Before the internet became popular and the web was still in diapers I had a Commodore 64 at home. “Mastering Machine Code on your Commodore 64” by Mark Greenshields was the first programming book I owned that wasn’t full of BASIC listings and opened my eyes to the wonders of low level assembly development. It was a daunting task learning machine code on my own but I devoured the book and learned so much by looking at the code in demos and games of the time.
The book was originally published in 1984, and I discovered it in a small bookshop next to Paul Street Shopping Centre in Cork sometime in 1990 or 1991. I still remember the excitement I felt at finding any book on the subject. The city library had books on computers, even one or two on building robots and things you could connect to a computer but nothing that explored the C64 in depth.
Based on what I learned in that book and from hacking demos with the aid of an Action Replay I was able to do quite a bit. Nothing amazing but I’m proud of what I did along with others in my demo group way back 20 years ago. I was 16 at the time. I wonder what I’d be hacking on now if I was that age?
You can find a zip file with all our demos in this post. Commodore 64 emulator required!
While flicking through the book I stumbled upon a favourite section, the one on interrupts which I’ve scanned and posted the first two pages of in this post. Here’s another doc on this subject, with the same example code flashing the border 60 times a second. Happy memories.
What was your first programming book?"Mastering Machine Code on your Commodore 64",