--- /dev/null
+/OVRDRV - OVERLAY DRIVER FOR CCL
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+/COPYRIGHT (C) 1977,1978 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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+\f
+/OVERLAY DRIVER
+/FOR LINKER PROGRAM MODULES
+/VERSION=V3A
+
+
+/THIS SECT IS TWO LOCATIONS AND CONTAINS THE TRANSFER VECTOR TO SWAPER
+/AND A FLAG THAT INDICATES WHETHER A JMP (1) OR JMS (0) WAS PERFORMED
+/TO THE TRANSFER VECTOR
+
+/ .SECT XFERV,Z
+/ 0 /FLAG, 1=JMP, 0=JMS
+/ SWAPER /TRANSFER VECTOR TO SWAP ROUTINE
+
+/THIS IS THE MAIN DRIVER SECTION
+
+ .SECT SWAPER,R
+ .GLOBAL SWPTAB,TRANVC
+
+ .ZTERNAL XFERV
+ FIELD 1
+
+SWAP, 6102 /VERSION NUMBER
+ DCA AC /SAVE CALLING AC
+ RAL
+ DCA LINK /AND LINK
+ RDF /GET CALLING DF
+ TAD (CDF /FORM CDF
+SWAP0, JMP ONCE /DO ONCE ONLY CODE - REPLACED BY DCA EXIT
+ CDF . /CHANGE TO THIS DATA FIELD
+ TAD I SWAP /GET OVERLAY,LEVEL,FIELD
+ DCA BINDAT /SAVE
+ ISZ SWAP /BUMP POINTER
+ TAD I SWAP /GET SUBROUTINE ADDRESS
+ DCA XITLOC /SAVE
+ TAD BINDAT /FORM CDF TO CALLED SUBROUTINE
+ AND (7
+ RAL CLL
+ RTL
+ TAD (CDF
+ DCA SWAP1A /SAVE
+ TAD SWAP1A /FORM CIF TO CALLED SUBROUTINE
+ IAC
+ DCA EXIT+1 /SAVE FOR EXIT
+\f/LOAD OVERLAY OF CALLED SUBROUTINE
+
+LOAD, TAD BINDAT
+ AND (1600 /EXTRACT LEVEL OF CALLED SUBROUTINE
+ RTR CLL /5 RIGHT
+ RTR
+ RAR
+ DCA PNTR /SAVE
+ TAD PNTR
+ TAD (SWPTAB /COMPUTE ENTRY INTO SWAP TABLE
+ DCA FLD /POINTS TO FIELD OF OVERLAY
+ TAD PNTR /COMPUTE ENTRY INTO CURRENT OVERLAY TABLE
+ RTR CLL
+ TAD (CURTAB
+ DCA PNTR
+ TAD BINDAT /EXTRACT DESIRED OVERLAY NUMBER
+ AND (170
+ RTR CLL /RIGHT 3
+ RAR
+ CIA /NEGATE
+ DCA TEMP
+ TAD TEMP
+ TAD I PNTR /COMPARE WITH CURRENT OVERLAY NUMBER FOR LEVEL
+ SNA CLA /SAME?
+ JMP SWAP1 /YES, NO READING NEEDED
+LOAD1, TAD TEMP /NO, SET TO NEW
+ CIA
+ DCA I PNTR /OVERLAY NUMBER
+ TAD FLD /SET UP POINTERS TO
+ IAC
+ DCA ADDRES /ADDRESS
+ TAD ADDRES
+ IAC
+ DCA RELBLK /RELATIVE BLOCK NUMBER
+ TAD RELBLK
+ IAC
+ DCA LENGTH /LENGTH OF OVERLAY
+ TAD TEMP /TEST OVERLAY NUMBER
+ SNA CLA /0?
+ JMP LOAD2 /YES, NO MULTIPLICATION NEEDED
+ TAD I LENGTH /BLOCK NUMBER = (LENGTH OF OVERLAY)
+ JMP I .+1 /TIMES (THE NUMBER OF THE OVERLAY)
+ PATCH
+LOAD2, TAD I RELBLK /PLUS (RELATIVE BLOCK OF LEVEL)
+ TAD STRBLK /PLUS (STARTING BLOCK OF PROGRAM)
+ DCA REDBLK /SAVE IN CALL LOCATION
+ TAD I ADDRES /GET ADDRESS TO LOAD
+ DCA REDADD /SAVE IN CALL LOCATION
+ TAD I FLD /GET FIELD
+ AND (7 /MASK
+ RTR CLL
+ RAR /POSITION
+\f TAD I LENGTH /GET LENGTH
+ RTL
+ RTL
+ RTL
+ DCA REDCNT /FORM CONTROL WORD
+ CIF 0
+ JMS I (7607 /CALL SYSTEM HANDLER TO READ IN OVERLAY
+REDCNT, 7756 /FUNCTION CONTROL WORD (POINTS TO MREAD-1 FOR "ONCE"
+REDADD, -7607 /BUFFER ADDRESS (CONTAINS SYS: ENTRY POINT FOR "ONCE"
+REDBLK, 0 /STARTING BLOCK NUMBER
+ HLT /ERROR RETURN ADDRESS
+
+SWAP1, TAD XFERV /GET JMP-JMS FLAG
+ SZA CLA /SET?
