Assembly listing generated by yaYUL

Source Code

These source-code files are part of a reconstructed copy of Comanche 72/3 (AKA Manche72 revision 3), the final, flown mission release of the Apollo Guidance Computer (AGC) Command Module (CM) software for Apollo 13.

The starting point was the source code of Comanche 72 (itself previously reconstructed). Comanche 72 source code was then modified by incorporating changes known from contemporary documentation to have been made between revisions 72 and 72/3. The resulting code assembles to have identical memory-bank checksums as those specified in NASA drawing 2021153G; this gives reasonably high confidence that the changes that have been made are correct. In places where ambiguity exists, this ambiguity is discussed in "## Reconstruction:" comments.

Since no contemporary listings of Comanche 72/3 are available as source material, all comments and labels are approximate. They have been taken from other AGC programs where possible, or, in some places, written from scratch to match what we believe would have been in the original listing.

016440,000002: 016441,000003: 016442,000004: 016443,000005: 016444,000006: 016445,000007: 016446,000008: 016447,000009: 016448,000010: 016449,000011: 016450,000012: 016451,000013: 016452,000014: 016453,000015: 016454,000016: 016455,000017: 016456,000018: 016457,000019: 34,2002 016458,000020: 27,2000 016459,000021: 27,2000 016460,000022: 016461,000023: 27,2000 016462,000024: 016463,000025: 27,2000 016464,000026: 016465,000027: 016466,000028: 016467,000029: < 016760,000322: 27,2311 016761,000323: 27,2312 016762,000324: 35,2000 016763,000325: 27,2000 016764,000326: 27,2000 016765,000327: ## Copyright: Public domain. ## Filename: R60,R62.agc ## Purpose: A section of Manche72 revision 3. ## It is part of the reconstructed source code for the final, flown ## release of the software for the Command Module's (CM) Apollo ## Guidance Computer (AGC) for Apollo 13. No original listings ## of this program are available; instead, this file was recreated ## from a reconstructed copy of Comanche 072. It has been adapted ## such that the resulting bugger words exactly match those ## specified for Manche72 revision 3 in NASA drawing 2021153G, ## which gives relatively high confidence that the reconstruction ## is correct. ## Assembler: yaYUL ## Contact: Ron Burkey <info@sandroid.org>. ## Website: www.ibiblio.org/apollo/index.html ## Mod history: 2024-05-19 MAS Created from Comanche 072. BANK 34 SETLOC MANUVER BANK 1146 EBANK= TEMPR60 COUNT 27/R60 # R60CSM # REV 13 CONFORMS TO GSOP CHAPTER FOUR REVISION LOGIC 09 JAN 18, 1968 >016468,000030: 