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A little CoCo BASIC gaming action


JamesD

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I just sent him another page worth of optimizations to use, so it's going to get faster. :D
The program uses PCOPY for double buffering, which copies from one 3K graphics page to another, and it does that A LOT!

There's going to be a faster USR function at some point for the copy and it should make a big difference.
If I get off my butt and release a few more patches for the CoCo 3, that should make it faster as well.

People don't realize it, but the CoCo was no slouch speed wise even though Microsoft didn't fully take advantage of the 6809.
In high speed mode (POKE65495,0) the CPU runs at double speed when accessing ROM... and BASIC is in ROM.

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I gotta know, and it's probably a silly question, but how did y'all figure out how to make BASIC run like this? I remember seeing game submissions in Rainbow or Hot CoCo and wondering how the heck the programmer made it work.

 

I've been thinking of reviving some of my Dad's old game projects he started years ago and finishing them. While I have to reaquaint myself with BASIC, it's something I've wanted to do since he passed away almost four years ago. Makes me glad I backed up his old CoCo disks to file images!

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All my stuff avoided the PCOPY. But Stevie's not quite fully grasped how to erase old sprites when flipping pages.
Once he gets more of the stuff I've suggested incorporated, I may just change the code for him.
Sometimes you need to see it in action to get a handle on it.

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You may be better off avoiding the PCOPY entirely. Just flip between two display buffers. Using PMODE without SCREEN will let you draw to an off-screen buffer.

 

However, BASIC is so slow it may not make a heck of a lot of difference.

I'm pretty sure it will make a noticable difference, but with a faster USR function, it will be much faster without making the code more complicated.

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  • 1 month later...

Dang....that's a lotta stuff. I recognized some CoCo games from magazines that got converted (Richard Ramella's Lurkley Manor comes to mind).

 

Thanks for sharing!

 

Ramella! Years without reading his name! I used to read his 80-Micro columns

 

http://www.trs-80.org/fun-house/

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James, can you post some of your optimization tips here?

 

I think I heard Steve say recently you can disable the BASIC interpreter checking for the BREAK interrupt which leads to a 30% boost. Something like that.

I'll work up a blog post or series of posts on optimizing Microsoft BASIC, and then post a link when available.

 

Stevie hadn't found a working solution for the BREAK disable last I checked.

 

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