help!

[wakeb87]

I'm trying to gain a better understanding for the input and output or "read/echo" in LC-3 assembly language. I was looking at some examples in the back of my book to try and understand it better, however i've just ended up confused. What i'm trying to do is prompt a user to enter a two digit number, i know that i can do something like,
PROMPT .STRINGZ "Enter a two digit number>"

but im unsure as to how i would go about calling it. Eventually i want to understand how to convert that number the user types in, into a hexadecimal. any helps or tips or pushes in the right direction would be great.

this is what i have so far..

.ORIG x3000

READ    LDI R0, KBSR; loads character from keyboard data
            BRzp READ   ; determines if it's a new character
            LDI R0, KBDR; reads the character
            ADD R2, R0, #-9 ; subtracts 9 to see if numbers
            BRnz NUMBER;

NUMBER ; this is wehre i want my loop to be to convert to hex

    
     


ECHO    LDI R1, DSR ; loads the ready bit character
            BRzp ECHO   ; determines if the screen is ready
            STI R0, DDR ; stores the output data to the screen




KBSR .FILL xF300
KBDR .FILL xFE02
DSR .FILL xFE04
DDR .FILL xFE06
PROMPT .STRINGZ "Please enter a two digit number:> "

HALT .END