File: TM8E.PA of Tape: OS8/OS8-Latest/new-12
(Source file text)
/TM8-E MAGTAPE HANDLER FOR OS/8 / / / / / / / / / / / / /COPYRIGHT (C) 1975 BY DIGITAL EQUIPMENT CORPORATION / AND 1979 BY DATAPLAN GMBH / / / / / / / / / /THE INFORMATION IN THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE /AND SHOULD NOT BE CONTRUED 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. / / / / / LWCR=6701 /LOAD WORD COUNT REGISTER AND CLEAR AC LCAR=6703 /LOAD CURRENT ADDRESS REGISTER AND CLEAR AC LCMR=6705 /LOAD COMMAND REGISTER AND CLEAR AC LFGR=6706 /LOAD FUNCTION REGISTER AND CLEAR AC CLT=6712 /CLEAR TRANSPORT RMSR=6714 /CLEAR AC AND READ MAIN STATUS REGISTER RFSR=6716 /CLEAR AC AND READ STUFF SKEF=6721 /SKIP IF ERROR FLAG IS SET SKJD=6723 /SKIP IF THE JOB IS DONE (MTTF IS SET) SKTR=6724 /SKIP IF TAPE UNIT READY (TUR TRUE) MTAVERSION="M&77 /SPECIAL CODES USED WHEN PAGE COUNT=0 (CODES IN BITS 9-11 OF FN WORD) /0 (CLOSE) WRITE 2 EOF'S /1 REWIND /2 SPACE FORWARD/REVERSE RECORDS / IF BIT 0 OF THE FUNCTION WORD IS A 0, / THIS CODE ADVANCES RECORDS. / THE NEGATIVE OF THE NUMBER OF RECODRDS IS SPECIFIED IN ARG 3 / IF BIT 0 OF THE FUNCTION WORD IS A 1, / THIS CODE BACKSPACES RECORDS. / THE NEGATIVE OF THE NUMBER OF RECORDS IS SPECIFIED AS ARG 3. / UNDER NO CIRCUMSTANCES DOES THIS COMMAND CONTINUE PAST A FILE MARK. /3 SPACE FORWARD/REVERSE FILES / IF BIT 0 OF THE FUNCTION WORD IS A 0 / THEN THIS FUNCTION ADVANCE FILE MARKS / THE NEGATIVE OF THE NUMBER OF FILE MARKS IS SPECIFIED BY ARG3 / THE TAPE IS LEFT POSITIONED AFTER THIS FILE MARK / BUT UNDER NO CIRCUMSTANCES DOES THE TAPE ADVANCE PAST / THE SECOND MARK OF TWO CONSECUTIVE FILE MARKS / IF BIT 0 OF THE FUNCTION WORD IS A 1, / THIS CODE BACKSPACES PAST FILE MARKS. / THE NEGATIVE OF THE NUMBER OF FILE MARKS IS SPECIFIED BY ARG 3. / THE TAPE IS LEFT POSITIONED BEFORE THE LAST FILE MARK, / SO THE USER PROBABLY WANTS TO DO A FORWARD RECORD NEXT. /4 REWIND AND PUT OFF-LINE /5 WRITE EOF /6 PERFORM OPERATION WITH SPECIFIED BLOCKSIZE / THE NEGATIVE OF THE DESIRED BLOCKSIZE IS SPECIFIED AS ARG 3. /7 CURRENTLY UNUSED /NOTE: SKIP TO EOD CAN BE PERFORMED BY SKIPPING 4096 FILES /MAINTENANCE RELEASE CHANGES: /1. MAJOR CODE OVERHAUL /2. SKIP RECORDS RETURNS NON-FATAL ERROR IF IT DETECTS FILE MARK /3. SKIP FORWARD FILES NEVER EVER PASSES EOD /4. SKIP FORWARD FILES RETURNS ERROR IF IT STARTS IMMEDIATELY / BEFORE A FILE MARK (UNLESS IT'S AT BOT) / IT THEN REMAINS BEFORE THE FILE MARK /5. FIXED TIMING PROBLEM FOR TS03 /6. CHANGED ORDER OF TEST FOR DATA DURING SKIP FORWARD FILES /7. MADE UNUSED FUNCTION CODE 7 ACT SAME AS 0 /BUILD DESCRIPTOR BLOCK *0 -10 /8 ENTRY POINTS DEVICE TM8E;DEVICE MTA0;200;MTA0&177+4000;ZBLOCK 2 DEVICE TM8E;DEVICE MTA1;200;MTA1&177+4000;ZBLOCK 2 DEVICE TM8E;DEVICE MTA2;200;MTA2&177+4000;ZBLOCK 2 DEVICE TM8E;DEVICE MTA3;200;MTA3&177+4000;ZBLOCK 2 DEVICE TM8E;DEVICE MTA4;200;MTA4&177+4000;ZBLOCK 2 DEVICE TM8E;DEVICE MTA5;200;MTA5&177+4000;ZBLOCK 2 DEVICE TM8E;DEVICE MTA6;200;MTA6&177+4000;ZBLOCK 2 DEVICE TM8E;DEVICE MTA7;200;MTA7&177+4000;ZBLOCK 2 *200 PARITY, 402 /CHANGE TO 2 TO HAVE EVEN PARITY BLOCK0, 0 /SET TO 1 TO INHIBIT REWIND ON BLOCK 0 MTATAD, TAD MTA0 /USED TO MAKE HANDLER SERIALLY REUSABLE /CONTENTS MUST BE 13XX [V3C] MTISZ, ISZ MTANO /DITTO STOP, ISZ MTHX MTEXIT, HLT /CIF CDF TO USER'S FIELD JMP I MTHX PNEXT, 0 /V3C CLA TAD MTANO /GET UNIT # CIA TAD MTATAD /FIND WHICH ENTRY POINT DCA MTFUN /MAKE A 'TAD MTAN' AND EXECUTE IT MTFUN, HLT DCA MTHX /COLLECT ARGUMENTS VIA 'MTHX' CLA STL RTR /2000 TAD MTFUN /MAKE A 'DCA MTAN' AND EXECUTE IT DCA NBLOK TAD MTISZ /RESTORE DESTROYED ISZ NBLOK, HLT TAD I MTHX /GET FUNCTION WORD DCA MTFUN /SAVE IT IN 'MTFUN' ISZ MTHX /POINT TO BUFFER ADDRESS STA /GET ONE LESS THAN TAD I MTHX /BUFFER ADDRESS DCA NBUFF /AND STORE AWAY ISZ MTHX /POINT TO BLOCK NUMBER TAD I MTHX /GET BLOCK NUMBER DCA NBLOK /STORE AWAY ISZ MTHX /POINT TO ERROR RETURN RDF /GET CALLING FIELD TAD MTCDIF /CREATE CIF CDF TO USER'S FIELD DCA MTEXIT /STORE AWAY WHERE WILL BE USEFUL LATER MTCDIF, CIF CDF 0 /GO TO FIELD 0 TAD MTANO /GET UNIT NUMBER CLL RTR RTR DCA MTANO /PUT IN BITS 0-2 OF 'MTANO' TAD MTFUN /RETRIEVE FUNCTION WORD AND L70 /ISOLATE FIELD OF BUFFER TAD PARITY /SET ODD PARITY BITS, AND DENSITY 8 (800 BPI, 7-CHANNEL) TAD MTANO /COMBINE WITH UNIT NUMBER DCA MTAWD /TO GET A USEFUL MTA COMMAND TAD MTFUN /ZERO BUFFER FOR PIP ON EOF AND L70 /FIELD OF ORIGIN TAD MTCDF DCA USRCDF USRCDF, MTANO, 0 DCA MTANO /RESET 'MTANO' FOR NEXT CALL TAD MTFUN RAL AND P7600 /GET # OF WORDS IN BUFFER SNA SZL /ZERO BUFFER IF READING JMP P7600 CIA DCA MTH TAD NBUFF DCA ERROR MCLRLP, ISZ ERROR L100, 100 