27,2000 04725 R60CSM TC MAKECADR 55146 TS TEMPR60 # INSERT PRIODSP CHECK WITH R22 (V06N49) WITH JENNINGS BRODEUR E4E">016473,000035: 27,2002 35026 REDOMANN CAF BIT6 70101 MASK FLAGWRD5 # IS 3-AXIS FLAG SET 10000 CCS A 12013 TCF TOBALL # YES 06006 TC INTPRET 77624 CALL 56126 VECPOINT # TO COMPUTE FINAL ANGLES 01156 STORE CPHI # STORE FINAL ANGLES - CPHI, CTHETA, CPSI 77776 EXIT >016483,000045: 27,2013 32125 TOBALL CAF V06N18 04676 TC BANKCALL 21132 CADR GOPERF2R # DISPLAY PLEASE PERFORM AUTO MANEUVER 02114 TC R61TEST 02023 TC REDOMANC # PROCEED 12052 TCF ENDMANU1 # ENTER I.E. FINISHED WITH R60 02056 TC CHKLINUS # TO CHECK FOR PRIORITY DISPLAYS 05233 TC ENDOFJOB E43">016493,000055: 27,2023 35026 REDOMANC CAF BIT6 70101 MASK FLAGWRD5 # IS 3-AXIS FLAG SET 10000 CCS A 12034 TCF TOBALLC # YES 06006 TC INTPRET 77624 CALL 56126 VECPOINT # TO COMPUTE FINAL ANGLES 01156 STORE CPHI # STORE ANGLES 77776 EXIT 3">016503,000065: 27,2034 34371 TOBALLC CAF PRIO30 # IS MODE AUTO AND CTL GNC 00006 EXTEND 06031 RXOR CHAN31 77707 MASK 13,14,15 00006 EXTEND 12043 BZF +2 # AUTO, NON-FLASH N18 12013 TCF TOBALL # NOT AUTO 32125 CAF V06N18 # SET UP NON-FLASHING V06 N18 04676 TC BANKCALL 20676 CADR GODSPR 02056 TC CHKLINUS E56">016516,000078: 27,2047 04676 STARTMNV TC BANKCALL 17627 CADR GOMANUR 556">016518,000080: 27,2051 12013 ENDMANUV TCF TOBALL # FINISHED MANEUVER 531">016520,000082: 27,2052 05574 ENDMANU1 TC DOWNFLAG # RESET 3-AXIS FLAG 00124 ADRES 3AXISFLG # BIT 6 FLAG 5 31146 CAE TEMPR60 # - 04720 TC BANKJUMP # - 553">016525,000087: 27,2056 40100 CHKLINUS CS FLAGWRD4 75020 MASK BIT12 # IS PRIORITY DISPLAY FLAG SET - 10000 CCS A # - 00002 TC Q # NO - EXIT 30002 CA Q 54156 TS MPAC +2 # SAVE RETURN 46214 CS THREE # OBTAIN LOCATION FOR RESTART. 60133 AD BUF2 # HOLDS Q OF LAST DISPALY 55053 TS TBASE1 05426 TC PHASCHNG 00071 OCT 71 # 1.7SPOT FOR RELINUS 35025 CAF BIT7 05542 TC LINUS # GO SET BITS FOR PRIORITY DISPLAY - 00156 TC MPAC +2 3">016542,000104: 27,2074 35027 RELINUS CAF BIT5 # IS TRACK FLAG ON 70075 MASK FLAGWRD1 00006 EXTEND 12111 BZF GOREDO20 # NO 05562 TC UPFLAG 00077 ADRES PDSPFLAG # R60 PRIODSP FLAG 05562 TC UPFLAG 00024 ADRES TARG1FLG # FOR R52 35035 CAF ZERO # RESET TO ZERO, SINCE 55303 TS OPTIND # OPTIND WAS SET TO -1 BY V379 35102 CAF PRIO14 # RESTORE ORIGINAL PRIORITY 05224 TC PRIOCHNG 01053 TC TBASE1 230">016561,000123: 27,2111 05426 GOREDO20 TC PHASCHNG 00111 OCT 111 # 1.11 FOR PIKUP20 05233 TC ENDOFJOB 4">016566,000128: 27,2114 31011 R61TEST CA MODREG # ARE WE IN P00. IF YES THIS MUST BE 00006 EXTEND # VERB49 OR VERB89 SO DO ENDEXT. 