--- /dev/null
+/4 TD8E HANDLER FOR BUILD..TD8E-A
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+/COPYRIGHT (C) 1974,1975,1977 BY DIGITAL EQUIPMENT CORPORATION
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+/
+/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.
+/
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+/
+ *0
+ -2
+DEVICE TD8A;DEVICE DTA0;4210;4010;ZBLOCK 2
+DEVICE TD8A;DEVICE DTA1;4210;4014;ZBLOCK 2
+
+ SDSS=6771 /SKIP ON SINGLE LINE FLAG
+ SDST=6772 /SKIP ON TIME ERROR
+ SDSQ=6773 /SKIP ON QUAD LINE FLAG
+ SDLC=6774 /LOAD TAPE COMMAND REGISTER
+ SDLD=6775 /LOAD DATA REGISTER
+ SDRC=6776 /READ COMMAND REGISTER
+ SDRD=6777 /READ DATA REGISTER
+
+ TDVERSION="D&77
+
+/V3 CHANGES:
+
+/1. VERSION # IS NOW 1
+/2. PARITY ^C IS NOW LEGAL
+/3. ^C CHECK NO LONGER WILL ADVANCE READER
+
+/MAINTENANCE RELEASE CHANGES:
+
+/4. FIXED ^C BUG
+/5. MADE CODE IMPROVEMENTS
+/6. FIXED RETRY BUG
+
+
+ *200
+
+NXINIT, 7600 /CLEAR AC HERE!!!
+ JMS I CINIT2 /PART OF INITIALIZATION..DO THE PART
+BASE2, DCA JINIT /ON SECOND PAGE AND THEN TO JINIT
+ JMP JINIT
+
+BUFF, 0
+PGCT, 0
+FUNCT, 0
+C1000, 1000
+
+DTA0, TDVERSION /ENTRY FOR UNIT 0
+ CLA CLL
+ JMP DTA1X
+UNIT, 0 /FILLER WORD
+DTA1, TDVERSION /ENTRY FOR UNIT 1
+ CLA CLL CML
+ TAD DTA1
+ DCA DTA0 /PICK UP ARGS AT DTA0
+DTA1X, RAR
+ DCA UNIT /UNIT # FROM LINK
+ RDF
+ TAD C6203
+ DCA LEAVE /SET UP EXIT FROM HANDLER
+ TAD I DTA0
+ DCA FUNCT /SAVE FUNCTION WORD
+ TAD FUNCT
+ CLL RAL
+C200, AND CM200 /GET A PAGE COUNT
+ DCA PGCT
+ TAD FUNCT
+C374, AND C70 /ISOLATE FIELD OF TRANSFER
+ TAD C6203
+ DCA XFIELD
+ ISZ DTA0 /POINT TO BUFFER
+ TAD I DTA0
+ DCA BUFF
+ ISZ DTA0 /POINT TO RECORD
+ TAD I DTA0
+ CLL RAL /CONVERT TO DECTAPE BLOCKS
+ DCA TBLOCK
+ ISZ DTA0 /POINT TO ERROR RET.
+C6203, CIF CDF 0
+\f
+JINIT, JMP INIT /FIRST TIME THRU IT GETS EXECUTED
+ /THE RETURN FROM INIT ZEROES IT
+ CLA CLL CMA RTL
+ DCA ERCNT /3 ERROR TRIES
+ TAD UNIT
+ DCA I CXUNIT
+ JMS I CSELCT /CHECK FOR SELEC ERROR
+ JMP .-1 /LOOPS IF NO ^C AND SELECT ERROR
+ TAD FUNCT
+ CLL RAR
+ JMP GO /OK.. START THE SEARCH
+TRWCOM, SDST /TIME OR CHECK SUM ERROR?
+ SZA CLA
+ JMP TRY3 /YES TRY UP TO 3 TIMES
+ TAD PGCT /NO.. IS PAGE COUNT EXHAUSTED?
+ TAD CM200
+ SNA
+ JMP EXIT /YES.. DONE THIS TRANSFER
+ DCA PGCT /NEW PAGE COUNT
+ ISZ TBLOCK
+ TAD BUFF
+ TAD C200 /GET NEW BUFFER ADDRESS
+ DCA BUFF
+ CLL CML /FORCE FORWARD MOTION
+GO, CLA CML RTR /PUT IN DIRECTION BIT
+ TAD C1000
+ TAD UNIT
+ SDLC /INITIATE THE MOTION
+ JMS I CRDQAD /WAIT FOR 8 LINES TO PASS
+ JMS I CRDQAD
+M20, 7760 /DON'T CARE IF IT DOES SKIP!!!
