# Copyright: Public domain. # Filename: RTB_OP_CODES.agc # Purpose: Part of the source code for Luminary 1A build 099. # It is part of the source code for the Lunar Module's (LM) # Apollo Guidance Computer (AGC), for Apollo 11. # Assembler: yaYUL # Contact: Ron Burkey . # Website: www.ibiblio.org/apollo. # Pages: 1397-1401 # Mod history: 2009-05-10 SN (Sergio Navarro). Started adapting # from the Luminary131/ file of the same # name, using Luminary099 page images. # # This source code has been transcribed or otherwise adapted from # digitized images of a hardcopy from the MIT Museum. The digitization # was performed by Paul Fjeld, and arranged for by Deborah Douglas of # the Museum. Many thanks to both. The images (with suitable reduction # in storage size and consequent reduction in image quality as well) are # available online at www.ibiblio.org/apollo. If for some reason you # find that the images are illegible, contact me at info@sandroid.org # about getting access to the (much) higher-quality images which Paul # actually created. # # Notations on the hardcopy document read, in part: # # Assemble revision 001 of AGC program LMY99 by NASA 2021112-61 # 16:27 JULY 14, 1969 # Page 1397 BANK 22 SETLOC RTBCODES BANK EBANK= XNB COUNT* $$/RTB # LOAD TIME2, TIME1 INTO MPAC: LOADTIME EXTEND DCA TIME2 TCF SLOAD2 # CONVERT THE SINGLE PRECISION 2'S COMPLEMENT NUMBER ARRIVING IN MPAC (SCALED IN HALF-REVOLUTIONS) TO A # DP 1'S COMPLEMENT NUMBER SCALED IN REVOLUTIONS. CDULOGIC CCS MPAC CAF ZERO TCF +3 NOOP CS HALF TS MPAC +1 CAF ZERO XCH MPAC EXTEND MP HALF DAS MPAC TCF DANZIG # MODE IS ALREADY AT DOUBLE-PRECISION # FORCE TP SIGN AGREEMENT IN MPAC: SGNAGREE TC TPAGREE TCF DANZIG # CONVERT THE DP 1'S COMPLEMENT ANGLE SCALED IN REVOLUTIONS TO A SINGLE PRECISION 2'S COMPLEMENT ANGLE # SCALED IN HALF-REVOLUTIONS. 1STO2S TC 1TO2SUB CAF ZERO TS MPAC +1 TCF NEWMODE # DO 1STO2S ON A VECTOR OF ANGLES: V1STO2S TC 1TO2SUB # ANSWER ARRIVES IN A AND MPAC. DXCH MPAC +5 DXCH MPAC TC 1TO2SUB # Page 1398 TS MPAC +2 DXCH MPAC +3 DXCH MPAC TC 1TO2SUB TS MPAC +1 CA MPAC +5 TS MPAC TPMODE CAF ONE # MODE IS TP. TCF NEWMODE # V1STO2S FOR 2 COMPONENT VECTOR. USED BY RR. 2V1STO2S TC 1TO2SUB DXCH MPAC +3 DXCH MPAC TC 1TO2SUB TS L CA MPAC +3 TCF SLOAD2 # SUBROUTINE TO DO DOUBLING AND 1'S TO 2'S CONVERSION: 1TO2SUB DXCH MPAC # FINAL MPAC +1 UNSPECIFIED. DDOUBL CCS A AD ONE TCF +2 COM # THIS WAS REVERSE OF MSU. TS MPAC # AND SKIP ON OVERFLOW. TC Q INDEX A # OVERFLOW UNCORRECT AND IN MSU. CAF LIMITS ADS MPAC TC Q # THE FOLLOWING ROUTINE INCREMENTS IN 2S COMPLEMENT THE REGISTER WHOSE ADDRESS IS IN BUF BY THE 1S COMPL. # QUANTITY