My original goal was to have this working at all by March 31. When I started, it seemed daunting enough that I gave myself more than 6 weeks to get it done. It took 6 days.
At my lunchbreak I had it working as a script
And after work I refined it to take user input.
My goal here was to learn it, not make a downloadable program for actual use. Something like CRC or MD5 works much better on a 6510 processor, this it much to slow to be useful.