+TSRCH, SDSS /WAIT\ f FOR BLOCK MARK OR END ZONE
+ JMP .-1
+ SDRC
+ CLL RTL /DIRECTION TO LINK, DATA TO AC 4-9
+ AND C374 /ISOLATE M.T BITS
+ TAD M110 /IS IT END ZONE?
+ SNA
+ JMP ENDZ /YES..DO SOMETHING REASONABLE
+ TAD M20 /HOW ABOUT BLOCK MARK?
+ SZA CLA
+ JMP TSRCH /NEITHER..KEEP LOOKING
+ SDRD /WHAT IS THIS BLOCK'S #?
+ SZL /IF IN REVERSE, LOOK FOR 3 BEFORE
+ TAD TC3 /THE ACTUAL TARGET BLOCK
+ CMA
+ TAD TBLOCK
+ CMA
+ SNA /IS THIS THE BLOCK?
+ JMP TFOUND /YES..HAVE CORRECT ONE
+M110, SZL SNA CLA /ARE WE HEADED PROPERLY?
+ JMP TSRCH /YES.. KEEP LOOKING
+ENDZ, SDRC /IF WE ARE IN END ZONE FORWARD, WE LOSE
+ CLL RTL
+ JMP GO /EXECUTE TURN AROUND AND SEARCH
+\fTRY3, CLA CLL /V3C
+ ISZ ERCNT /TRIED 3 TIMES?
+ JMP GO
+ JMP FATAL
+EXIT, ISZ DTA0 /NORMAL RETURN
+ CLL CML
+FATAL, TAD UNIT /STOP TAPE FIRST
+ SDLC
+ CLA CML RAR /EITHER 0 OR 4000 IN AC
+LEAVE, HLT /GETS CIF CDF N
+ JMP I DTA0
+
+INIT, JMS . /FIND OUT WHERE WE GOT LOADED
+BASE, TAD CRDQAD
+ SPA /NEGATIVE ENDS LIST
+ JMP NXINIT
+ TAD INIT
+ DCA CRDQAD
+ ISZ .-1
+ ISZ BASE
+ JMP BASE
+
+CRDQAD, R4LINE-BASE
+CINIT2, INIT2-BASE
+CSELCT, SELECT-BASE
+CXUNIT, XUNIT-BASE
+
+ *367
+TFOUND, SZL CLA /ARE WE IN RIGHT DIRECTION
+ JMP GO /NOT YET
+ TAD FUNCT
+ CLL RAL /R/W TO LINK
+ CLA
+C70, 70
+TC3, 3
+ TAD BUFF
+XFIELD, HLT /CONTROL 'TRICKLES THROUGH
+
+TBLOCK=DTA1
+ERCNT=INIT+1
+CM200=NXINIT
+DTA2=DTA0
+DTA3=DTA1
+DTA4=DTA0
+DTA5=DTA1
+DTA6=DTA0
+DTA7=DTA1
+\f *400
+ CIF 0 /WE ARE IN FIELD 0
+ DCA XBUFF
+ RAR
+ DCA XFUNCT /READ/WRITE TO FUNCTION
+RGRD, SDSS
+ JMP .-1 /LOOK FOR REVERSE GUARD PATTERN
+ SDRC
+ AND K77
+ TAD CM32
+ SZA CLA /IF NOT REV. GUARD, KEEP LOOKING
+ JMP RGRD
+ TAD C7600
+ DCA WORDS /128 WORDS/BLOCK
+ TAD XFUNCT
+K7700, SMA CLA /IS IT READ OR WRITE?
+ JMP TREAD
+ SDRC /CHECK FOR WRITE LOCKOUT
+ AND TC300
+ CLL /SETUP TO RETRY IF WRITE LOCK
+ SZA CLA
+ JMP I CTRY3 /IF LOCKED OUT, ERROR
+ JMS R4LINE /SKIP A WORD
+C7600, 7600 /CLA
+ TAD C1400
+ TAD XUNIT
+ SDLC /TURN ON WRITE HEAD
+ CLA CMA
+ JMS W4LINE /7777 IN REV. CHECKSUM
+ CLA CMA
+ DCA CSUM /AND ALSO TAPE CHECKSUM
+WRTLP, TAD I XBUFF
+ JMS W4LINE
+ ISZ XBUFF /INCREMENT BUFF. ADD.
