4 digits BCD Arithmetic (Addition and Subtraction of BCD numbers each 4 digits).

2).4 digits BCD Arithmetic (Addition and Subtraction of BCD numbers each 4 digits).

Addition:

.model small
.386
.data
DATA DW 0000H
msg db 10,13,"Enter the first no.:: $"
msg1 db 10,13,"Enter the second no.:: $"
msg2 db 10,13,"The Resultant sum is :: $"
.code
.startup
MOV AH,09
MOV DX,OFFSET msg
INT 21H
MOV BX,0
MOV CX,4
AGAIN: MOV AH,01 ;1ST NO. ENTERED
INT 21H
CMP AL,'A'
JGE L2
SUB AL,30H
SHL BX,4
ADD BL,AL
LOOP AGAIN
MOV DATA,BX
MOV AH,09
MOV DX,OFFSET msg1
INT 21H
MOV BX,0
MOV CX,4
AGAIN1:MOV AH,01 ;2nd NO. ENTERED
INT 21H
CMP AL,'A'
JGE L2
SUB AL,30H
SHL BX,4
ADD BL,AL
LOOP AGAIN1
MOV AX,DATA
MOV CX,0
ADD AL,BL
DAA
MOV BL,AL
ADC AH,BH
MOV AL,AH
DAA
MOV BH,AL
MOV AH,09
MOV DX,OFFSET msg2
INT 21H
MOV DX,0
MOV CX,4
AGAIN2: ROL BX,4
MOV DL,BL
AND DL,0FH
ADD DL,30H
MOV AH,02
INT 21H
LOOP AGAIN2
L2: .EXIT
END

Subtraction:

.model small
.386
.data
DATA dW 0000H
msg db 10,13,"Enter the first no.:: $"
msg1 db 10,13,"Enter the second no.:: $"
msg2 db 10,13,"The Resultant is :: $"
.code
.startup
MOV AH,09
MOV DX,OFFSET msg
INT 21H
MOV BX,0
MOV CX,4
AGAIN: MOV AH,01 ;1ST NO. ENTERED
INT 21H
CMP AL,'A'
JGE L2
SUB AL,30H
SHL BX,4
ADD BL,AL
LOOP AGAIN
MOV DATA,BX
MOV AH,09
MOV DX,OFFSET msg1
INT 21H
MOV BX,0
MOV CX,4
AGAIN1:MOV AH,01 ;2ND NO. ENTERED
INT 21H
CMP AL,'A'
JGE L2
SUB AL,30H
SHL BX,4
ADD BL,AL
LOOP AGAIN1
MOV AX,DATA
SUB AL,BL
DAS
MOV BL,AL
SBB AH,BH
MOV AL,AH
DAS
MOV BH,AL
MOV AH,09
MOV DX,OFFSET msg2
INT 21H
MOV CX,4
AGAIN2: ROL BX,4
MOV DL,BL
AND DL,0FH
ADD DL,30H
MOV AH,02
INT 21H
LOOP AGAIN2
L2: .EXIT
END