Add 8 bit BCD numbers
Add 8 Bit BCD Numbers is the program written in assembly language and describes the algorithm of adding two 8 bit BCD numbers through Assembly program code. This program will take numbers as input one by one and then add those BCD numbers. You can find complete steps and algorithm below step by step.
Algorithm :
Step I : Initialize the data memory.
Step II : Get the first BCD number in AL.
Step III : Get the second BCD number in BL.
Step IV : Add the two BCD numbers.
Step V : Using DAA, adjust result to valid BCD number.
Step VI : Display the result.
Step VII : Stop.
Program :
.model small
.data
a db 09H
b db 02H
.code
mov ax, @data ; Initialize data section
mov ds, ax
mov al, a ; Load number1 in al
mov bl, b ; Load number2 in bl
add al, bl ; add numbers and result in al
daa ; adjust result to valid BCD number
mov ch, 02h ; Count of digits to be displayed
mov cl, 04h ; Count to roll by 4 bits
mov bh, al ; Result in reg bh
rol bh, cl ; roll bl so that msb comes to lsb
mov dl, bh ; load dl with data to be displayed
and dl, 0fH ; get only lsb
cmp dl, 09 ; check if digit is 0-9 or letter A-F
jbe l4
add dl, 07 ; if letter add 37H else only add 30H
add dl, 30H
mov ah, 02 ; Function 2 under INT 21H (Display character)
int 21H
dec ch ; Decrement Count
jnz l2
mov ah, 4cH ; Terminate Program
int 21H
end
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