japanese-cake

Demo time soon: custom #dreamcast bios with embedded app loader running on real hardware. #Sega genuine looking and new features combo. I hope you’ll enjoy it!
Meanwhile, converting sh4 assembly code to c, because, well, gcc does better job than me 😂

just for fun, I put together some comparison clips of tile skewing vs scanline subdivision, plus some bonus debug visualization 🧵

you'll have to bear with me tho. bluesky only allows 1 video per post, so there's gonna be a lot. upside: more yapping, more nerd details.

1/9

The #dreamcast bios is interesting in its structure: a bootstrap, an app controller then 2 apps, the bootanim and main menu.

The bootanim app is able to run normally, run just its init phase or just run the splash screen. The latter
2 run modes are used when there is no disc 💿

Attempting to control the switch between a #sega katana and a #kos app within the bios so that a kos app can perform a couple of tasks while booting the bios. Definitely not easy. The kos app runs but I cannot switch back to the bios app. I hope not to waste days on this!

💕 I can’t be grateful enough to all #kos contributors for bringing such an elegant and powerful dreamcast makefiles system!

I’ve mimicked a part of it in my bios codebase and everything looks so nice. Non-kos and kos worlds are now living together, for the best I hope 😅

✅ Dreamcast Bios compression: done

✅ Menu and bootanim heap trim and relocation: done

✅ Custom library relocation in ram: done

Now a sd/ide backend and space consuming features such as localization can fit in!

Is there a reason why a dreamcast kos based program would access to the bios font directly (with an hardcoded bios font base address rather than obtaining it via a syscall)?? With the compression being implemented in the custom bios, the bios font is likely to be relocated

The new bios version is still in development but will be available to all once released. As for the v2 dc, either buy programmed chips or buy blank chips and use an ISP with a sop44 adapter to write the bios in it before soldering them ;)

Hi!! Could probably be doable but I am focused on my custom bios right now and patching this game requires additional work on texture sizes and placements. But I add it to my todo list :)

To host the future sd (+ide?) backend in the #dreamcast bootrom, I needed space, ~300kb which is far more than anything I could get by stripping out stuff. I have two impls of the compression, one is the most efficient storage wise while the other is more elegant and maintainable

I didn’t believed it would gave taken that much time to get it work properly! But here is a quick keyboard demo for the dreamcast bios. Both large and small keyboards are supported btw.

Got my answer: balign is the way to go!

Here again, #gas #sh4 source code formatting questions: is there any standard way to comment functions in assembly? While temporary & context registers don’t need to be documented imo, if parameters are being overridden, how to reflect this in the comment?
#dreamcast #kos

« .align 2 » or « .balign 4 » ? For gnu assembly devs, when both work, why would I use one or the other? Context here: sh4 assembly dev, no portability. I personally use the balign directive align operands in text section, I find more intuitive. Any thoughts? #dreamcast #assembly

GitHub - NotAFlyingGoose/AsmFormat: A vscode extension for formatting .asm files A vscode extension for formatting .asm files. Contribute to NotAFlyingGoose/AsmFormat development by creating an account on GitHub.

Thanks!! Gonna give it a try :) the one I am using is « notaflyinggoose.asmformat »

github.com/NotAFlyingGo...

@falcogirgis.bsky.social maybe you know ;)

I’ve found an extension for assembly syntax highlighting for vscode. I am now looking for sh4 assembly linting and also function comment template. How do you guys do? Any templates to share?

Another day, another glitch! I’ve tested my new #dreamcast bios on real hardware and there is a little glitch when entering the custom settings menu with the 3d scenery enabled. Good point though: I can reproduce it on emulators. Should not take to long to fix 🤩

I'm porting the classic Prince of Persia for #dreamcast. 🙂 SDLPoP is now available for Dreamcast. You can play the classical way against the time or use a quicksave feature (which will cost you time⌛).

The talk I gave on behalf of the Sega Dreamcast indie scene in Brussels for the GCC Devroom at FOSDEM 2025 is now live!

Deep-dive C, C++, ASM, and even Ada code running on the DC using the latest GCC toolchain, with footage from Mario 64, Sonic Mania, Doom64, and GTA3!

fosdem.org/2025/schedul...

I didn’t test all the latest changes of my custom bios on real hardware.. well, a couple of « slot illegal instruction exceptions » later, it works 🤪 #dreamcast