.model small                            ;.model directive is to specify len of our program
;.386                                    ;80386 microprocessor directive library is installed           

.data                                   ;.data means we are using data segment register
MESS1 DB "Enter 1st 8 digit BCD number: $"   ;message to be displayed on the screen to input 1st no.
MESS2 DB "Enter 2nd 8 digit BCD number: $"   ;message to be displayed on the screen to input 2nd no.
MESS3 DB "                      Sum is: $"   ;message to be displayed on the screen to display sum.
ERR DB "INVALID ENTRY!! Enter the complete no. again $"
N1 DB 4 DUP(?)
N2 DB 4 DUP(?)
ARR DB 4 DUP(?)
.code                                   ; .code means our program code follows here 
.startup                                ; now the program starts

MOV DX, OFFSET MESS1                    ;offset of mess1 passed in DX
CALL MSG                                ;procedure to display message
MOV CX,04
MOV DI,0
RD1:CALL NUMB                               ;procedure to input 32bit no.
MOV N1[DI],BL
INC DI
LOOP RD1
                                
CALL LINE                               ;line break

;---------- SECOND NUMBER ------------

MOV DX, OFFSET MESS2                    ;offset of mess2 passed in DX
CALL MSG                                ;procedure to display message
MOV CX,04
MOV DI,0
RD2:CALL NUMB                               ;procedure to input 32bit no.
MOV N2[DI],BL
INC DI
LOOP RD2
                               ;procedure to input 32bit no.
CALL LINE                               ;line break

;---------- ADDITION CODE ------------
MOV DX, OFFSET MESS3                    ;offset of mess3 passed in DX
CALL MSG                                ;procedure to display messagePOP EDX
DEC DI
MOV CX,03
MOV AL,N1[DI]
ADD AL,N2[DI]                               ;add two 32bit numbers
DAA                             ;store the result in EBX
MOV ARR[DI],AL

L2: DEC DI
MOV AL,N1[DI]
ADC AL,N2[DI]                               ;add two 32bit numbers
DAA                             ;store the result in EBX
MOV ARR[DI],AL
LOOP L2
JNC JUMP8                               ;jump if sum is 32bit no.
;XOR EDX,EDX                             ;clear EDX
MOV DL,01H                              ;copy carry in DL if sum is > 32bit no.
CALL OUTPUT                             ;procedure to display carry

;---------- OUTPUT SUM -----------------

JUMP8: 
;XOR EBX,EBX
MOV CX,04
MOV DI,00
L7: 
MOV DL,ARR[DI]
    AND DL,0F0H                            
    SHR DL,4

CALL OUTPUT                             ;procedure to display sum
MOV DL,ARR[DI]
    AND DL,0FH
                                  ;check counter status
CALL OUTPUT
INC DI                             ;procedure to display sum
LOOP L7
;------------ THE END --------------

.exit                                   ;exit to DOS

LINE PROC NEAR
;---------- NEW LINE -------------
MOV DL,0AH
MOV AH,02
INT 21H
RET
LINE ENDP

MSG PROC NEAR
;---------- TYPE MESSAGE -------------
MOV AH,09H
INT 21h
RET
MSG ENDP

OUTPUT PROC NEAR
;---------- convert to ascii ---------
ADD DL,30H
MOV AH,02
INT 21H
RET
OUTPUT ENDP


NUMB PROC NEAR
;-------------- INPUT NUMBER -----------
L1: MOV AH,01
INT 21H
SUB AL,30H
CMP AL,09
JBE JUMP1
CALL LINE
MOV DX, OFFSET ERR
CALL MSG
JMP L1
JUMP1: MOV BL,AL 
SHL BX,4

MOV AH,01
INT 21H
SUB AL,30H
CMP AL,09
JBE JUMP2
CALL LINE
MOV DX, OFFSET ERR
CALL MSG
JMP L1
JUMP2: ADD BL,AL
RET
NUMB ENDP

end                                     ;end of program