DCA I ERROR ISZ MTH JMP MCLRLP P7600, 7600 MTCDF, CDF 0 TAD BLOCK0 SNA /OPERATE IN MULTIPLE-FILE MODE? TAD NBLOK /RETRIEVE BLOCK SZA CLA /IS IT BLOCK 0? JMP BIGBLK /NO TAD MTATAD /YES, REWIND [CAN BE 13XX] JMS MTH /CALL MAGTAPE ROUTINE MTAWD, 1000 /CA IMMATERIAL M7603, -7603 /WC IMMATERIAL L70, 70 /NO REWIND ERRORS (THESE CAN'T OCCUR) BIGBLK, TAD MTFUN JMS I PNEXT /GO READ OR WRITE NEXT PAGE NBUFF, 0 /ONE LESS THAN ADDRESS OF BUFFER /MUST BE AT LOC AFTER CALL TO NEXT / MTH /SET UP WC AND CA REGISTERS, LOAD FUNCTION AND GO /CALLING SEQUENCE: / TAD (FNWORD / JMS MTH / BUFFER ADDRESS-1 / -WORD COUNT / MASK FOR UNACCEPTABLE ERROR CONDITIONS / <NORMAL RETURN> / TAKES HANDLER ERROR RETURN ON ERRORS. / IF ERROR, AC HAS ERROR CODE FROM MAIN STATUS REGISTER / AC IS POSITIVE IF E.O.F. READ MTH, 0 /MUST BE AT 2ND LOC AFTER CALL TO NEXT DCA ERROR /SAVE FUNCTION TEMPORARILY SKTR /V3C JMP .-1 /FIX TIMING BUG CLT /CLEAR THE WORLD TAD MTAWD LCMR /LOAD COMMAND REGISTER TAD I MTH /GET CURRENT ADDRESS LCAR /LOAD IT ISZ MTH /POINT TO WORD COUNT TAD I MTH /GET WORD COUNT (TWO'S COMPLEMENT THEREOF) LWCR /LOAD IT ISZ MTH /POINT TO ERROR MASK TAD ERROR /GET FUNCTION BACK LFGR /GO BABY GO JMS ERROR /CHECK FOR ERROR SKJD /THROUGH? JMP .-2 /NO JMS ERROR /YES, ANY ERRORS? E1, ISZ MTH /AMAZING WE MADE IT (NO ERRORS) JMP I MTH /NORMAL RETURN IFNZRO MTH-NBUFF-1 <MTHERR,XXX> ERROR, 0 TAD P7600 /YES KRS /IS IT CTRL/C? TAD M7603 /ALLOW PARITY TELETYPES SNA CLA KSF JMP SIFE CLT /ABORT I/O JMP I P7600 /RETURN TO OS/8 KEYBOARD MONITOR SIFE, SKEF /SKIP ON ERROR JMP I ERROR /RETURN, NO ERRORS RMSR /WHAT'S CAUSING THE ERROR? AND I MTH /IS IT A GOOD ONE? (USE ERROR MASK) SNA CLA /IS ERROR ACCEPTABLE? JMP E1 /YES RMSR /NOT ACCEPTABLE AND L100 /IS IT AN E.O.F.? SNA /IF SO, LEAVE BIT 0 CLEAR RMSR JMP MTEXIT /AND LEAVE WITH STATUS IN AC IFZERO .-367&4000 <PERR,ZZXX> *366 MTHX, MTAVERSION MTA7, ISZ MTANO MTA6, ISZ MTANO MTA5, ISZ MTANO MTA4, ISZ MTANO MTA3, ISZ MTANO MTA2, ISZ MTANO MTA1, ISZ MTANO MTA0, ISZ MTANO JMS PNEXT /GET ADDRESS OF FIRST LOCATION ON NEXT PAGE PAGE IFNZRO PARITY-200 <PARERR,ZZZ> *400 NEXT, 0 DCA RECNO /READ OR WRITE AND HOW MANY TAD NEXT TAD KSTOP DCA NSTOP /ADDRESS OF RETURN ROUTINES TAD NEXT TAD KBLOK DCA WC TAD I WC DCA WC TAD I NEXT DCA BUFFER /GET BUFFER ADDRESS - 1 ISZ NEXT /POINT