Mastering Machine Code on your Commodore 64

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?

Ghosts ‘n Goblins is much easier..

Games are a hell of a lot easier when they’re trained! Ghosts ‘n Goblins was one of the first games I dived into to see how it worked back in the day. Earlier I played a remix of it’s soundtrack and fired up the game afterwards. I remembered it was hard but compared to games today it’s a demon!

Luckily it was trained and my son and I had an enjoyable half hour shooting the baddies and jumping from platform to platform. I wish the compatible joysticks from back then had more than one button, left/right and up to diagonal jump is a PITA!

In case you’re wondering, a trained game is where the game has been hacked and various cheats added. Usually a fancy intro with swirling graphics and music is added at the start and the group that has hacked the game give you the option of adding infinite lives, time, invulnerability or whatever suits the games. Practically every C64 game you’ll find online has these features now. :)

Can’t login to Games for Windows Live?

I changed my Xbox Live password recently and found I couldn’t login to GFWL this evening. “No problem”, I thought. Just change the password to my new one.

No, I can’t change the password. I can select the password field. It’s active, I can move the cursor back and forward but I can’t type or delete the * characters.

Luckily it was a simple, if non obvious, fix to get around this. Uncheck the “Save my e-mail address and password” and “Sign me in automatically” checkboxes. Now you can select the password field and change it. Don’t forget to “remember” the password again..

Yes, Games for Windows Live is a POS.

1:51 of utter cuteness

If you’ve had enough of SOPA, PIPA, ACTA, bailouts, the Euro defaulting, rising oil prices and the rest of the bad news you’ll enjoy this video.

By chance we have a Shitzu at home and a black and white cat (daughter of this cute little fella). They’re friendly but not like these two!

I expect this video will be pulled from Youtube just as soon as the copyright holder matches the song.. Oh well. :(