Uze8 - Chip8/SChip emulator!

Use this forum to share and discuss Uzebox games and demos.
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omundodogabriel
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Uze8 - Chip8/SChip emulator!

Post by omundodogabriel »

As you may have seen, I've been working on an chip8 emulator for Uzebox these days. The major limitation of Uzebox is the small Ram, with only 4k. Making an emulator with 4k of RAM is an almost impossible task. However, chip8 is a simple system which have only 3.2 kb of RAM.

Thanks to help from Uze6666, who created the video mode 12 with resolution of 64x32 and 128x64 with 1bpp, I could emulate the chip8 and schip full resolution. He also ported FATFS and PetitFS for Uzebox, needed to make a sd card file browser for uze8. :D

Using the emulator is very simple, just select a Chip8/Schip Rom and play.

Working:
SD Card Browser & Load ROM
Menus
Sound
Full Chip8 RAM (SChip RAM not complete, some ROMs may not work)

Not working properly
SChip Games & Some big Chip8 games
Reset function
Controls for some games

Screenshots soon... :)

Sorry for my bad english...

Downloads
v1.0.5 (First End-user release)
Uze8.hex
(85.1 KiB) Downloaded 1038 times
uze8.uze
(30.75 KiB) Downloaded 1140 times
Uze8_105_src.zip
(926.43 KiB) Downloaded 652 times
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uze6666
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Re: Uze8 - Chip8/SChip emulator!

Post by uze6666 »

Great work and thank for sharing! All my hardware is packed since I'm moving this week, but I'll te give it a spin as soon as I get a chance.

Have some pictures so we can post on Facebook and make a news post?
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omundodogabriel
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Re: Uze8 - Chip8/SChip emulator!

Post by omundodogabriel »

Today I found a bug that was causing some chip8 games to only show black screen (like rush hour). Already fixed. :D

Version 2.0 will be released soon, with several interesting news! Stay tuned!
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uze6666
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Re: Uze8 - Chip8/SChip emulator!

Post by uze6666 »

Great! :P
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danboid
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Re: Uze8 - Chip8/SChip emulator!

Post by danboid »

Hi omundodogabriel!

I'm a decade late in saying so but congrats in writing the first Uzebox emulator! It would seem we now have a second as Uze has written an i8080 emulator for the UzeboxPC.

Unfortunately the Uze8.uze file doesn't run under cuzebox although I've not been able to try it on a real Uzebox yet:
$ cuzebox uze8.uze
CUzeBox 20200829
UzeRom parser: Error: uze8.uze is not a UzeRom file.
Hex parser: Error: Invalid content on line 1 in uze8.uze.
I was trying Uze8 because I wanted to try runnng chip-8-bad-apple

https://github.com/Timendus/chip-8-bad-apple

but unfortunately it doesn't run under Uze8, probably because its too big?
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D3thAdd3r
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Re: Uze8 - Chip8/SChip emulator!

Post by D3thAdd3r »

I think this suffered some bitrot, there is an undefined warning and the .uze I can build on my side is > 62K. Removing the built in demo fixes the size, but I either broke packrom or somehow the .uze doesn't work when the .hex does.

Tried Bad Apple on the .hex(which can run games seemingly) and it immediately hangs. Will take a look later, it would actually be nice if this could use SPI RAM if available. I would think the performance would be drastically better with that, and maybe some modern improvements we have to the SD code.
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danboid
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Re: Uze8 - Chip8/SChip emulator!

Post by danboid »

It would be good to see this fixed up as one of only two working emulators available on the Uzebox.

Didn't you mostly get an emulator for the Arduboy written DA? Or was it the Arduinocade? There was at least one other platform you seemed pretty confident that the Uzebox might be able to emulate well IIRC. I presume you didn't have time to finish or optimise it, whatever it was.

I'm pretty sure you concluded a 2600 emulator wasn't possible.
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D3thAdd3r
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Re: Uze8 - Chip8/SChip emulator!

Post by D3thAdd3r »

I wont attempt 2600, it's literally impossible(I think even CF wouldn't attempt this). I tried Channel F but failed to get anything approaching real time. To be fair that makes sense, since even Chip 8 isn't running super fast. That 8080 emulation is the most impressive on Uzebox I've seen. In theory it could be faster with 64K SPI RAM(not needing that last addressing byte for random access). I almost think it's worth it, but since there is a wait loop on SPI RAM it might be possible to support either for no loss.

Arduboy, Gamebuino, some Pico8*, etc. They could be "source ported" but not emulated. Would really depend on the game, there was specifically this Tower Defense game and an Artillery game(forgot the names) which I got addicted to. Just lost interest, wanted to try and see how easy it might be. Lost interest basically.

It would be interesting to see what the minimal Chip 8 like could still be able to do games. It could be used then for instance to save space on game logic in an RPG or something. And not even about saving space, just being able to execute code even in a around about way from the SD card.
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