+ JMP SWAP2 /YES, EXECUTE A JMP
+ CLA CLL CMA RTL /-3
+ TAD SWAP /BACK UP TO CALLER'S PC
+ DCA SWAP
+ TAD I SWAP
+SWAP1A, 0 /CDF TO CALLED SUBROUTINE
+ DCA I XITLOC /SAVE IN CALLED SUBROUTINE
+ ISZ XITLOC /BUMP TRANSFER ADDRESS
+ CDF .
+ TAD (ISZ XFERV
+ DCA I SWAP /SET BACK UP ENTRY IN XFER VECTOR TABLE
+SWAP2, DCA XFERV /CLEAR FLAG
+ TAD LINK /RESTORE LINK AND AC
+ RAR CLL
+ TAD AC
+EXIT, 0 /SET DF TO CALLING FIELD
+ 0 /SET IF TO CALLED FIELD
+ JMP I XITLOC /GO TO CALLED SUBROUTINE
+
+\f/VARIABLE LOCATIONS
+/SOME OF THE FOLLOWING LOCATIONS CONTAIN
+/ONCE ONLY CODE TO SET UP STARTING BLOCK
+/AND CHECK THAT FILE CAME FROM SYS:
+CURTAB=. /CURRENT OVERLAY IN LEVEL TABLE (8 ENTRIES)
+STRBLK=. /ENTRY 0 IS USED TO HOLD STARTING BLOCK OF FILE
+ONCE, DCA EXIT /SAVE CALLING FIELD
+ /ALSO ENTRY 0
+ TAD .-1 /SET UP SO WON'T BE EXECUTED AGAIN
+ /ALSO ENTRY 1
+ DCA SWAP0
+ /ALSO ENTRY 2
+ CDF 0
+ /ALSO ENTRY 3
+ TAD I FLD /GET STARTING BLOCK FROM "SOFSET"
+ /ALSO ENTRY 4
+ SNA
+ /ALSO ENTRY 5
+ HLT /ERROR, K.M. PATCHES NOT IN
+ /ALSO ENTRY 6
+ DCA STRBLK /SAVE
+ /ALSO ENTRY 7
+ TAD I REDCNT /CHECK FILE CAME FROM SYS:
+ TAD REDADD
+
+BINDAT, /CONTAINS OVERLAY,LEVEL,FIELD OF DESIRED SUBROUTINE
+ SNA CLA /FROM SYS: ?
+XITLOC, /CONTAINS LOCATION TO GO TO IN DESIRED SUBROUTINE
+ JMP SWAP0+1 /YES, OK
+PNTR, /POINTS INTO CURTAB
+ HLT /NO, ERROR
+TEMP, /TEMP STORAGE
+ JMP .-1 /DON'T ALLOW CONTINUE
+FLD, /POINTS TO FIELD WORD IN SWPTAB
+ 7747 /POINTER TO "SOFSET"
+
+ADDRES=REDADD /POINTS TO ADDRESS WORD IN SWPTAB
+RELBLK=REDBLK /POINTS TO RELATIVE BLOCK WORD IN SWPTAB
+LENGTH=REDCNT /POINTS TO LENGTH WORD IN SWPTAB
+
+AC, 0 /SAVED AC
+LINK, 0 /SAVED LINK
+
+ PAGE
+\f
+/PATCH TO FIX BLOCK POSITION CALCULATION
+PATCH, IAC /CONVERT PAGES TO BLOCKS
+ CLL RAR
+ DCA PTEMP
+ TAD PTEMP /MULTIPLY BLOCK LENGTH
+ ISZ I PPNT /BY OVERLAY NUMBER
+ JMP .-2
+ JMP I .+1
+ LOAD2
+PPNT, TEMP
+PTEMP, 0
+
+
+
+/THIS AREA CONTAINS OVERLAY DATA FOR MAIN AND THE 7 LEVELS
+/THE FORMAT OF EACH ENTRY IS:
+/WORD1: FIELD OF LEVEL
+/WORD2: ADDRESS OF LEVEL
+/WORD3: RELATIVE BLOCK OF 1ST OVERLAY IN LEVEL
+/WORD4: LENGTH OF THE LEVEL (ANY AND ALL OVERLAYS-EACH)
+/ (ALL OVERLAYS IN A LEVEL ARE THE SAME LENGTH)
+
+SWPTAB,
+
+ *.+40
+
+/THIS AREA CONTAINS THE TRANSFER VECTORS FOR EACH ENTRY POINT
+/IN ALL THE OVERLAYS IN ALL THE LEVELS
+/ITS SIZE SHOULD BE MODIFIED BY THE USER
+/TO FIT THE MAXIMUM NUMBER OF TRANSFER VECTORS NEEDED
+/EACH TRANSFER VECTOR OCCUPIES 4 LOCATIONS
+/THE TABLE IS INITIALLY SET UP FOR 24(DEC) (30(OCT)) VECTORS
+/THE MAXIMUM SIZE THIS TABLE CAN BE IS 3774 (OCT) LOCATIONS FOR
+/511 (DEC) (777 (OCT)) VECTORS
+/THE FORMAT OF EACH VECTOR ENTRY IS:
+/WORD1: ISZ XFERV
+/WORD2: JMS I XFERV+1
+/WORD3: LEVEL/OVERLAY/FIELD
+/WORD4: ADDRESS
+
+TRANVC,
+
+ SIZE=53. /MODIFY THIS LINE TO CHANGE THE SIZE OF THE TABLE
+ /SET FOR 24(DEC)
+
+ *SIZE^4+.
+
+
+\f
projects / pdp8.git / blobdiff