; MODFD.MAC -- MODIFY FDB FOR 0 BLOCK PRINT FILES
; AUTHOR:  J. LEONARD
; DATE WRITTEN:  03-NOV-77
;
	.NLIST	TOC		;TBL OF CONTENTS NOT WANTED
;
	.TITLE	MODFD
	.SBTTL	MODIFY FDB
;
	.ENABL	AMA		
;
	.MCALL	FDOF$L
;
	.GLOBL	$FCHNL,NAM$	
	.GLOBL	$OTSV		;OTS IMPURE PTR ADDR
	FDOF$L
;
;
; CALL:
;     CALL MODFD (LUN, NBLKS)
; WHERE:
;	LUN	= FILE'S LOGICAL UNIT
;	NBLKS	= NUMBER OF BLOCKS ALLOCATED (FROM DIR/FU)
;
D.FDB	=	14		;OFFSET TO FDB FROM FFDB
;
FBY	=	0		;FIRST FREE BYTE IN LAST BLOCK
;
MODFD::
	MOV	#MODFDN,R0	;NAME TO TRACE BK
	MOV	(R0)+,R4
	MOV	(R0)+,-(SP)	
	JSR	R4,NAM$		;TRACEBACK CHAIN
	TST	(R5)+		
	MOV	@(R5)+,R2	;GET LUN
	MOV	@#$OTSV,R3	;OTS IMPURE ADDR
	JSR	PC,$FCHNL	;GET DEVT ENTRY ADDR
	ADD	#D.FDB,R0	;LUN'S FDB ADDR
;
	MOV	@(R5)+,R1	;GET # BLOCKS
	MOV	R1,F.HIBK+2(R0)	;HIGHEST VIRTUAL BLOCK NO.
;
	ADD	#1,R1		;EOF BLOCK NO.IS F.HIBK+1
	MOV	R1,F.EFBK+2(R0)	;EOF BLOCK NO.
;
	MOV	#FBY,F.FFBY(R0)	;FIRST BYTE IN LAST BLOCK
;
	RTS	PC		;RETURN TO CALLER
;
MODFDN:	.RAD50	/MODFD /	;TRACE NAME
;
	.END