;+
; MOVE -- THIS ROUTINE PERFORMS A DATA TRANSFER BETWEEN THE WRITER'S
;	  BUFFER AND THE READER'S BUFFER.
;
; INPUTS:
;	R1	READER'S I/O PACKET ADDRESS
;	R3	WRITER'S I/O PACKET ADDRESS
;	R4	WRITER'S UCB ADDRESS
;	R5	READER'S UCB ADDRESS
;
; OUTPUTS:
;	R5	CORRECT UCB FOR NEXT OPERATION
;	BOTH I/O OPERATIONS ARE TERMINATED, UNLESS THE READER HAD AN
;	ILLEGAL BUFFER CHECK (LESS THAN 3 BYTES REQUESTED)
;
;-
MOVE:	CMP	U.CNT(R5),#3	; READ REQUEST LONG ENOUGH?
	BGE	85$		; YES
	MOV	#IE.BAD&377,R0	; SET BAD PARAMETERS CODE
	CALLR	$IOALT		; FINISH I/O, NO BYTES TRANSFERRED
85$:	MOV	U.UNIT(R4),-(SP) ; PUT WRITER'S UNIT NUMBER ON STACK
	CALL	$PTBYT		; PUT IT INTO READER'S BUFFER
	DEC	U.CNT(R5)	; UPDATE READER'S BYTE COUNT
	MOV	I.PRM+6(R3),-(SP) ; PUT CARRIAGE CONTROL BYTE ON STACK
	CALL	$PTBYT		; PUT IT INTO READER'S BUFFER
	DEC	U.CNT(R5)	; AND UPDATE THE COUNT
15$:	MOV	R4,R5		; GET WRITER'S UCB ADDRESS IN R5
	CALL	$GTBYT		; GET A BYTE FROM THE WRITER'S BUFFER
	MOV	I.UCB(R1),R5	; GET READER'S UCB ADDRESS
	CALL	$PTBYT		; AND PUT THE BYTE IN READER'S BUFFER
	DEC	U.CNT(R4)	; UPDATE WRITER'S BYTE COUNT
	BNE	16$		; IF NE THEN WE'RE NOT AT THE END
	DEC	U.CNT(R5)	; AT THE END OF WRITER'S BUFFER; DON'T FORGET
				; THAT WE PUT THE BYTE IN READER'S BUFFER
	BR	17$		; FINISH BOTH I/O OPERATIONS
16$:	DEC	U.CNT(R5)	; UPDATE READER'S BYTE COUNT
	BNE	15$		; IF NE WE CAN DO MORE
17$:	MOV	I.PRM+4(R1),R1	; GET READER'S ORIGINAL BYTE COUNT
				; (R1 IS READER'S I/O PACKET ADDRESS)
	MOV	R3,-(SP)	; SAVE WRITER'S I/O PACKET ADDRESS
	MOV	R4,-(SP)	; SAVE WRITER'S UCB ADDRESS ON STACK
	MOV	#IS.CR,R0	; FINAL STATUS IS <CR> AS TERMINATOR, ALL OK.
	CALL	DONE		; FINISH I/O OPERATION
	MOV	(SP)+,R5	; RESTORE WRITER'S UCB ADDRESS TO R5
	MOV	(SP)+,R3	; RESTORE WRITER'S I/O PACKET ADDRESS
	MOV	I.PRM+4(R3),R1	; GET WRITER'S ORIGINAL BYTE COUNT
	MOV	#IS.SUC&377,R0	; WRITE SUCCESSFUL
				; FALL THROUGH TO FINISH I/O

DONE:	SUB	U.CNT(R5),R1	; SUBTRACT THOSE BYTES NOT TRANSFERRED
	CALLR	$IODON		; FINISH THE OPERATION