FOUND IN TEM2. THIS MAY BE USED TO INCREMENT DESIRED IMU AND OPTICS CDU ANGLES OR ANY OTHER 2S COMPL. # (+0 UNEQUAL TO -0) QUANTITY. MAY BE CALLED BY BANKCALL/SWCALL. CDUINC TS TEM2 # 1S COMPL.QUANT. ARRIVES IN ACC. STORE IT INDEX BUF CCS 0 # CHANGE 2S COMPL. ANGLE(IN BUF)INTO 1S AD ONE TCF +4 AD ONE # Page 1399 AD ONE # OVERFLOW HERE IF 2S COMPL. IS 180 DEG. COM AD TEM2 # SULT MOVES FROM 2ND TO 3D QUAD. (OR BACK) CCS A # BACK TO 2S COMPL. AD ONE TCF +2 COM TS TEM2 # STORE 14BIT QUANTITY WITH PRESENT SIGN TCF +4 INDEX A # SIGN. CAF LIMITS # FIX IT, BY ADDING IN 37777 OR 40000 AD TEM2 INDEX BUF TS 0 # STORE NEW ANGLE IN 2S COMPLEMENT. TC Q # Page 1400 # RTB TO TORQUE GYROS, EXCEPT FOR THE CALL TO IMUSTALL. ECADR OF COMMANDS ARRIVES IN X1. PULSEIMU INDEX FIXLOC # ADDRESS OF GYRO COMMANDS SHOULD BE IN X1 CA X1 TC BANKCALL CADR IMUPULSE TCF DANZIG # Page 1401 # THE SUBROUTINE SIGNMPAC SETS C(MPAC, MPAC +1) TO SIGN(MPAC). # FOR THIS, ONLY THE CONTENTS OF MPAC ARE EXAMINED. ALSO +0 YIELDS POSMAX AND -0 YIELDS NEGMAX. # # ENTRY MAY BE BY EITHER OF THE FOLLOWING: # 1. LIMIT THE SIZE OF MPAC ON INTERPRETIVE OVERFLOW: # ENTRY: BOVB # SIGNMPAC # 2. GENERATE IN MPAC THE SIGNUM FUNCTION OF MPAC: # ENTRY: RTB # SIGNMPAC # IN EITHER CASE, RETURN IS TO THE NEXT INTERPRETIVE INSTRUCTION IN THE CALLING SEQUENCE. SIGNMPAC EXTEND DCA DPOSMAX DXCH MPAC CCS A DPMODE CAF ZERO # SETS MPAC +2 TO ZERO IN THE PROCESS TCF SLOAD2 +2 TCF +1 EXTEND DCS DPOSMAX TCF SLOAD2 # RTB OP CODE NORMUNIT IS LIKE INTERPRETIVE INSTRUCTION UNIT, EXCEPT THAT IT CAN BE DEPENDED ON NOT TO BLOW # UP WHEN THE VECTOR BEING UNITIZED IS VERY SMALL -- IT WILL BLOW UP WHEN ALL COMPONENT ARE ZERO. IF NORMUNIT # IS USED AND THE UPPER ORDER HALVES OF ALL COMPONENTS ARE ZERO, THE MAGNITUDE RETURNED IN 36D WILL BE TOO LARGE # BY A FACTOR OF 2(13) AND THE SQUARED MAGNITUDE RETURNED ATE 34D WILL BE TOO BIG BY A FACTOR OF 2(26). NORMUNX1 CAF ONE TCF NORMUNIT +1 NORMUNIT CAF ZERO AD FIXLOC TS MPAC +2 TC BANKCALL # GET SIGN AGREEMENT IN ALL COMPONENTS CADR VECAGREE CCS MPAC TCF NOSHIFT TCF +2 TCF NOSHIFT CCS MPAC +3 TCF NOSHIFT TCF +2 TCF NOSHIFT CCS MPAC +5 TCF NOSHIFT TCF +2 TCF NOSHIFT # Page 1402 CA MPAC +1 # SHIFT ALL COMPONENTS LEFT 13 EXTEND MP BIT14 DAS MPAC # DAS GAINS A LITTLE ACCURACY CA MPAC +4 EXTEND MP BIT14 DAS MPAC +3 CA MPAC +6 EXTEND MP BIT14 DAS MPAC +5 CAF THIRTEEN INDEX MPAC +2 TS 37D OFFTUNIT TC POSTJUMP CADR UNIT +1 # SKIP THE "TC VECAGREE" DONE AT UNIT NOSHIFT CAF ZERO TCF OFFTUNIT -2 # RTB VECSGNAG ... FORCES SIGN AGREEMENT OF VECTOR IN MPAC. VECSGNAG TC BANKCALL CADR VECAGREE TC DANZIG # *** END OF SKIPPER .087 ***