Objective
Write a Program to Multiply Two 16 Bit Numbers in Assembly language . Program will ask for two numbers to be multiplied and should store those numbers in AX and BX Registers . Now it should implement certain logic to both numbers to find the result.
Consider that a word of data is present in the AX register and 2nd word of data is present in the BX register. We have to multiply the word in AX with the word in BX. Using MUL instruction, multiply the contents of the 2 registers. The multiplication of the two 16 bit numbers may result into a 32 bit number. So result is stored in the DX and AX register.
The MSB of result is stored in the DX register and LSB of result in AX register.
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AX = 1234 H
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1234 H
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BX = 0100 H
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´
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0100 H
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23400 H
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Algorithm to Multiply Two 16 Bit Numbers
Step I : Initialize the data segment.
Step II : Get the first number in AX register.
Step III : Get the second number in BX register.
Step IV : Multiply the two 16 bit numbers.
Step V : Display the result.
Step VI : Stop
Multiply Two 16 Bit Numbers Flow Diagram
Program to Multiply Two 16 Bit Numbers
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<span style="font-family: 'times new roman', times, serif; font-size: 14pt; color: #000000;"> .model small <br/> .data <br/> a dw 1234H <br/> b dw 0100H <br/> .code <br/> mov ax, @data ; Initialize data section <br/> mov ds, ax <br/> mov ax, a ; Load number1 in ax <br/> mov bx, b ; Load number2 in bx <br/> mul bx ; multiply numbers. Result in dx and ax <br/> mov si, ax <br/> mov bx, dx ; Result in reg bx <br/> mov dh, 2 <br/> l1: mov ch, 04h ; Count of digits to be displayed <br/> mov cl, 04h ; Count to roll by 4 bits <br/> l2: rol bx, cl ; roll bl so that msb comes to lsb <br/> mov dl, bl ; load dl wth data to be displayed <br/> and dl, 0fH ; get only lsb <br/> cmp dl, 09 ; check if digit is 0-9 or letter A-F <br/> jbe l4 <br/> add dl, 07 ; if letter add 37H else only add 30H <br/> l4: add dl, 30H <br/> mov ah, 02 ; Function 2 under INT 21H (Display character) <br/> int 21H <br/> dec ch ; Decrement Count <br/> jnz l2 <br/> dec dh <br/> cmp dh, 0 <br/> mov bx, si <br/> jnz l1 <br/> mov ah, 4cH ; Terminate Program <br/> int 21H <br/> end</span> |
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 . More assembly language codes can be found here.
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<span style="font-family: 'times new roman', times, serif; font-size: 14pt; color: #000000;">C:\programs>tasm 16-m ul.asm<br/>Turbo Assembler Version 3.0 Copyright (c) 1988, 1991 Borland International<br/>Assembling file: 16-mul.asm<br/>Error messages: None<br/>Warning messages: None<br/>Passes: 1<br/>Remaining memory: 438k<br/>C:\programs>tlink 16-mul<br/>Turbo Link Version 3.0 Copyright (c) 1987, 1990 Borland International<br/>Warning: No stack<br/>C:\programs>16-mul<br/>00123400<br/></span> |
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