BCD to 7 segment code conversion
BCD to 7 segment code conversion Algorithm
Step I : Initialize the data segment.
Step II : Load the offset of look up table in BX.
Step III : Load AL with key i.e. digit whose 7
segment code is to be found.
segment code is to be found.
Step IV : Compute 7 segment code using XLAT
instruction.
instruction.
Step V : Display the result.
Step VI : Stop.
BCD to 7 segment code conversion Code
.model small
.data
lookup db 01h, 04h, 1Ah, 09h, 02H
key db 02h
.code
mov ax, @data ; Initialize data section
mov ds, ax
mov bx, offset lookup ; Load offset of lookup in bx
mov al, key ; key no. in al
xlat ; translate byte in al
mov bh, al ; al = lookup(key)
mov ch, 02h ; Count of digits to be displayed
mov cl, 04h ; Count to roll by 4 bits
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
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