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

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.

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

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