--- /dev/null
+/16 TM8-E MAGTAPE HANDLER FOR OS/8
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+/COPYRIGHT (C) 1973,1974,1975 BY DIGITAL EQUIPMENT CORPORATION
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+/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.
+/
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+/
+\f 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="F&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
+\f
+/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
+\f *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
+\f/ 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>
+\fERROR, 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>
+\f *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>
+\f *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
+\fFLAG, 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
+\fZERO, 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
+\fL6100, 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
+ $
+\f\v
projects / pdp8.git / blobdiff