TO MTH TAD (3677 /V3C DCA ERFLAG /DEFAULT IS REPORT ALL ERRORS EXCEPT EOF TAD RECNO CLL RAL /LINK SPECIFIES READ OR WRITE AND L7600 /-(# OF BLOCKS)^200 SNA JMP ZERO /0 PAGE COUNT! DCA RECNO SZL /READ OR WRITE? STL CLA RTR /WRITE. +2000 TO CONVERT READ CODE TO WRITE CODE TAD L2100 /READ (OR WRITE) & GO DCA TEMP /SAVE THIS COMMAND TAD L7600 DCA WC /OS/8 USES 128 WORD BLOCKS STA /V3C DCA ERFLAG /NOW DEFAULT IS REPORT ALL ERRORS RL1, TAD TEMP JMS GO TAD BUFFER /NEXT 200 WORDS TAD L200 DCA BUFFER TAD RECNO /ANY MORE? TAD L7600 SNA JMP I NSTOP /NO, FINISH DCA RECNO /YES, LOOP JMP RL1 /REJOIN PROCESSING KSTOP, STOP-NBUFF /USED TO RELOCATE 'STOP' KBLOK, NBLOK-NBUFF FLAG, 0 COUNT, TEMP, 0 EFL2, TAD L5100 JMS GO /ALL THIS CODE IS NEW FOR V3C EFL1, TAD L5100 JMP GOO /V3C GO, 0 JMS I NEXT /CALL MTH BUFFER, HLT WC, 0 ERFLAG, -1 JMP I GO L5100, 5100 RECNO, 0 NSTOP, 0 L7, 7 L2100, 2100 ZERO, TAD RECNO /RETRIEVE FN WORD (MUST PRESERVE LINK) AND L7 /ISOLATE SPECIAL CODE TAD PJUMP DCA .+1 FN, HLT /BRANCH THROUGH JUMP TABLE TABLE, JMP EFL2 /0 CLOSE. WRITE TWO EOF'S JMP REW /1 REWIND JMP SPACE /2 SPACE FORWARD/REVERSE RECORDS JMP SEOF /3 SPACE FORWARD/REVERSE FILES JMP UNLOAD /4 REWIND AND OFF-LINE JMP EFL1 /5 WRITE EOF JMP SPEC /6 READ OR WRITE WITH SPECIAL BLOCKSIZE PJUMP, JMP TABLE /7 UNUSED SAME AS 0 SEOF, RAR /LINK ON MEANS REVERSE RTR DCA FN TAD WC DCA COUNT STA DCA WC RMSR AND (3000 /CHECK BOT BIT SZA CLA /SIMULATE DATA IF AT BOT (OR REWINDING) FILE, CLA IAC FILE2, DCA FLAG TAD FN TAD L6100 /V3C FORWARD [OR BACKSPACE] A RECORD JMS GO RMSR AND P100 SNA CLA /SKIP IF FILE MARK FOUND JMP FILE TAD FN TAD FLAG SZA CLA /WAS THERE ANY DATA? JMP CONT /V3C YES, CONTINUE /EITHER SAW DATA OR WAS GOING IN REVERSE STL /NO, BACKSPACE ONE RECORD SPACE, CLA CMA /V3C DON'T TOUCH LINK DCA ERFLAG /ALL ERRORS ARE FATAL RAR /LINK ON MEANS REVERSE (READ BIT) STL RAR STL RAR UNLOAD, TAD P100 /ADD IN 'GO' BIT GOO, JMS GO JMP I NSTOP CONT, ISZ COUNT /V3C JMP FILE2 /CONTINUE? JMP I NSTOP /CHECK FOR EOD BEFORE COUNT /FLAG .NE. 0 MEANS SAW DATA L6100, 6100 P100, 100 L7600, 7600 SPEC, CLA CMA /V3C DON'T TOUCH LINK DCA ERFLAG /ALL ERRORS ARE NOW FATAL SZL /LINK STILL CONTAINS READ/WRITE BIT STL CLA RTR TAD L2100 /V3C JMP GOO /V3C REW, DCA ERFLAG /NO REWIND ERRORS TAD (1000 /V3C JMP UNLOAD /V3C L200, 200 PAGE $