I took an old Super Mario Brothers Nintendo video game and erased everything but the clouds. In section 1 is the source code with commentary, and in section 2 is a little tutorial on how to make your own version of this cartridge if you aren’t afraid of soldering irons.
Below I will go through the source code line by line. To compile this code you will need dasm and nbasic. nbasic is a small assembly wrapper for the Nintendo. The idea here is to simply write a program that will take the clouds from Mario Brothers and scroll them across the screen. Here comes the first line of code:
(beware, it’s assembly) :0