;This program adds the following two multiword numbers and saves the result: 
;DATA1 = 548FB9963CE7H and DATA2 = 3FCD4FA23B8DH.

   TITLE     	PROG3-2  (EXE)   MULTIWORD ADDITION
   PAGE 	60,132
   .MODEL SMALL
   .STACK 64
   ;--------------
   		.DATA
   DATA1     	DQ        	548FB9963CE7H
             	ORG      	0010H
   DATA2   	DQ        	3FCD4FA23B8DH
                ORG             0020H
   DATA3  	DQ        	?
   ;--------------
   		.CODE
   MAIN      	PROC  	FAR
             	MOV  	AX,@DATA
             	MOV  	DS,AX
                CLC                        ;clear carry before first addition
                MOV     SI,OFFSET DATA1    ;SI is pointer for operand1         
                MOV     DI,OFFSET DATA2    ;DI is pointer for operand2         
                MOV     BX,OFFSET DATA3    ;BX is pointer for the sum         
                MOV     CX,04              ;CX is the loop counter
   BACK:        MOV     AX,[SI]            ;move the first operand to AX  
                ADC     AX,[DI]            ;add the second operand to AX 
                MOV     [BX],AX            ;store the sum    
                INC     SI                 ;point to next word of operand1
             	INC  	SI
                INC     DI                 ;point to next word of operand2
                INC     DI
                INC     BX                 ;point to next word of sum
             	INC  	BX
                LOOP    BACK               ;if not finished, continue adding
             	MOV  	AH,4CH
                INT     21H                ;go back to DOS
   MAIN      	ENDP
                END     MAIN