File: CS.PA of Tape: OS8/OS8-V3D/al-4693d-sa-os8-v3d-3
(Source file text)
/4 OS/8 CASSETTE HANDLER / / / / / / / / / /COPYRIGHT (C) 1974,1975 BY DIGITAL EQUIPMENT CORPORATION / / / / / / / / / / /THE INFORMATION IN THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE /AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY DIGITAL EQUIPMENT /CORPORATION. DIGITAL EQUIPMENT CORPORATION ASSUMES NO RESPONSIBILITY /FOR ANY ERRORS THAT MAY APPEAR IN THIS DOCUMENT. / /THE SOFTWARE DESCRIBED IN THIS DOCUMENT IS FURNISHED TO THE PURCHASER /UNDER A LICENSE FOR USE ON A SINGLE COMPUTER SYSTEM AND CAN BE COPIED /(WITH INCLUSION OF DIGITAL'S COPYRIGHT NOTICE) ONLY FOR USE IN SUCH /SYSTEM, EXCEPT AS MAY OTHERWISE BE PROVIDED IN WRITING BY DIGITAL. / /DIGITAL EQUIPMENT CORPORATION ASSUMES NO RESPONSIBILITY FOR THE USE /OR RELIABILITY OF ITS SOFTWARE ON EQUIPMENT THAT IS NOT SUPPLIED BY /DIGITAL. / / / / / / / / / / / DEC-S8-UCASA-A-LA / COPYRIGHT 1972 / DIGITAL EQUIPMENT CORPORATION / MAYNARD MASSACHUSETTS 01754 / MOUTH/DORP IFNDEF CODE <CODE=0> KCLR=CODE^10+6700 /CLEAR ALL KSDR=CODE^10+6701 /SKIP ON DATA FLAG KSEN=CODE^10+6702 /SKIP ON ERROR KSBF=CODE^10+6703 /SKIP ON READY FLAG KLSA=CODE^10+6704 /LOAD STATUS A KSAF=CODE^10+6705 /SKIP ON ANY FLAG OR ERROR KGOA=CODE^10+6706 /ASSERT CONTENTS OF STATUS A AND XFER KRSB=CODE^10+6707 /READ STATUS B BSW=7002 /BYTE SWAP [8/E,F ONLY] /REWIND=10 /BACKFIL=30 /WRGAP=40 /BACKBLOCK=50 /SKPFIL=70 /SPECIAL CODES / 0 WRITE EOF / 1 REWIND / 2 BACKBLOCK / 3 SKIPFILE/BACKFILE / 4-7 UNUSED (TAKES LOW ORDER 2 BITS ONLY CURRENTLY) VERSION="C&77 *0 -2 /THERE ARE TWO HANDLERS 2401 7001+CODE 0323 0160+CODE+CODE /CSA0 270 /DEVICE CONTROL BLOCK (TYPE 27) 4000+7 /ENTRY POINT FOR CSA0 ZBLOCK 2 2401 7001+CODE 0323 0161+CODE+CODE /CSA1 270 4000+1 /ENTRY POINT FOR CSA1 ZBLOCK 2 *200 K3700, 3700 /MUST BE FIRST LOCATION ON PAGE UNIT, CSA1, VERSION /ENTRY POINT FOR CSA1 CLA /PROTECT CODE AGAINST IGNORANT USERS TAD CSA1 /PICK UP ARGUMENTS DCA CSA0 /VIA CSA0 STL IAC RAL /TAD (3 [8/I,L,E,F] JMP .+3 /JOIN PROCESSING WITH UNIT 1 CSA0, VERSION /ENTRY POINT FOR CSA0 STL CLA RTL /TAD (2 BSW / [8/E,F] DCA UNIT /SAVE UNIT (0 IS 200, 1 IS 300) CS, JMS T /INITIALIZATION; REPLACED BY RDF TAD KCIF /FORM RETURN FIELD INSTRUCTION DCA RETCIF /STORE IN RETURN CODE TAD I CSA0 /GET FUNCTION CONTROL WORD DCA FUN /SAVE IT TAD FUN /GET IT BACK AGAIN AND K70 /ISOLATE FIELD OF BUFFER TAD KCDF /FORM CDF TO FIELD OF BUFFER DCA BUFCDF /STORE IN APPROPRIATE SPOT ISZ CSA0 /POINT TO ARGUMENT 2 TAD I CSA0 /GET BUFFER ADDRESS DCA BUFFER /SAVE IT ISZ CSA0 /POINT TO ARGUMENT 3 TAD I CSA0 /GET BLOCK NUMBER ISZ CSA0 /POINT