This exercise requires you to write an ARM program that can read a decimal integer greater than or equal to zero $($you can ignore negative numbers$)$ that the user types into the keyboard, store the result in memory, and print it out. Unfortunately, Komodo only provides a mechanism $($SWI $1)$ to read raw ASCII characters from the input, not integers, so you will need to implement a routine to convert the sequence of ASCII characters into the integer number entered. Again, as with the exercises last week, you are only provided with a simple skeleton this time.

Your routine will need to do the following:

Print out a prompt for the user asking them to enter a number $($the prompt string is provided for you labelled as enterI$)$

Repeatedly read characters from the keyboard and if they are digits convert it from the ASCII code returned by SWI $1$ into a number. Conveniently, ASCII lays out the digits $\text{'}0\text{'}\text{'}9\text{'}$ in order with the integer codes $4857.$

Note that SWI $1$ does not print out the character input, so you will need to print the character out so the user can see what they typed...

Build up the integer being typed from the digits being typed $($remember that each digit entered represents a power of ten entered so multiplying by $10$ is your friend here...$)$

The number is ended when the RETURN $/$ ENTER key is pressed $($returned by SWI $1$ as the ASCII code $10,$ that is R$0$ will contain the number $10).$

If any other non$-$digit characters are entered, then this should cause an error message to be printed $($on a new line$),$ and the input is restarted by printing the prompt again $($an error message is provided as errorM$).$

Store the integer entered into the memory location labelled value and then print it out using SWI $4.$ The code to print out the stored value is provided for you.

Hint: Build this up in stages, e$.$g$.$ start by just reading keys until RETURN is pressed, then handle building up the integer, then add error handling etc. The order or steps is not important, but don$$t try to implement it all in one go$.$

Further Hint: Remember, $123,$ is one hundred plus two tens plus three, and that one hundred is $10$x$10,$ ten is just ten, units have no tens, or $1$x$10$x$10+2$x$10+3.$ I hope you$$ve remembered your algebra classes...