12052 BZF ENDMANU1 # RESET 3-AXIS & RUTURN. USER DOES ENDEXT 30100 CA FLAGWRD4 # ARE WE IN R61 (P20) 75020 MASK BIT12 00006 EXTEND 14106 BZF GOTOPOOH # NO 04622 TC GOTOV56 # YES 7">016575,000137: 27,2124 20100 BIT14+7 OCT 20100 # - >016576,000138: 27,2125 01422 V06N18 VN 0618 # PROGRAM DESCRIPTION - VECPOINT # THIS INTERPRETIVE SUBROUTINE MAY BE USED TO POINT A SPACECRAFT AXIS IN A DESIRED DIRECTION. THE AXIS # TO BE POINTED MUST APPEAR AS A HALF UNIT DOUBLE PRECISION VECTOR IN SUCCESSIVE LOCATIONS OF ERASABLE MEMORY # BEGINNING WITH THE LOCATION CALLED SCAXIS. THE COMPONENTS OF THIS VECTOR ARE GIVEN IN SPACECRAFT COORDINATES. # THE DIRECTION IN WHICH THIS AXIS IS TO BE POINTED MUST APPEAR AS A HALF UNIT DOUBLE PRECISION VECTOR IN # SUCCESSIVE LOCATIONS OF ERASABLE MEMORY BEGINNING WITH THE ADDRESS CALLED POINTVSM. THE COMPONENTS OF THIS # VECTOR ARE GIVEN IN STABLE MEMBER COORDINATES. WITH THIS INFORMATION VECPOINT COMPUTES A SET OF THREE GIMBAL # ANGLES (2S COMPLEMENT) CORRESPONDING TO THE CROSS-PRODUCT ROTATION BETWEEN SCAXIS AND POINTVSM AND STORES THEM # IN T(MPAC) BEFORE RETURNING TO THE CALLER. # THIS ROTATION, HOWEVER, MAY BRING THE S/C INTO GIMBAL LOCK. WHEN POINTING A VECTOR IN THE Y-Z PLANE, # THE TRANSPONDER AXIS, OR THE AOT FOR THE LEM, THE PROGRAM WILL CORRECT THIS PROBLEM BY ROTATING THE CROSS- # PRODUCT ATTITUDE ABOUT POINTVSM BY A FIXED AMOUNT SUFFICIENT TO ROTATE THE DESIRED S/C ATTITUDE OUT OF GIMBAL # LOCK. IF THE AXIS TO BE POINTED IS MORE THAN 40.6 DEGREES BUT LESS THAN 60.5 DEG FROM THE +X (OR -X) AXIS, # THE ADDITIONAL ROTATION TO AVOID GIMAL LOCK IS 35 DEGREES. IF THE AXIS IS MORE THAN 60.5 DEGEES FROM +X (OR -X) # THE ADDITIONAL ROTATION IS 35 DEGREES. THE GIMBAL ANGLES CORRESPONDING TO THIS ATTITUDE ARE THEN COMPUTED AND # STORED AS 2S COMPLIMENT ANGLES IN T(MPAC) BEFORE RETURNING TO THE CALLER. # WHEN POINTING THE X-AXIS, OR THE THRUST VECTOR, OR ANY VECTOR WITHIN 40.6 DEG OF THE X-AXIS, VECPOINT # CANNOT CORRECT FOR A CROSS-PRODUCT ROTATION INTO GIMBAL LOCK. IN THIS CASE A PLATFORM REALIGNMENT WOULD BE # REQUIRED TO POINT THE VECTOR IN THE DESIRED DIRECTION. AT PRESENT NO INDICATION IS GIVEN FOR THIS SITUATION # EXCEPT THAT THE FINAL MIDDLE GIMBAL ANGLE IN MPAC +2 IS GREATER THAN 59 DEGREES. # CALLING SEQUENCE - # 1) LOAD SCAXIS, POINTVSM # 2) CALL # VECPOINT # RETURNS WITH # 1) DESIRED OUTER GIMBAL ANGLE IN MPAC # 2) DESIRED INNER GIMBAL ANGLE IN MPAC +1 # 3) DESIRED MIDDLE GIMBAL ANGLE IN MPAC +2 # ERASABLES USED - # 1) SCAXIS 6 # 2) POINTVSM 6 # 3) MIS 18 # 4) DEL 18 # 5) COF 6 # 6) VECQTEMP 1 # 7) ALL OF VAC AREA 43 # TOTAL 99 SETLOC VECPT BANK EBANK= BCDU COUNT 27/VECPT E54">016632,000194: 27,2126 40020 VECPOINT STQ BOV # SAVE RETURN ADDRESS 03310 