/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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/

/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
/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	PNT