONMX SUBROUTINE .....
051192,000122: # SUBROUTINE TO COMPUTE THE TRANSFORMATION MATRIX M FOR THE MOON
051193,000123:
051194,000124: # CALLING SEQUENCE
051195,000125: # L CALL
051196,000126: # L+1 MOONMX
051197,000127:
051198,000128: # SUBROUTINES USED
051199,000129: # NEWANGLE
051200,000130:
051201,000131: # INPUT
051202,000132: # 6-7D= TIME
051203,000133: # ITEMS AVAILABLE FROM LAUNCH DATA
051204,000134: # BSUBO,BDOT
051205,000135: # TIMSUBO,NODIO,NODDOT,FSUBO,FDOT
051206,000136: # COSI= COS(I) B-1
051207,000137: # SINI= SIN(I) B-1
051208,000138: # I IS THE ANGLE BETWEEN THE MEAN LUNAR EQUATORIAL PLANE AND THE
051209,000139: # PLANE OF THE ECLIPTIC (1 DEGREE 32.1 MINUTES)
051210,000140:
051211,000141: # OUTPUT
051212,000142: # MMATRIX= 3X3 M MATRIX B-1 (STORED IN VAC AREA)
051213,000143:
051214,000144: 26,3416 40220 MOONMX STQ SETPD
051215,000145: 26,3417 00051 EARTHMXX
051216,000146: 26,3420 00011 8D
051217,000147: 26,3421 77770 AXT,1 # B REQUIRES SL 0, SL 5 IN NEWANGLE
051218,000148: 26,3422 00005 5
051219,000149: 26,3423 65345 DLOAD PDDL # PD 10D 8-9D=BSUBO
051220,000150: 26,3424 15652 BSUBO # 10-11D=BDOT
051221,000151: 26,3425 15644 BDOT
051222,000152: 26,3426 45006 PUSH CALL # PD 12D
051223,000153: 26,3427 55543 NEWANGLE # EXIT WITH PD 8D AND MPAC= B REVS B0
051224,000154: 26,3430 71406 PUSH COS # PD 10D
051225,000155: 26,3431 14041 STODL COB # PD 8D COS(B) B-1
051226,000156: 26,3432 77756 SIN # SIN(B) B-1
051227,000157: 26,3433 14043 STODL SOB # SETUP INPUT FOR NEWANGLE
051228,000158: 26,3434 15650 FSUBO # 8-9D=FSUBO
051229,000159: 26,3435 41525 PDDL PUSH # PD 10D THEN 12D 10-11D=FDOT
051230,000160: 26,3436 15642 FDOT
051231,000161: 26,3437 45170 AXT,1 CALL # F REQUIRES SL 1, SL 6 IN NEWANGLE
051232,000162: 26,3440 00004 4
051233,000163: 26,3441 55543 NEWANGLE # EXIT WITH PD 8D AND MPAC= F REVS B0
051234,000164: 26,3442 14027 STODL AVECTR +2 # SAVE F TEMP
051235,000165: 26,3443 15646 NODIO # 8-9D=NODIO
051236,000166: 26,3444 41525 PDDL PUSH # PD 10D THEN 12D 10-11D=NODDOT
051237,000167: 26,3445 15640 NODDOT # MPAC=T
051238,000168: 26,3446 45170 AXT,1 CALL # NODE REQUIRES SL 0, SL 5 IN NEWANGLE
051239,000169: 26,3447 00005 5
051240,000170: 26,3450 55543 NEWANGLE # EXIT WITH PD 8D AND MPAC= NODI REVS B0
051241,000171: # # Page 1214
051242,000172: 26,3451 71406 PUSH COS # PD 10D 8-9D= NODI REVS B0
051243,000173: 26,3452 77606 PUSH # PD 12D 10-11D= COS(NODI) B-1
051244,000174: 26,3453 00025 STORE AVECTR
051245,000175: 26,3454 76405 DMP SL1R
051246,000176: 26,3455 00041 COB # COS(NODI) B-1
051247,000177: 26,3456 14035 STODL BVECTR +2 # PD 10D 20-25D=AVECTR= COB*SIN(NODI)
051248,000178: 26,3457 76405 DMP SL1R # SOB*SIN(NODI)
051249,000179: 26,3460 00043 SOB
051250,000180: 26,3461 14037 STODL BVECTR +4 # PD 8D
051251,000181: 26,3462 41556 SIN PUSH # -SIN(NODI) B-1
