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iamgreaser1 year ago (1 edit)

Tried on real hardware (using FreeDOS 1.0), seems to work OK aside from the fact that the keyboard buffer fills up with garbage and then I hear a bunch of beeping. I thought it was the fault of my DPMI server at first (I'm using HDPMI32) but nope, it also happens with DOS4G/W.

Are you able to clear the key buffer every frame?

EDIT: I managed to make a program to temporarily hook INT 0x1C so that I could clear the buffer every theoretically-default PIT tick (~18.22Hz) and that seems to work well enough. Anyway, I probably get about 5-6 FPS on a 266 MHz Celeron (Pentium II type).

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Grumpy Games1 year ago

Hi! Thanks!

Yes, I think the problem was I foolishly chained old keyboard interrupt handler to mine (first experience with it). I fixed and reuploaded it, sorry!

Great! If it's desktop Celeron 266 then it's Covington without L2 cache and quite a bit slower than Pentium II or Celeron Mendocino. Memory subsystem speed is quite important for this type of engine, there is ~330 thousands memory lookups per screen for terrain height and color. Probably even Pentium 233 MMX with L2 cache on motherboard can be faster I think (but right now I don't have the hardware to try, so than you for testing!

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iamgreaser1 year ago

Thanks for fixing it, it now works fine out-of-the-box.

And yeah, I did know that the Covington was a bit weak. But maybe I should try optimising a game specifically for this CPU - having a 16 KB data cache might be manageable for some funky stuff...

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