How to convert ASCII number into decimal number

[BrightLight]

Hello, I need help.
Let's say we have this code:

Code: Select all

mov si, number
call change_number

number			db "80"

As you can see, the number is actually a number in ASCII text. How do I convert this to 80 itself (non ASCII)? I don't mind if you tell me to do it in hex or decimal, both are fine.
Help will be greatly appreciated!

[alexfru]

I'd expect OS devers to be able to either figure out trivial things like this on their own or have sufficient google-fu skills.
What have you tried?

[BrightLight]

What have you tried?

Pretty much everything, there's nothing on this topic anywhere.
Just if it may help, I'm doing this in NASM.

[Combuster]

The first attempt at finding the answer provided one. Case dismissed.