Write a program to Pack the Two Unpacked BCD Numbers in Assembly Language .We have two digits available in the AL and BL registers in unpacked BCD form. The digit in BL is the LSB, whereas digit in AL is MSB. To pack the two numbers, means to combine the two numbers.To make the digit in AL as MSB we rotate it 4 times to the left. i.e. if digit = 09 H, after rotating it by a 4 times it becomes 90 H. Now add the two numbers. Result will be packed BCD. Display the result.
Algorithm to Pack the Two Unpacked BCD Numbers
Step I : Initialize the data memory.
Step II : Load the most significant BCD digit in AL.
Step III : Load the least significant BCD digit in BL.
Step IV : Rotate MSB 4 times to left.
Step V : Add least significant BCD digit into rotated number.
Step VI : Display the result.
Step VII : Stop.
Program to Pack the Two Unpacked BCD Numbers
.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
rcl al,4 ; rotate first number 4 times to make it 90h
add al,bl ; add numbers and result in al
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
l2: 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
l4: 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
How to Run this Program
For Running this program you should have installed Tasm on you computer . If you have not installed Tasm yet please install from Here
C:\programs>tasm packbcd.asm
Turbo Assembler Version 3.0 Copyright (c) 1988, 1991 Borland International
Assembling file: packbcd.asm
Error messages: None
Warning messages: None
Passes: 1
Remaining memory: 438k
C:\programs>tlink packbcd.obj
Turbo Link Version 3.0 Copyright (c) 1987, 1990 Borland International
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