COMPIL(SIM,<SIMIO,CSERR,LPRYER>,<GOGTAB>
	  ,<SIMIO, CSERR, LPRYER -- SUPPORT ROUTINES>)
↑↑SIMIO:	PUSHJ	P,.+1		;SAVE PC OF XCT
	PUSH	P,C		;SAVE C
	MOVE	C,-1(P)		;ASSUME SKIP RETURN
	LDB	C,[POINT 4,-1(C),12] ;INDEX OF XCT
	JUMPE	C,USTST		;WANT STATUS BITS ONLY
	CAIL	C,13		;NOW SPLIT HIGH AND LOW INDICES
	 JRST	 ALTIO		;SKIP RETURN CHECK ONLY
EXPO <
	CAIN	C,IOIN	;
	JRST	ISIOU	;
	CAIE	C,IOOUT	;IN OR OUT ?
	JRST	NOTIOU	;NOPE
ISIOU:	SKIPG	@USBTST(C)	;CHECK FOR NO BUFFERS (& MORE AT CMU)
	JRST	USFUNY		;NO BUFFERS, ETC.
>;EXPO
NOTIOU:MOVE	C,IOINST(C)	;GET INSTRUCTION
	DPB	CHNL,[POINT 4,C,12]	;CHANNEL NUMBER
	XCT	C		;DO OPERATION
	 JRST	 USOUT		;ALL KOSHER, NO EOF OR ERR
USTST:	MOVE	C,[GETSTS C]	;WHA-
	DPB	CHNL,[POINT 4,C,12] ; T HAPPEN-
	XCT	C		;	  ED?
	MOVEM	C,FSTATS(USER)
CMU <
USERF:
>;CMU
	TRZ	C,10000		;IOACT BIT, USER LOOKUP CHECK BIT
	HRLZM	C,@ENDFL(CDB)	;GIVE USER THE BITS
	TDNN	C,ERRTST(CDB)	;ANY HE CAN'T HANDLE?
	JUMPA	CHNL,USSKIP	;NOPE, JUST SKIP-RETURN
	ERR	<I-O DEVICE ERROR ON CHANNEL >,7 ;JUMPA TO PROVIDE CHANNEL AC
USSKIP:	AOS	-1(P)		;SKIP-RETURN
USOUT:	POP	P,C		;RESTORE C
	POPJ	P,		;DONE
ALTIO:	MOVE	C,IOINST(C)	;GET INSTR
	DPB	CHNL,[POINT 4,C,12]
	XCT	C		;DO IT
	JRST	USOUT		;NO SKIP
	JRST	USSKIP		;SKIP
EXPO <
USFUNY:	
CMU <	SKIPE	@USBTST(C)	;FUNNY DEVICE?
	JRST	REALTM		; YES.
>;CMU
	JUMP	CHNL,		;FOR THE ERR MSG
	ERR	<NO BUFFERS ASSIGNED FOR I-O CHAN >,7
	JRST	USSKIP
CMU,<	COMMENT ⊗	THIS NONSENSE IS A SPECIAL MODE FOR
	THE CMU SPEECH DEVICES.  ESSENTIALLY, IT DOES EVERTHING
	AS NORMAL, EXCEPT THAT IT PICKS UP THE TIMING ERR AND
	RUN-OUT-OF BUFFERS BIT OF THE
	I/O  STATUS FROM THE STATUS WORD IN THE BUFFER HEADER,
	INSTEAD OF USING THE BIT FROM THE GETSTS.	⊗
TIMERR←←100000		;TIMING ERR BIT FOR SPEECH DEVICES
ROBERR←←200000		;RUN-OUT-OF-BUFFER ERR
REALTM:	PUSH	P,D		;NEED ANOTHER AC
	CAIE	C,IOIN		;INPUTTING?
	JRST	REALOT		; NO
	MOVSI	C,(<IN>)
	DPB	CHNL,[POINT 4,C,12]	;CHAN #
	XCT	C			;DO THE INPUT
	JRST	REALOK			;NO ERR, SO FAR
	MOVE	C,[GETSTS C]	
	DPB	CHNL,[POINT 4,C,12]	;LOOKS FAMILIAR
	XCT	C
	TRZA	C,TIMERR!ROBERR		;TURN OFF THE ONES FROM THE GETSTS
REALOK:	MOVEI	C,0
	HRRZ	D,IBPNT(CDB)		;ADDRESS OF THE NEW BUFFER
	IOR	C,-1(D)			;THE BITS FROM THE BUFFER
REALRT:	POP	P,D			;RESTORE THE AC
	TRNN	C,760000		;ERR OR EOF?
	JRST	USOUT			; NO
	JRST	USERF			; YES, GO LOOK AT IT
REALOT:	MOVE	C,[GETSTS C]
	DPB	CHNL,[POINT 4,C,12]
	XCT	C
	TRNN	C,ROBERR		;STOPPED FOR A ROB?
	JRST	REAL5			; NO
	HRRI	D,(C)			;GET THE BITS
	TRZ	D,760000		;TURN OFF THE ERRS
	HRLI	D,(<SETSTS>)
	DPB	CHNL,[POINT 4,D,12]
	XCT	D
REAL5:	MOVSI	D,(<OUT>)
	DPB	CHNL,[POINT 4,D,12]
	XCT	D
	JRST	REALRT
	JRST	REALRT			;IGNORE NOW, CATCH THE NEXT TIME THRU
>;CMU
USBTST←.-1
	XWD	CDB,IBUF	;1
	777777
	XWD	CDB,OBUF	;3
>;EXPO
IOINST←.-1		;IOSTATUS ←← 0  GET STATUS
	IN		;IOIN     ←← 1  BUFFERED INPUT
	IN D		;IODIN	  ←← 2  DUMP MODE INPUT
	OUT		;IOOUT	  ←← 3  BUFFERED OUTPUT
	OUT D		;IODOUT	  ←← 4  DUMP MODE OUTPUT
	CLOSE (D)	;IOCLOSE  ←← 5  CLOSE I,O, OR BOTH
	RELEASE	(D)	;IORELEASE←← 6
	INBUF (A)	;IOINBUF  ←← 7
	OUTBUF (A)	;IOOUTBUF ←←10
	USETI (A)	;IOSETI	  ←←11
	USETO (A)	;IOSETO	  ←←12
	SETSTS  (A)	; SET IO STATUS
	OPEN DMODE(CDB)	  ;IOOPEN	  ←←14
	LOOKUP FNAME(USER);IOLOOKUP←←15
	ENTER FNAME(USER);IOENTER  ←←16
	RENAME FNAME(USER);IORENAME←←17
HERE(CSERR)	MOVE	USER,GOGTAB
	POP	P,UUO1(USER)	;STANDARD PLACE
	ERR	<CASE INDEX OVERFLOW, VALUE IS >,13
	JRST	@UUO1(USER)	;RETURN OK
HERE (LPRYER) ERR	<DATUM OF ARRAY NOT THERE>,1
	POPJ	P,
ENDCOM(SAV)