Regarding OpenBIOS and original CD audio player of psx

[z1poc]

Hi all,
thanks for the work on open bios.
i was wondering if open bios emulate also what will happen if an audio CD is played.
is this part present or not?

edit:
im trying to understanding the flow from psx-spx by nocash
maybe in the bootmenu option of bios (select between card and cd player) when we select cd player the code used is not entirely the one in the bios but some tasks are done by a separate chip (?)

[nicolasnoble]

So the bios is split into two sections: the kernel, and the shell. The shell is what displays the boot logos, and goes to some utility menu when there's no disc, or when there's an audio CD.

Right now, openbios is a fairly accurate re-implementation of the kernel part, but the shell part is completely different, and is only there to boot the console, without providing any of the utilities of the original shell.

[z1poc]

Thank you

[z1poc]

Hi @nicolasnoble,
Just an additional question.
I'm studying the "shell" part of the BIOS.
I managed to get the original BIOS working by simply renaming it "opebios.bin" and it seems to work fine.
Can you confirm that I can trust the information I get from various debug views of PCSX Redux?
So what happens when we have an audio CD or the built-in PSX memory card manager? (original BIOS).
These should be BIOS independent (as I understand it is a compiled bin file that replaces the original one, and the other part of the emulator tracks the system state nicely without interference).

[nicolasnoble]

I mean, you can run any of the retail bioses into Redux without issue. You can specify which bios file to load inside the settings.

The shell in the retail bios is a separate binary always located at address 0x18000 inside the rom chip. It'll be copied and run from 0x80030000. This is indeed independent, and I've successfully ran it inside openbios in the past, but I haven't tried recently.

But all in all, the emulator doesn't really care nor knows about what's running. For it, it's all a jumble of code.