There are tons of 6502 assemblers out there. It&#x27;s a pretty easy processor to work with. I wrote maybe half a dozen assemblers back in the day (each one better than the last). On a lark, I wrote one in Python a couple of years ago; it&#x27;s on github (<a href="https:&#x2F;&#x2F;github.com&#x2F;landondyer&#x2F;kasm" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;landondyer&#x2F;kasm</a>).