; SUBROUTINE TO DO MULTIPLE-PRECISION ADDS.
;	ENTRY:	(IX) = POINTS TO MOST SIGNIFICANT BYTE OF DESTINATION.
;			(IY) = POINTS TO MOST SIGNIFICANT BYTE OF SOURCE.
;			(B) = NUMBER OF BYTES IN OPERANDS.
;			CALL MULADD.
;			(RETURN).
;	EXIT:	(IX) = UNCHANGED.
;			(IY) = UNCHANGED.
;			(A) = DESTROYED.
;			(B) = 0.
;
.org	0000h

		LD	SP,	0080h	; ADDED FOR TESTING PURPOSES.
		
		LD	IX,	0050h
		LD	IY,	0060h
		LD	DE,	9999h
		LD	B,	04h
		LD	A,	00h
		
		CALL MULADD
		HALT
		
MULADD:	PUSH	DE		; SAVE DE.
		LD	E,	B		; NUMBER OF BYTES TO E.
		LD	D,	0		; DE NOW HAS NUMBER.
		DEC	DE			; DE NOW HAS NUMBER -1.
		ADD	IX,	DE		; POINT TO LEAST SIGNIFICANT BYTE.
		ADD	IY,	DE		; POINT TO LEAST SIGNIFICANT BYTE.
		POP	DE			; RESTORE ORIGINAL.
		XOR 	A		; RESET CARRY FLAG.
LOOP:	LD	A,	(IX +0)	; GET DESTINATION.
		ADC	A,	(IY +0)	; ADD SOURCE.
		LD	(IX +0), A	; STORE RESULT.
		DJNZ	LOOP1	; GO IF NOT DONE.
		RET				; RETURN.
LOOP1:	DEC	IX			; POINT TO NEXT HIGHER.
		DEC	IY			; POINT TO NEXT HIGHER.
		JP LOOP			; CONTINUE.
		

.ORG 0050h
FIFTY:	.DB	11h,22h,33h,44h
.ORG 0060h
SIXTY:	.DB 55h,0EEh,77h,0FFH

.END