COMPIL(THR,<INOUT>,<SIMIO,SAVE,RESTR,GETCHN>
	,<THROUGH I/O ROUTINE>)
HEREFK (INOUT,.INOUT)
	PUSHJ	P,SAVE		;SAVE AC'S,GET GOGTAB
	MOVE	LPSA,[XWD 6,6]
	MOVE	CHNL,-2(P)	;OUTPUT CH NUMBER
	LOADI7	A,<INOUT (OUTPUT SIDE)>
	PUSHJ	P,GETCHN
	SETZM	@ENDFL(CDB)	;CLEAR ERROR INDICATOR
	LDB	TEMP,[POINT 4,DMODE(CDB),35] ;CHECK MODE
CMU <
	MOVEI	Z,1
	CAIN	TEMP,3		;IS THE MODE 3
	 TRZA	Z,-1		; YES!!!
	CAIN	TEMP,4		;OR CMU IMAGE MODE?
	 JRST	.+4		;UGLY, BE CAREFUL OF CODE CHANGES!
>;CMU
	CAIL	TEMP,10		;MUST BE BINARY MODE
	CAILE	TEMP,14		;AND NOT DUMP MODE
	ERR	<INOUT (OUTPUT SIDE): ILLEGAL DATA MODE:>,6
	PUSH	P,CDB		;SAVE - 
	PUSH	P,CHNL		;WELL DO IT AGAIN
	MOVE	CHNL,-5(P)		;SEE...
	LOADI7	A,<INOUT (INPUT SIDE)>
	PUSHJ	P,GETCHN	;DO YOUR THING
	SETZM	@ENDFL(CDB)	;CLEAR ERROR INDICATOR
	LDB	TEMP,[POINT 4,DMODE(CDB),35]
CMU <
	MOVEI	Y,1
	CAIN	TEMP,3		;IS THE MODE 3
	 TRZA	Y,-1		;YES!!!
	CAIN	TEMP,4		;OR CMU IMAGE MODE
	 JRST	.+4		;CAREFUL OF RELATIVE JUMPS!
>;CMU
	CAIL	TEMP,10
	CAILE	TEMP,14
	ERR	<INOUT (INPUT SIDE): ILLEGAL DATA MODE:>,6
	SKIPGE	B,-3(P)		;# OF WORDS
	HRLOI	B,377777	;ARBITRARILY LARGE NUMBER OF WDS
TH1:	JUMPE	B,RESTR		;NO MORE TO DO
	SKIPG	E,ICOWNT(CDB)	;#OF WORDS IN BUFFER
	JRST	TH5		;BETTER GET SOME MORE
CMU <
	CAIN	Y,0		;IMP MODE?
	 LSH	E,-2		;DIVIDE BY 4 TO GET WORD COUNT
>;CMU
	IBP	IBP(CDB)	;MAKE SURE POINT TRIGHT
	HRL	C,IBP(CDB)	;INPUT POINTER
	EXCH	CHNL,(P)	;NOW FREEN OUTPUT STUFF
	EXCH	CDB,-1(P)
	SKIPG	OCOWNT(CDB)	;SOME LEFT
	XCT	IOOUT,SIMIO
	SKIPA
	JRST	THERR
	IBP	OBP(CDB)
	HRR	C,OBP(CDB)	;OUTPUT POINTER
	CAML	E,B		;FIND # OF WORDS
	MOVE	E,B		;TO BLIT
NOCMU <
	CAML	E,OCOWNT(CDB)	;=MIN(B,ICOWNT,OCOWNT)
	MOVE	E,OCOWNT(CDB)
>;NOCMU
CMU <
	CAMGE	E,OCOWNT(CDB)	;=MIN(B,ICOWNT,OCOWNT)
	JRST	.+4
	MOVE	E,OCOWNT(CDB)
	CAIN	Z,0		;IMP MODE?
	LSH	E,-2		;DIVIDE BYTE COUNT BY 4
>;CMU
	MOVEI	D,(C)		;MAKE BLT TERMINATOR
	ADDI	D,-1(E)		;FINAL ADDRESS
	BLT	C,(D)		;CHOMP CHOMP
	SUB	B,E		;WE'VE DONE THESE
	MOVEI	A,-1(E)		;TO UPDATE BYTE POINTER
	ADDM	A,OBP(CDB)	;TOLD YOU SO
CMU <
	CAIE	Z,0		;IMP MODE?
	 JRST	.+3
	LSH	E,2		;MULTIPLY BY 4 FOR BYTE COUNT
	DPB	Z,[POINT 6,OBP(CDB),5]
>;CMU
	SUBM	E,OCOWNT(CDB)	;UPDATE WORD COUNT
	MOVNS	OCOWNT(CDB)	;CLEVER,EH?
TH6:	EXCH	CHNL,(P)	;BACK TO INPUT SETUP
	EXCH	CDB,-1(P)
	ADDM	A,IBP(CDB)	;UPDATE INPUT PTR
CMU <
	CAIE	Y,0		;IMP MODE?
	 JRST	.+3
	LSH	E,2		;MULTIPLY BY 4 FOR BYTE COUNT
	DPB	Y,[POINT 6,IBP(CDB),5]
>;CMU
	SUBM	E,ICOWNT(CDB)	;UPDATE WORD COUNT
	MOVNS	ICOWNT(CDB)	;SUBTRACTION WAS BACKWARDS
	JRST	TH1		;MORE OF SAME
TH5:	XCT	IOIN,SIMIO	;DO SOME INPUT
	JRST	TH1		;NOW GO PLAY
THERR:	SKIPGE	TEMP,-3(P)	;# THE GUY WANTED
	HRLOI	TEMP,377777	;IT WAS A FUDGE
	SUB	TEMP,B		;SUBTRACT #LEFT TO GET
	HRRM	TEMP,@ENDFL(CDB);#HE GOT
	JRST	RESTR
ENDCOM(THR)