051252,000182: 26,3463 77676 DCOMP # 26-31D=BVECTR= COB*COS(NODI)
051253,000183: 26,3464 14033 STODL BVECTR # PD 8D SOB*COS(NODI)
051254,000184: 26,3465 00027 AVECTR +2 # MOVE F FROM TEMP LOC. TO 504F
051255,000185: 26,3466 14007 STODL 504F
051256,000186: 26,3467 76405 DMP SL1R
051257,000187: 26,3470 00041 COB
051258,000188: 26,3471 14027 STODL AVECTR +2
051259,000189: 26,3472 00011 SINNODI # 8-9D=SIN(NODI) B-1
051260,000190: 26,3473 76405 DMP SL1R
051261,000191: 26,3474 00043 SOB
051262,000192: 26,3475 14031 STODL AVECTR +4 # 0
051263,000193: 26,3476 15332 HI6ZEROS # 8-13D= CVECTR= -SOB B-1
051264,000194: 26,3477 57525 PDDL DCOMP # PD 10D COB
051265,000195: 26,3500 00043 SOB
051266,000196: 26,3501 63325 PDDL PDVL # PD 12D THEN PD 14D
051267,000197: 26,3502 00041 COB
051268,000198: 26,3503 00033 BVECTR
051269,000199: 26,3504 63361 VXSC PDVL # PD 20D BVECTR*SINI B-2
051270,000200: 26,3505 15636 SINI
051271,000201: 26,3506 00011 CVECTR
051272,000202: 26,3507 53361 VXSC VAD # PD 14D CVECTR*COSI B-2
051273,000203: 26,3510 15634 COSI
051274,000204: 26,3511 77772 VSL1
051275,000205: 26,3512 24041 STOVL MMATRIX +12D # PD 8D M2=BVECTR*SINI+CVECTR*COSI B-1
051276,000206: 26,3513 63361 VXSC PDVL # PD 14D
051277,000207: 26,3514 15636 SINI # CVECTR*SINI B-2
051278,000208: 26,3515 00033 BVECTR
051279,000209: 26,3516 52361 VXSC VSU # PD 8D BVECTR*COSI B-2
051280,000210: 26,3517 15634 COSI
051281,000211: 26,3520 65372 VSL1 PDDL # PD 14D
051282,000212: 26,3521 00007 504F # 8-13D=DVECTR=BVECTR*COSI-CVECTR*SINI B-1
051283,000213: 26,3522 74346 COS VXSC
051284,000214: 26,3523 00011 DVECTR
051285,000215: 26,3524 73525 PDDL SIN # PD 20D 14-19D= DVECTR*COSF B-2
051286,000216: 26,3525 00007 504F
051287,000217: 26,3526 52361 VXSC VSU # PD 14D AVECTR*SINF B-2
051288,000218: 26,3527 00025 AVECTR
051289,000219: 26,3530 77772 VSL1
051290,000220: 26,3531 14033 STODL MMATRIX +6 # M1= AVECTR*SINF-DVECTR*COSF B-1
051291,000221: 26,3532 00007 504F
051292,000222: # # Page 1215
051293,000223: 26,3533 74356 SIN VXSC # PD 8D
051294,000224: 26,3534 71525 PDDL COS # PD 14D 8-13D=DVECTR*SINF B-2
051295,000225: 26,3535 00007 504F
051296,000226: 26,3536 53361 VXSC VAD # PD 8D AVECTR*COSF B-2
051297,000227: 26,3537 00025 AVECTR
051298,000228: 26,3540 57572 VSL1 VCOMP
051299,000229: 26,3541 34025 STCALL MMATRIX # M0= -(AVECTR*COSF+DVECTR*SINF) B-1
051300,000230: 26,3542 00051 EARTHMXX
051301,000231: # COMPUTE X=X0+(XDOT)(T+T0)
051302,000232: # 8-9D= X0 (REVS B-0),PUSHLOC SET AT 12D
051303,000233: # 10-11D=XDOT (REVS/CSEC) SCALED B+23 FOR WEARTH,B+28 FOR NODDOT AND BDOT
051304,000234: # AND B+27 FOR FDOT
051305,000235: # X1=DIFFERENCE IN 23 AND SCALING OF XDOT,=0 FOR WEARTH,5 FOR NDDOT AND
051306,000236: # BDOT AND 4 FOR FDOT
051307,000237: # 6-7D=T (CSEC B-28), TIMSUBO= (CSEC B-42 TRIPLE PREC.)
