.TITLE	PLTAST
	.ENABL	LC
;
;	CALL PLTATA -- This subroutine attaches the plotting terminal
;	with an AST service routine.  It's purpose is to trap
;	unsolicited input.  A CNTRL/C will terminate the program execution.
;
;	CALL PLTDET -- This subroutine removes the attachment of the
;	plotting terminal.
;
	.PSECT	PLTAST
	.MCALL QIOW$S, ASTX$S
				;
PLTATA::TST	ILUN		;VALID PLOTTING DEVICE?
	BEQ	DONE		;BRANCH IF NOT
	QIOW$S	#IO.ATA,ILUN,#1,,,,<#PLTAST>	;ATTACH WITH AST
DONE:	RTS	PC		;RETURN
				;
PLTDET::TST	ILUN		;VALID PLOTTING DEVICE?
	BEQ	NOPE		;BRANCH IF NOT
	QIOW$S	#IO.DET,ILUN,#1	;REMOVE ATTACHMENT
NOPE:	RTS	PC		;RETURN
				;
PLTAST:	CMP	#3,(SP)+	;^CNTRL/C?
	BNE	CONT		;BRANCH IF NOT
	MOV	#RESET,-(SP)
	JSR	PC,STOP$
CONT:	QIOW$S	#IO.WLB,ILUN,#1,,,,<#STRING,NCHRS>
	ASTX$S			;RETURN FROM AST
RESET:	.ASCIZ	<33>/!9/<33>/;/
	.EVEN
STRING:	.ASCII	/DAVE IS A FINK./
	.EVEN
NCHRS:	.WORD	NCHRS-STRING