+K77, 77
+ ISZ WORDS /DONE A BLOCK?
+ JMP WRTLP
+ JMS W4LINE /A 129 TH WORD OF 0
+ JMS GCHK /GET 6 BIT CHECKSUM
+ JMS W4LINE /WRITE IT TO TAPE
+ JMS W4LINE /LET CHECK SUM FINISH
+ JMP I CRWCOM /SEE IF WE ARE FINISHED
+\f
+TREAD, JMS R4LINE
+ JMS R4LINE /SKIP CONTROL WORDS
+ JMS R4LINE
+ AND K77 /CHECKSUM
+ TAD K7700
+ DCA CSUM
+RDLP, JMS R4LINE
+ JMS EFUN /ADD WORD TO CHECKSUM
+ DCA I XBUFF
+ ISZ XBUFF
+TC300, 300
+ ISZ WORDS /DONE BLOCK?
+ JMP RDLP
+ JMS R4LINE
+ JMS EFUN /CHECK SUM 129 TH WORD
+ JMS R4LINE
+ AND K7700 /READ CHECKSUM
+ JMS EFUN
+ JMS GCHK /COMPARE TAPE AND OUR CHECKSUM
+ JMP I CRWCOM
+
+W4LINE, 0 /ADD TO CHECKSUM AND WRITE A 12 BIT
+ JMS EFUN /WORD
+ SDSQ
+ JMP .-1 /SKIP ON QUAD LINE FLAG
+ SDLD
+ CLA /AC IS NOT CLEARED AFTER SDLD
+ JMP I W4LINE
+
+R4LINE, 0 /WAIT FOR QUAD FLAG AND READ
+ SDSQ
+ JMP .-1
+ SDRD
+ JMP I R4LINE
+
+EFUN, 0 /COMPUTE EQUIVALENCE CHECKSUM
+ CMA
+ DCA ETMP /ACTUALLY CHECKSUMS ON DECTAPE ARE
+ TAD ETMP /EQUIVALENCE OF ALL WORDS IN A RCORD
+ AND CSUM /6 BITS AT A TIME. SINCE EQUIVALENCE
+ CIA /IS ASSOCIATIVE WE DO IT 12 AT A TIME
+ CLL RAL /AND CONDENSE LATER.
+ TAD ETMP /IDENTITIES USED ARE:
+ TAD CSUM /A+B=(A.XOR.B)+2*(A.AND.B)
+ DCA CSUM /A.EQU.B=.NOT.(A.XOR.B)=A.XOR.(.NOT.B)
+ TAD ETMP /A.EQU.B=(A+(.NOT.B))-2*(A.AND.(.NOT.B))
+ CMA
+ JMP I EFUN
+
+\fGCHK, 0 /FORM 6 BIT CHECKSUM
+ CLA
+ TAD CSUM
+ CLL CMA RTL
+ RTL
+ RTL
+ JMS EFUN
+ CLA CLL CML
+ TAD CSUM
+ AND K7700
+ JMP I GCHK
+
+INIT2, 0 /TIS INITIALIZES LOCS IN PAGE 2
+INIT3, TAD CTRY3
+ SNA
+ JMP I INIT2 /0 ENDS LIST
+ TAD INIT2
+ DCA CTRY3 /UPDATE THE LIST
+ ISZ .-1
+ ISZ INIT3
+ JMP INIT3
+
+CTRY3, TRY3-BASE2
+CRWCOM, TRWCOM-BASE2
+XBUFF, 0 /0 MUST TERMINATE IT!!
+CM32, -32
+C1400, 1400
+
+SELECT, 0 /THIS ROUTINE CHECKS FOR SELECT
+ TAD XUNIT /AND ^C TYPED
+ SDLC
+ SDRC /GET STATUS AND SEE IF SELECT ERROR ON
+ AND C100
+ SNA CLA
+ ISZ SELECT /NOPE .TAKE NORMAL OUT
+ KSF /SEE IF FLAG IS UP
+ JMP I SELECT /NO..EXIT
+ TAD C7600
+ KRS
+ TAD (-7603 /IS IT A ^C?
+ SZA CLA
+ JMP I SELECT /NO..EXIT
+ JMP I C7600
+
+C100, 100
+
+XFUNCT=INIT2
+CSUM=XFUNCT+1
+WORDS=CSUM+1
+ETMP=WORDS+1
+XUNIT=ETMP+1
+$$$$$$$
+\f
projects / pdp8.git / blobdiff