NASM Program for Data Conversion

As discussed in the class, the operating system $($kernel$)$ function int $0$x$80$ reads and writes

character data only and you must convert the charcter data into the appropriate binary data

before performing computations on it and covert the internal binary results into character

strings before printing them out. In this programming assignment you are going to write the

necessary NASM assembly language code to do these conversions.

Write a NASM assembly language program to do the following.

Read a signed integer number $($up to $4$ digits$)$ from the standard input device $($keyboard$)$

using the int $0$xx$80$ kernel function.

Print the input data $($exactly as read$)$ on the standard output device $($screen$)$ using the

int $0$xx$80$ kernel function with a description like $($if the input number is $-1234)$:

The entered number is $-1234$

Convert the character data read into the corresponding signed integer data using a simple

for loop. Note that if the input character string $($positive number$)$ is d$\_(3)$d$\_(2)$d$\_(1)$d$\_(0),$ the

corresponding binary value can be computed using the following.

value $=$ d$3-48$;

for $($i $=2$; i$>=0$; i$=$i$-1)\{$

value $=$ value$*10+$di

$\}$

You should similarly convert a negative number taking care of its sign properly. Keep the

converted binary integer in both the eax and ebx registers.

Divide the input data by two by shifting the contents of the eax register to the right by

one bit. Convert the result into the appropriate character data using a simple do while

loop. Note that the digits $($d$\_(3)$d$\_(2)$d$\_(1)$d$\_(0))$ of the character string corresponding to the result

value $($positive number$)$ can be computed using the following.

i $=0$;

do $\{$

di $=$ value$\%10+48$; $//$ remainder

value $=$ value$/10$; $//$ quotient

i $=$ i $+1$;

$\}$

while $($value $>0)$;

Again, you should handle negative results appropriately. Print the resultant data

correctly with a description like

Half of the entered number is

Multiply the input data by two by shifting the contents of the ebx register to the left by

one bit, convert the result into the corresponding character string and print the resultant

data correctly with a description like

Double of the entered number is