VECQTEMP 56131 VECLEAR # AND CLEAR OVFIND 2">016635,000197: 27,2131 47164 VECLEAR AXC,2 RTB 03320 MIS # READ THE PRESENT CDU ANGLES AND 44376 READCDUK # STORE THEM IN PD25, 26, 27 34032 STCALL 25D 44405 CDUTODCM # S/C AXES TO STABLE MEMBER AXES (MIS) 61375 VLOAD VXM 03357 POINTVSM # RESOLVE THE POINTING DIRECTION VF INTO 03321 MIS # INITIAL S/C AXES (VF = POINTVSM) 77656 UNIT 00035 STORE 28D # PD 28 29 30 31 32 33 53435 VXV UNIT # TAKE THE CROSS PRODUCT VF X VI 03351 SCAXIS # WHERE VI = SCAXIS 57400 BOV VCOMP 56256 PICKAXIS 17343 STODL COF # CHECK MAGNITUDE 00045 36D # OF CROSS PRODUCT 50025 DSU BMN # VECTOR, IF LESS 16327 DPB-14 # THAN B-14 ASSUME 56256 PICKAXIS # UNIT OPERATION 50375 VLOAD DOT # INVALID. 03351 SCAXIS 00035 28D 65552 SL1 ARCCOS 458">016659,000221: 27,2160 77624 COMPMATX CALL # NOW COMPUTE THE TRANSFORMATION FROM 44530 DELCOMP # FINAL S/C AXES TO INITIAL S/C AXES MFI 75160 AXC,1 AXC,2 03320 MIS # COMPUTE THE TRANSFORMATION FROM FINAL 03425 DEL # S/C AXES TO STABLE MEMBER AXES 77624 CALL # MFS = MIS MFI 44304 MXM3 # (IN PD LIST) 51545 DLOAD ABS 00007 6 # MFS6 = SIN(CPSI) $2 50025 DSU BMN 16314 SINGIMLC # = SIN(59 DEGS) $2 56246 FINDGIMB # /CPSI/ LESS THAN 59 DEGS # I.E. DESIRED ATTITUDE NOT IN GIMBAL LOCK 51545 DLOAD ABS # CHECK TO SEE IF WE ARE POINTING 03351 SCAXIS # THE THRUST AXIS 51025 DSU BPL 16316 SINVEC1 # SIN 49.4 DEGS $2 56246 FINDGIMB # IF SO, WE ARE TRYING TO POINT IT INTO 77775 VLOAD # GIMBAL LOCK, ABORT COULD GO HERE 77626 STADR 50442 STOVL MIS +12D 77626 STADR # STORE MFS (IN PD LIST) IN MIS 50450 STOVL MIS +6 77626 STADR 50456 STOVL MIS 03327 MIS +6 # INNER GIMBAL AXIS IN FINAL S/C AXES 57444 BPL VCOMP # LOCATE THE IG AXIS DIRECTION CLOSEST TO 56213 IGSAMEX # FINAL X S/C AXIS 8">016690,000252: 27,2213 50035 IGSAMEX VXV BMN # FIND THE SHORTEST WAY OF ROTATING THE 03351 SCAXIS # S/C OUT OF GIMBAL LOCK BY A ROTATION 56222 U=SCAXIS # ABOUT +- SCAXIS, I.E. IF (IG (SGN MFS3) # X SCAXIS . XF) LESS THAN 0, U = SCAXIS # OTHERWISE U = -SCAXIS 57575 VLOAD VCOMP 03351 SCAXIS 37343 STCALL COF # ROTATE ABOUT -SCAXIS 56225 CHEKAXIS 953">016700,000262: 27,2222 77775 U=SCAXIS VLOAD 03351 SCAXIS 03343 STORE COF # ROTATE ABOUT + SCAXIS 953">016703,000265: 27,2225 51545 CHEKAXIS DLOAD ABS 03351 SCAXIS # SEE IF WE ARE POINTING THE AOT 51025 DSU BPL 16320 SINVEC2 # SIN 29.5 DEGS $2 56235 PICKANG1 # IF SO, ROTATE 50 DEGS ABOUT +- SCAXIS 52145 DLOAD GOTO # IF NOT, MUST BE POINTING THE TRANSPONDER 16324 VECANG2 # OR SOME VECTOR IN THE Y, OR Z PLANE 56237 COMPMFSN # IN THIS CASE ROTATE 35 DEGS TO GET OUT # OF GIMBAL LOCK (VECANG2 $360) 731">016712,000274: 27,2235 77745 PICKANG1 DLOAD 16322 VECANG1 # = 50 DEGS $ 360 34E">016714,000276: 27,2237 77624 COMPMFSN CALL 44530 DELCOMP # COMPUTE THE ROTATION ABOUT SCAXIS TO 75160 AXC,1 AXC,2 # BRING MFS OUT OF GIMBAL LOCK 03320 MIS 03425 DEL 77624 CALL # COMPUTE THE NEW TRANSFORMATION FROM 44304 MXM3 # DESIRED S/C AXES TO STABLE MEMBER AXES # WHICH WILL ALIGN VI WITH VF AND AVOID # GIMBAL LOCK D42">016723,000285: 27,2246 45160 FINDGIMB AXC,1 CALL 00000 0 # EXTRACT THE COMMANDED CDU ANGLES FROM 44655 DCMTOCDU # THIS MATRIX 40234 RTB SETPD 45552 V1STO2S # CONVERT TO 2:S COMPLEMENT 00001 0 77650 GOTO 03310 VECQTEMP # RETURN TO CALLER 953">016732,000294: 27,2256 50375 PICKAXIS VLOAD DOT # IF VF X VI = 0, FIND VF . VI 00035 28D 03351 SCAXIS 72240 BMN TLOAD 56266 ROT180 00032 25D 77650 GOTO # IF VF = VI, CDU DESIRED = PRESENT CDU 03310 VECQTEMP # PRESENT CDU ANGLES >016741,000303: 27,2266 47375 ROT180 VLOAD VXV # IF VF, VI ANTIPARALLEL, 180 DEG ROTATION 03327 MIS +6 # IS REQUIRED. Y STABLE MEMBER AXIS IN 15332 HIUNITX # INITIAL S/C AXIS. 47256 UNIT VXV # FIND Y(SM) X X(I) 03351 SCAXIS # FIND UNIT(VI X UNIT(Y(SM) X X(I))) 40056 UNIT BOV # I.E. PICK A VECTOR IN THE PLANE OF X(I), 56310 PICKX # Y(SM) PERPENDICULAR TO VI 17343 STODL COF 00045 36D # CHECK MAGNITUDE 50025 DSU BMN # OF THIS VECTOR. 16327 DPB-14 # IF LESS THAN B-14, 56310 PICKX # PICK X-AXIS. 77775 VLOAD 03343 COF >016755,000317: 27,2304 17343 XROT STODL COF 15332 HIDPHALF 77650 GOTO 56160 COMPMATX /a>016759,000321: 27,2310 52175 PICKX VLOAD GOTO # PICK THE XAXIS IN THIS CASE 15332 HIUNITX 56304 XROT BANK 35 SETLOC MANUVER1 BANK C43">016766,000328: 27,2313 15555 35172 SINGIMLC 2DEC .4285836003 # = SIN(59) $2 1">016768,000330: 27,2315 14113 36326 SINVEC1 2DEC .3796356537 # = SIN(49.4) $2 2">016770,000332: 27,2317 07701 35703 SINVEC2 2DEC .2462117800 # = SIN(29.5) $2 1">016772,000334: 27,2321 04343 21616 VECANG1 2DEC .1388888889 # = 50 DEGREES $360 2">016774,000336: 27,2323 03070 34344 VECANG2 2DEC .09722222222 # = 35 DEGREES $360 >016777,000339: 27,2325 00000 1BITDP OCT 0 # KEEP THIS BEFORE DPB(-14) ********* >016778,000340: 27,2326 00001 DPB-14 OCT 00001 00000 OCT 00000 BANK 34 SETLOC MANUVER BANK # ROUTINE FOR INITIATING AUTOMATIC MANEUVER VIA KEYBOARD (V49) 1155 EBANK= CPHI COUNT 27/R62 0">016790,000352: 27,2330 35066 R62DISP CAF V06N22 # DISPLAY COMMAND ICDUS CPHI, CTHETA, CPHI 04676 TC BANKCALL 20720 CADR GOFLASH 15550 TCF ENDEXT 12336 TCF GOMOVE # PROCEED 12330 TCF R62DISP # ENTER # ASTRONAUT MAY LOAD NEW ICDUS AT THIS # POINT >016799,000361: 27,2336 05562 GOMOVE TC UPFLAG # SET 3-AXIS FLAG 00124 ADRES 3AXISFLG # BIT 6 FLAG 5 04676 TC BANKCALL 56000 CADR R60CSM 15550 TCF ENDEXT Parent file is MAIN.agc