Shooting Gallery

Cracks. Demos. Sceners, Partys...
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Joined: Fri Jun 19, 2015 1:42 am
Location: Canada

Shooting Gallery

Post by mrnop » Wed Jul 26, 2017 8:21 pm

Here's a new shoot up em game which was written back in 1985 by Jerry Cosyn.

From the author:

Back around 1985, I wrote a little video game for a Commodore 64 computer. This was partly for my kids, but also partly as an exercise for myself, to figure out how to do it. I acquired a machine language assembler and a technical manual for the C-64, and spent a few months working on it, programming down to the bare metal of the CPU and the video and sound chips, writing interrupt handlers and time-slice dispatching algorithms, figuring out how to manipulate pixels on the screen to simulate objects in motion, and how to make the background music play (changing keys with each time through the song). Keeping everything in motion and playing the musical tune in the background simultaneously (or at least, giving the illusion that it was happening simultaneously) was one of the challenges, since it required developing my own little customized operating system to run parallel processes in the background on a single processor. It was a lot of fun, and when it was done, I think everybody in the family liked it, but especially my daughter, who was just three years old (and going on four).

Recently, sitting around with a minor head cold and not feeling particularly super, I started reminiscing, rummaging through mementos and bits of nostalgic flotsam & jetsam, and came across the assembler code listing for this little video game program, and I lost myself in reverie of that time thirty-odd years ago. The Commodore computer is long since gone, but I was able to fire up an emulator that will run the C-64 machine code file and make it look (almost) the way it did on the little portable TV we used as the "monitor" for those old computers. This is the "demo mode" screen that describes how to play, and runs a short demo of the game (slightly sped up, as was common for demo screens of video games back then). Ah, nostalgia! How strange that so many years have sped by so quickly. I still have crystal-clear memories of sitting up all night coding on sheets of graph paper, typing in line after line of processor operations, assembling the source code into a machine-runnable object file, testing, and then going back to code some more. The 4am triumphs, the "eureka!" moments when a solution to a problem finally came to me. I got a tremendous amount of enjoyment out of all those hours frittered away, and actually learned a few things in the process, as I started from scratch and made up my own way of doing things.

Maybe now that I've dug it back out of the dust, I'll have to run this little game for my granddaughter, who is now three (and going on four). I wonder, will she enjoy it as much as her mother did, thirty-odd years ago?

Added joystick support, 1 cheat and high score saver.

Download: ... %201hj.d64

Download my C64 software here