051308,000238:
051309,000239: 26,3543 54345 NEWANGLE DLOAD SR # ENTER PD 12D
051310,000240: 26,3544 00007 6D
051311,000241: 26,3545 20617 14D
051312,000242: 26,3546 72371 TAD TLOAD # CHANGE MODE TO TP
051313,000243: 26,3547 01707 TIMSUBO
051314,000244: 26,3550 00155 MPAC
051315,000245: 26,3551 14017 STODL TIMSUBM # T+T0 CSEC B-42
051316,000246: 26,3552 00020 TIMSUBM +1
051317,000247: 26,3553 77605 DMP # PD 10D MULT BY XDOT IN 10-11D
051318,000248: 26,3554 43257 SL* DAD # PD 8D ADD X0 IN 8-9D AFTER SHIFTING
051319,000249: 26,3555 20206 5,1 # SUCH THAT SCALING IS B-0
051320,000250: 26,3556 67206 PUSH SLOAD # PD 10D SAVE PARTIAL (X0+XDOT*T) IN 8-9D
051321,000251: 26,3557 00017 TIMSUBM
051322,000252: 26,3560 41261 SL DMP
051323,000253: 26,3561 20212 9D
051324,000254: 26,3562 00013 10D # XDOT
051325,000255: 26,3563 43257 SL* DAD # PD 8D SHIFT SUCH THAT THIS PART OF X
051326,000256: 26,3564 20213 10D,1 # IS SCALED REVS/CSEC B-0
051327,000257: 26,3565 77600 BOV # TURN OFF OVERFLOW IF SET BY SHIFT
051328,000258: 26,3566 55567 +1 # INSTRUCTION BEFORE EXITING
051329,000259: 26,3567 77616 RVQ # MPAC=X= X0+(XDOT)(T+T0) REVS B0
051330,000260:
051331,000261: # # Page 1216
051332,000262: # ..... EARTHMX SUBROUTINE .....
051333,000263: # SUBROUTINE TO COMPUTE THE TRANSFORMATION MATRIX M FOR THE EARTH
051334,000264:
051335,000265: # CALLING SEQUENCE
051336,000266: # L CALL
051337,000267: # L+1 EARTHMX
051338,000268:
051339,000269: # SUBROUTINE USED
051340,000270: # NEWANGLE
051341,000271:
051342,000272: # INPUT
051343,000273: # INPUT AVAILABLE FROM LAUNCH DATA AZO REVS B-0
051344,000274: # TEPHEM CSEC B-42
051345,000275: # 6-7D= TIME CSEC B-28
051346,000276:
051347,000277: # OUTPUT
051348,000278: # MMATRIX= 3X3 M MATRIX B-1 (STORED IN VAC AREA)
051349,000279:
051350,000280: 26,3570 40220 EARTHMX STQ SETPD # SET 8-9D=AZO
051351,000281: 26,3571 00051 EARTHMXX
051352,000282: 26,3572 00011 8D # 10-11D=WEARTH
051353,000283: 26,3573 77770 AXT,1 # FOR SL 5, AND SL 10 IN NEWANGLE
051354,000284: 26,3574 00000 0
051355,000285: 26,3575 65345 DLOAD PDDL # LEAVING PD SET AT 12D FOR NEWANGLE
051356,000286: 26,3576 01712 AZO
051357,000287: 26,3577 15654 WEARTH
051358,000288: 26,3600 45006 PUSH CALL
051359,000289: 26,3601 55543 NEWANGLE
051360,000290: 26,3602 41401 SETPD PUSH # 18-19D=504AZ
051361,000291: 26,3603 00023 18D # COS(AZ) SIN(AZ) 0
051362,000292: 26,3604 65346 COS PDDL # 20-37D= MMATRIX= -SIN(AZ) COS(AZ) 0 B-1
051363,000293: 26,3605 00023 504AZ # 0 0 1
051364,000294: 26,3606 65356 SIN PDDL
051365,000295: 26,3607 15332 HI6ZEROS
051366,000296: 26,3610 73525 PDDL SIN
051367,000297: 26,3611 00023 504AZ
051368,000298: 26,3612 65276 DCOMP PDDL
051369,000299: 26,3613 00023 504AZ
051370,000300: 26,3614 63346 COS PDVL
051371,000301: 26,3615 15332 HI6ZEROS
051372,000302: 26,3616 41525 PDDL PUSH
051373,000303: 26,3617 15330 HIDPHALF
051374,000304: 26,3620 77650 GOTO
051375,000305: 26,3621 00051 EARTHMXX
051376,000306:
051377,000307: # # Page 1217
051378,000308: # ..... EARTHL SUBROUTINE .....
