32X Support

[Papermanzero]

Could 32X support be added? This would fully complete the emulator.

Edit:
Sorry have not read the closed issues. Another request was already closed.
So this can be closed as well.
Btw could picodrive or gens be used as reference, for 32X emulation?

[Oggom]

This has previously been discussed here https://code.google.com/p/genplus-gx/issues/detail?id=65

32X emulation is just too slow to be portable and run at full-speed on a Wii at the same time

[Papermanzero]

For the Wii it is impossible, without doubt.
But the question is concerning the PC via libretro.

[ekeeke]

See issue #64 here and the one linked above on googlecode, I already answered all these questions and explained the various reasons it has not been done yet many times before...

[Papermanzero]

@ekeeke
Can the effort of these guys be ported?

http://www.1emulation.com/forums/topic/35435-neogensplusgx-v1b02-public-beta-pier-solar-rom-and-cd-new-update/

[ekeeke]

No, because the "effort" was just incorporating Genesis Plus GX code into their old XBOX Gens port and have 2 emulators in one: basically they just switch between Genesis Plus GX and Gens depending on the ROM type so they still use old Gens code for 32x but nothing has been added or modified in Genesis Plus GX core, these are still 2 separated emulators.

Basically, it's like asking if the fact that Retroarch is able to run genesis plus gx core but also 32X through picodrive core can benefit to genesis plus gx.

[Papermanzero]

I see. Thanks for the answer :)

[Papermanzero]

@ekeeke
Just out of curiosity, I am looking what has to be done to add 32x support.
In general the 32x "only" persists of 2x SH2 CPUs (Master-Slave), a custom Sega 32X VDP processor for graphics, 256 KB RAM and 256 KB VRAM (128KB for each framebuffer).

The SH2 CPU could be used from mame:
https://github.com/MisterTea/MAMEHub/blob/master/Sources/Emulator/src/emu/cpu/sh2/sh2.c
https://github.com/MisterTea/MAMEHub/blob/master/Sources/Emulator/src/emu/cpu/sh2/sh2.h

Therefore the only missing part is the communication (architecture) between the system components (memory, genesis CPU and audio). The benefit of Genesis Plus GX is, that the Genesis hardware including the Sega CD hardware are pretty accurate. Consequently the remaining parts are the video processor, the memory and the communication between the SH2 CPUs

[60fpshacksrock]

I know this is an old thread but, I thought I should let you and others who see this post know that picodrive is now on Wii via the latest buildbot versions of retroarch and 32x support is there as well.

As of this posting I can only get it to run 32x on Dolphin by using its cached interpreter, and funnily enough on my Wii by first loading an MD/Genesis game and turning off Dynamic Recompilers. If you make a save state in Dolphin using the cached interpreter, you can then stop emulation, turn on the JIT Recompiler and reload the save state and it (at least Chaotix) runs at full speed. Yes I also know that picodrive is not as accurate as GPGX, but it proves that it (32x on Wii) is doable.

[Arnold101knight]

wii impossible you say? not true lol there is already a 32xemu working fine @Papermanzero

[birdybro]

Please don't necropost something just to argue and pester a developer who spends their time working on something for the community for free. It's very disrespectful and pointless.