PS one game compatibility

[refraction]

Yeah don't get excited, I did this before about 2 years ago It's also only the interpreter and doesn't do much apart from get rid of some unknown opcodes.

[sethomega]

EDIT: Sorry... I distracted myself reading stuff from you developers and forgot that I'm not allowed to post here. Remove this post please. Sorry again.

[Nobbs66]

Dude, it's not a big deal that you posted in dev discussion.

[truemaster]

the pcsx reloaded team have the source code and i thing its an open code for everyone. if a dev of pcsx2 have some time free maybe can dig something from the source code

[refraction]

Thanks for the offer but PCSX Reloaded was taken from PCSX, made by the original PCSX2 team, which they used as a basis for PCSX2, all that code (which was required) is already in there. There is more to this than just putting a PS1 emulator inside a PS2 emulator, we are trying to do it as the PS2 does it, not just fake it, but not all the PS1 hardware is in the PS2, for example the GPU is completely missing.

[Nobbs66]

Thanks for the offer but PCSX Reloaded was taken from PCSX, made by the original PCSX2 team, which they used as a basis for PCSX2, all that code (which was required) is already in there.  There is more to this than just putting a PS1 emulator inside a PS2 emulator, we are trying to do it as the PS2 does it, not just fake it, but not all the PS1 hardware is in the PS2, for example the GPU is completely missing.

I'm sure it'll take testing on actual hardware with a mod chip like Rama stated.

[refraction]

We have already run some tests on a PS2, the problem is what isn't available without the PS1 driver in the BIOS running that will be a pain, beyond that it's trial and error.

[truemaster]

We have already run some tests on a PS2, the problem is what isn't available without the PS1 driver in the BIOS running that will be a pain, beyond that it's trial and error.

if i get you right you need a driver from ps1 bios. i had read something a long ago that ps2 bios the 4096 kb bin have its own ps1 bios. its 2 bioses in one bin.

[Triver]

the pcsx reloaded team have the source code and i thing its an open code for everyone. if a dev of pcsx2 have some time free maybe can dig something from the source code

Mednafen is also open source and I think it has overall better compatibilty than PCSX-R.

There is also no$psx which seems to be the best choice for debugging but unfortunately the source is not available.

Last but not least for PSX information, there is this forum (someone currently seems to be in the process of reverse engineering the entire CPU in the Research subforum?), maybe if required some people there might be willing to help/share information?

But then again this is all PSX emulation only, not PSX-in-PS2 emulation.

[rama]

What we really require is accurate information on the SIF2 unit. It handles data transfers between IOP and virtual GPU on the EE.
To IOP it looks like the regular DMA channel that was present in the PSX. The EE runs the GPU in emulation and receives data from SIF2.
Since the EE "GPU" is a PS2 application, we can assume that it handles the GPU emulation correctly and forms valid images for the GS to draw.

Unknowns are:
SIF2 entirely
the "PGIF" unit
any PSX mode related flags in hardware registers
if CDVD works in PSX mode

Still missing but not as important right now:
MDEC unit in the IOP