; SUBROUTINE TO MOVE MEMORY
;	ENTRY:	(HL) = SOURCE START.
;			(DE) = DESTINATION START.
;			(BC) = NUMBER OF BYTES TO MOVE.
;	EXIT:	(HL) = SOURCE AREA +1.
;			(DE) = DESTINATION AREA + 1.
;			(BC) = 0.
;
.org	0000h

		LD	SP,	0080h	; ADDED FOR TESTING PURPOSES.
		
		LD	HL,	50h
		LD	DE,	60h
		LD	BC,	10
		LD	A,	00h
		
		CALL MOVE
		HALT
		
MOVE:	PUSH	HL		; SAVE SOURCE POINTER.
		OR	A			; CLEAR CARRY.
		SBC	HL,	DE		; SOURCE - DESTINATION POINTERS.
		POP	HL			; RESTORE POINTER.
		JP	C,	MOV10	; GO IF MOVE BACK.
		LDIR			; MOVE FORWARD.
		JR	MOV20		; GO TO RETURN.
MOV10:	ADD	HL,	BC		; POINT TO END +1.
		DEC	HL			; POINT TO END.
		EX	DE,	HL		; SWAP.
		ADD	HL,	BC		; POINT TO END +1.
		DEC	HL			; POINT TO END.
		EX	DE,	HL		; SWAP BACK.
		LDDR			; MOVE BACK
MOV20:	RET				; RETURN

.ORG 0050h
FIFTY:	.DB	00h,01h,02h,03h,04h,05h,06h,07h,08h,09h,0Ah

.END