TO ERROR RETURN KCIF, CIF CDF 0 /SEEK TEMPORARY SAFETY IN CURRENT DATA FIELD SZA CLA JMP NOT1ST /NOT BLOCK 0 STL CLA RAR /TAD (4000 AND FUN /ISOLATE READ/WRITE BIT TAD UNIT /INSERT UNIT JMS I QCAS /CALL CASSETTE ROUTINE REWIND-. /TO PERFORM A REWIND/INITIALIZATION NOT1ST, TAD FUN K200, AND K3700 /ISOLATE NUMBER OF BLOCKS TO XFER SNA JMP SPCASE /0 BLOCKS MEANS SPECIAL THING (EOF) RECLP, DCA BLKNT /SET COUNT OF NUMBER OF BLOCKS STL CLA RAR /TAD (4000 AND FUN /ISOLATE READ/WRITE BIT TAD UNIT /INSERT UNIT JMS I QCAS /CALL CASSETTE ROUTINE RW-. /TO INITIATE READ OR WRITE RETRY, SZA /NON-ZERO AC MEANS ERROR JMP RETCIF /TOUGH LUCK BOOBIE - ERROR TAD K7700 /GET READY TO XFER 100 DOUBLE WORDS DCA DBWDCT /SET DOUBLE WORD COUNTER TAD BUFFER /GET START OF BUFFER SEGMENT DCA BPTR /SET 'BPTR' BUFCDF, HLT /CHANGE TO DATA FIELD OF USER'S BUFFER TAD FUN K7700, SMA CLA /WHICH DIRECTION IS TRANSFER? JMP READ /WANT TO READ WRITE, TAD I BPTR /WANT TO WRITE, SO GET WORD FROM BUFFER JMS I QGPCH /WRITE TAD I BPTR /GET FIRST WORD AGAIN AND P7400 /ISOLATE FIRST HALF OF BYTE 3 DCA T /SAVE FOR FUTURE REFERENCE ISZ BPTR /POINT TO NEXT LOCATION IN BUFFER TAD I BPTR /GET SECOND WORD OF BUFFER PAIR JMS I QGPCH /WRITE BYTE #2 TAD I BPTR /RETRIEVE WORD 2 AND P7400 /ISOLATE 2ND HALF OF BYTE #3 CLL RTR /CREATE MYSTIC HIDDEN BYTE 3 RTR TAD T /GOOD THING I STILL HAVE THIS CLL RTR RTR JMS I QGPCH /WRITE BYTE #3 JMP COM READ, JMS I QGPCH /READ BYTE #1 OF TRIPLE DCA I BPTR /STORE IN WORD 1 OF BUFFER PAIR JMS I QGPCH /READ BYTE #2 OF TRIPLE DCA T /SAVE IT FOR POSTERITY JMS I QGPCH /READ BYTE #3 OF TRIPLE RTL RTL /MYSTIC ROTATES DCA T2 TAD T2 AND P7400 /AND MYSTIC CONSTANTS TAD I BPTR /FIX UP BUFFER WORD 1 OF PAIR DCA I BPTR TAD T2 RTL RTL /MORE ROTATION AND P7400 /AND MORE TAD T ISZ BPTR /POINT TO SECOND WORD OF BUFFER PAIR DCA I BPTR /STORE SECOND WORD COM, ISZ BPTR /POINT TO BEGIN OF NEXT BUFFER PAIR P7400, 7400 /PROTECTION AGAINST CORE WRAP AROUND ISZ DBWDCT /BUMP DOUBLE WORD COUNT JMP BUFCDF /REITERATE JMS I QCAS /CALL CASSETTE ROUTINE CRC-. /TO CHECK CRC TAD BUFFER /GET BUFFER SEGMENT ADDRESS TAD K200 /ADD 200 TO GET TO NEXT SEGMENT DCA BUFFER /REPLACE TAD BLKNT /GET BLOCK COUNT TAD K7700 /SUBTRAT 100 SZA /ARE WE DONE? JMP RECLP /NO, REITERATE ISZ CSA0 /POINT TO NORMAL GOOD RETURN RETCIF, HLT /RETURN TO USER'S DATA AND INSTRUCTION FIELDS JMP I CSA0 /RETURN / INTIALIZATION ROUTINE - ONCE ONLY CODE / OVERLAID BY TEMPORARIES T, 0 /ENTRY POINT TO INITIALIZATION T2, TAD KRDF /REPLACE CALL BY RDF FUN, DCA CS /SO THAT WE'LL NEVER SEE YOU HERE AGAIN BUFFER, TAD T /CORRECT ADDRESS OF GPCH DBWDCT, TAD KQX1 /BY ADDING IN CS+1 QGPCH, DCA . /STORE IT HERE BLKNT, STL CLA RTL /CORRECT ADDRESS OF CAS IS 2 MORE TAD QGPCH QCAS, DCA . /THAN GPCH. STORE IT HERE. BPTR, JMP CS /RETURN TO MAIN PROGRAM KRDF, RDF KQX1, GPCH-CS-1 SPCASE, TAD FUN AND L4003 /ISOLATE R/W BIT + SPECIAL CODE TAD UNIT JMS I QCAS SPCODE-. JMP RETCIF-1 /LEAVE GRACEFULLY K70, 70 KCDF, CDF 0 L4003, 4003 PAGE GPCH, 0 /READ OR WRITE A BYTE JMP AROUND /GO TO REAL LOCATION OF THIS SUBROUTINE CAS, 0 /MUST BE AT GPCH+2; DO CASSETTE STUFF DCA TEMP /SAVE ARGUMENT IN AC CDF 0 TAD I CAS /GET UNRELOCATED RELATIVE LOCAL ENTRY POINT TAD CAS /RELOCATE IT ISZ CAS /POINT TO NORMAL RETURN LOCATION DCA GPCH /SAVE ENTRY POINT IN TEMPORARY JMP I GPCH /GO TO CORRECT ENTRY POINT RW, TAD CAS DCA RTRY /SAVE RETRY ADDRESS TAD TEMP /GET ARGUMENT PASSED VIA AC DCA FNUNIT /SAVE CLL STA RTL /TAD (7775 DCA ERKNT /SET ERROR COUNT TO -3 ERETRY, TAD FNUNIT SPA TAD (20 /READ CODE IS 0; WRITE IS 20 KLSA /LOAD STATUS A TAD FNUNIT /***KLSA CLEARS BIT 0 SMA CLA /READS HAVE TO BE INITIATED JMS CWAIT /READ JMP I RTRY /RETURN AROUND, DCA TEMP TAD FNUNIT SMA CLA JMP RDCHAR /READ TAD TEMP /WRITE JMS CWAIT JMP I GPCH /RETURN RDCHAR, JMS CWAIT TAD TEMP /GET CHAR JUST READ JMP I GPCH /RETURN WITH IT IN AC CRC, TAD FNUNIT TAD (60 KLSA /INITIATE READ/WRITE CRC TAD FNUNIT /***KLSA CLEARS BIT 0 SMA CLA JMS CWAIT /HAVE TO READ TWICE JMS CWAIT /WRITE CRC WRITES BOTH KCLR /WHY NOT? JMP I CAS /RETURN REWIND, TAD (10 JMS UTIL TAD TEMP SMA CLA JMP I CAS /MERELY REWIND IF READING JMP EOF SKIPF, TAD (20 BACKBL, TAD (10 EOF, TAD (10 BACKF, TAD (30 JMS UTIL JMP I CAS /RETURN UTIL, 0 TAD TEMP KLSA TRYAGN, KGOA JMS CTCTST KSBF /WAIT FOR READY JMP .-2 KRSB AND (10 SZA CLA JMP TRYAGN /KEEP TRYING IF ERROR CAUSED BY DRIVE EMPTY JMP I UTIL TEMP, 0 ERKNT, 0 FNUNIT, 0 RTRY, 0 SPCODE, TAD TEMP AND (3 TAD (JMP TABLE DCA J TAD TEMP AND (4300 DCA TEMP J, HLT TABLE, JMP EOF /0 WRITE EOF JMP REWIND /1 REWIND AND WRITE EOF IF BIT 0=1 JMP BACKBL /2 BACK BLOCK TAD TEMP /3 SKIP/BACK FILE DEPENDING ON BIT 0 SMA CLA JMP SKIPF /FORWARD FILE JMP BACKF /BACK FILE CWAIT, 0 KGOA /ASSERT CONTENTS OF STATUS A DCA TEMP /SAVE ANYTHING READ JMS CTCTST KSAF JMP .-2 /WAIT FOR SOMETHING TO HAPPEN KSEN /WAS IT AN ERROR? JMP I CWAIT /NO, SO RETURN ERR, DCA TEMP /YES ... ERROR KRSB AND (30 SNA JMP .+3 AND (20 JMP I RTRY /END OF FILE IS SOFT ERROR ISZ ERKNT /SHALL WE TRY AGAIN? JMP .+3 /YES STL CLA RAR /TAD (4000 JMP I RTRY /RETURN WITH NON-ZERO AC TAD FNUNIT /RETRY TAD (50 /BUT FIRST DO BACKSPACE BLOCK GAP JMS UTIL JMP ERETRY CTCTST, 0 /TEST FOR CONTROL/C L7600, 7600 TAD L7600 KRS TAD (-7603 SNA CLA KSF JMP I CTCTST CIF CDF 0 JMP I L7600 /RETURN TO OS/8 $