Multiply Two 8 Bit Numbers in Assembly Language
Write a program to Multiply Two 8 Bit Numbers in assembly language . Program should load first number and second number in registers AL and BL registers . Then it should implement some logic for multiplication of two numbers .
Consider that a byte of data is present in the AL register and second byte of data is present in the BL register.
We have to multiply the byte in AL with the byte in BL.
Using MUL instruction, multiply the contents of two registers.
The multiplication of two 8 bit numbers may result into a 16 bit number. So result is stored in AX register.
The MSB is stored in AH and LSB in AL.
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For example :
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AL = 09 H
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09 H
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BL = 02 H
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´
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02 H
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0012 H
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Algorithm to Multiply Two 8 Bit Numbers
Step I : Initialize the data segment.
Step II : Get the first number in AL register.
Step III : Get the second number in BL register.
Step IV : Multiply the two numbers.
Step V : Display the result.
Step VI : Stop
Program to Multiply Two 8 Bit Numbers
.model small
.data
a db 09H
b db 02H
.code
mov ax, @data ; Initialize data section
mov ds, ax
mov ah, 0
mov al, a ; Load number1 in al
mov bl, b ; Load number2 in bl
mul bl ; multiply numbers and result in ax
mov ch, 04h ; Count of digits to be displayed
mov cl, 04h ; Count to roll by 4 bits
mov bx, ax ; Result in reg bx
l2: rol bx, cl ; roll bl so that msb comes to lsb
mov dl, bl ; 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:\>tasm 8bit-mul.asm
Turbo Assembler Version 3.0 Copyright (c) 1988, 1991 Borland International
Assembling file: 8bit-mul.asm
Error messages: None
Warning messages: None
Passes: 1
Remaining memory: 438k
C:\>tlink 8bit-mul.obj
Turbo Link Version 3.0 Copyright (c) 1987, 1990 Borland International
Warning: No stack
C:\>8bit-mul
0012
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