_open		pshs	a,b,x,y
			ldd		argc,u
			cmpd	#0
			beq		@empty
			ldx		args,u		; file name
			lda		#READ.
			os9		I$Open
			bcs		@error
			sta		<filepath
			clra
			puls	a,b,x,y,pc
@error		lbsr	_abort
@empty		comb
			puls	a,b,x,y,pc





_close		pshs	a,b,x,y
			lda		<filepath
			beq		@end
			os9		I$Close
			clr		<filepath
@end		puls	a,b,x,y,pc





_read		pshs	a,b,x,y
			ldx		#$100		; store on 0x100 of TPA
@read		lda		<filepath
			ldb		#SS.EOF
			os9		I$GetStt
			bcs		@eof
			ldy		#$100
			os9		I$Read
			lbcs	@error
			cmpy	#0				; read until EOF
			beq		@eof
			tfr		y,d
			leax	d,x
			cmpx	<himem			; check memory overflow
			bcc		@outmem
			bra		@read
@eof		puls	a,b,x,y,pc
@outmem		ldb		#E$MemFul
@error		lbsr	_abort
			puls	a,b,x,y,pc

_clrfcb		exg		x,y
			clr		,x+
			ldd		#$2020
			std		,x++
			std		,x++
			std		,x++
			std		,x++
			std		,x++
			sta		,x+
			ldd		#0
			std		,x++
			std		,x++
			exg		x,y
			rts