051379,000309: # SUBROUTINE TO COMPUTE L VECTOR FOR EARTH
051380,000310:
051381,000311: # CALLING SEQUENCE
051382,000312: # L CALL
051383,000313: # L+1 EARTHL
051384,000314:
051385,000315: # INPUT
051386,000316: # AXO,AYO SET AT LAUNCH TIME WITH AYO IMMEDIATELY FOLLOWING AXO IN CORE
051387,000317:
051388,000318: # OUTPUT
051389,000319: # -AX
051390,000320: # MPAC= -AY RADIANS B-0
051391,000321: # 0
051392,000322:
051393,000323: 26,3622 57545 EARTHL DLOAD DCOMP
051394,000324: 26,3623 01716 AXO
051395,000325: 26,3624 14017 STODL 504LPL
051396,000326: 26,3625 01714 -AYO
051397,000327: 26,3626 14021 STODL 504LPL +2
051398,000328: 26,3627 15332 HI6ZEROS
051399,000329: 26,3630 24023 STOVL 504LPL +4
051400,000330: 26,3631 00017 504LPL
051401,000331: 26,3632 77616 RVQ
051402,000332:
051403,000333: # # Page 1218
051404,000334: # CONSTANTS AND ERASABLE ASSIGNMENTS
051405,000335: 26,3633 04,3450 1B1 = DP1/2 # 1 SCALED B-1
051406,000336: 26,3633 17775 01734 COSI 2DEC .99964115 B-1 # COS(1 DEG 32.1 MIN) B-1
051407,000337: 26,3635 00333 16153 SINI 2DEC .02678760 B-1 # SIN(1 DEG 32.1 MIN) B-1
051408,000338: 26,3637 0000050 RPREXIT = S1 # R-TO-RP AND RP-TO-R SUBR EXIT
051409,000339: 26,3637 0000051 EARTHMXX = S2 # EARTHMX,MOONMX SUBR. EXITS
051410,000340: 26,3637 504RPR = 0D # 6 REGS R OR RP VECTOR
051411,000341: 26,3637 SINNODI = 8D # 2 SIN(NODI)
051412,000342: 26,3637 DVECTR = 8D # 6 D VECTOR MOON
051413,000343: 26,3637 CVECTR = 8D # 6 C VECTR MOON
051414,000344: 26,3637 504AZ = 18D # 2 AZ
051415,000345: 26,3637 TIMSUBM = 14D # 3 TIME SUB M (MOON) T+T0 IN GETAZ
051416,000346: 26,3637 504LPL = 14D # 6 L OR LP VECTOR
051417,000347: 26,3637 AVECTR = 20D # 6 A VECTOR (MOON)
051418,000348: 26,3637 BVECTR = 26D # 6 B VECTOR (MOON)
051419,000349: 26,3637 MMATRIX = 20D # 18 M MATRIX
051420,000350: 26,3637 COB = 32D # 2 COS(B) B-1
051421,000351: 26,3637 SOB = 34D # 2 SIN(B) B-1
051422,000352: 26,3637 504F = 6D # 2 F(MOON)
051423,000353: 26,3637 77665 42175 NODDOT 2DEC -.457335143 E-2 # REVS/CSEC B+28=-1.07047016 E-6 RAD/SEC
051424,000354: 26,3641 22211 00265 FDOT 2DEC .570862491 # REVS/CSEC B+27= 2.67240019 E-6 RAD/SEC
051425,000355: 26,3643 77777 77767 BDOT 2DEC -3.07500412 E-8 # REVS/CSEC B+28=-7.19756666 E-14 RAD/SEC
051426,000356: 26,3645 41215 66331 NODIO 2DEC -.960101269 # REVS B-0 = -6.03249419 RAD
051427,000357: 26,3647 15237 26751 FSUBO 2DEC .415998375 # REVS B-0 = 2.61379488 RAD
051428,000358: 26,3651 02052 35713 BSUBO 2DEC .0651205006 # REVS B=0 = 0.409164173 RAD
051429,000359: 26,3653 37116 32630 WEARTH 2DEC .973561855 # REVS/CSEC B+23=7.29211515 E-5 RAD/SEC
End of include-file PLANETARY_INERTIAL_ORIENTATION.agc. Parent file is MAIN.agc