Gba Emu

[pip]

Squidge, give the guy a hand then since the BIOS is your area of expertise. Then I would even forgive you for not making gpdrive work under win9x

 

[Efompor]

Here are the actual threads

original thread

BableFish Translation

 

[khephren]

Its really good to see someone finally trying this method of GBA simulation, fingers crossed it comes to something as it should be fast.

-Craig

www.gbax.com

Yeah, it's something that we've all discussed to death From what I can make out from the translation, it all seems kosher to me- here's hoping (not that I would have much time for GBA stuff, SNES, DOOM and ST are keepng me busy as it is!)

 

[c0ncept]

ha! I doesn't really matter anyway, I HAD a GBA and the best games on it seem to be SNES ports anyway! Talking of the SNES, I can't wait for opensnes9x 0.3!!!!

 

[Mosch]

ha! I doesn't really matter anyway, I HAD a GBA and the best games on it seem to be SNES ports anyway! Talking of the SNES, I can't wait for opensnes9x 0.3!!!!

You have obviously never played Golden Sun, those games are really great RPGs. Concerning 0.3, yes, I await it eagerly, too

Now the whole GBA emulation thingy: I would really like GBA-emulation. I admit it: I already have a GBA. But having and emulated one will never be like having the real thing, which I can hook up to my Gamecube and use to play with my friends. I really only want emulation so I can fit more games on smaller space I will and would still buy games for my GBA if they are good.... I just have too high a moral *sniff*

 

[Charge]

If this method works, it could turn into the must have emu, as emulation of the cpu core in this way could mean it will be faster than any snes emu could be.

 

[pubjoe]

Sounds interesting. If it works, could the same method be applied to SNES etc?

[edit] It'd be russian roulette flashing the bios every time a new emulator comes out!!

 

[pip]

Sounds interesting. If it works, could the same method be applied to SNES etc?

No, this would only work on a system also using a 32-bit ARM CPU (which both the GP32 and GBA uses).

 

[MojoJojo]

Wow,I'm glad someone is trying this approach. I'd started to get tempted to try it myself, but I don't really have the skills for it.

Couldn't do this for SNES or other system as they don't use ARM chips. (Although I suppose you could possibly "translate" the snes opcodes to ARM code on loading... have no idea if they are compatible or not though. And your addressing would go all screwy. So no then. Just thinking out loud, sorry).

Not sure what the bios talk is about. I think you need to right your own version of the GBA bios, but that's not too bad because it doesn't do to much and it has a well defined interface... I don't think he can be trying to fit the emulator into the bios, since it would really gain you much. You still have less than 8 meg of space to store the cartridge, since your code will need working space (can't do this in flash), and you need some space for the GBA ram too. So you still need to do dynamic loading for the ROM, and I doubt the space you could save by moving emulator code to flash would make enough performance difference to justify flashing...

Sorry I'm just waffling...

 

[khephren]

I think he's running the GBA ARM code direct. In affect turning the GP into a GBA, without emulation of the CPU. As such the cartridges will be looking for the ROM in at a certain address, exactly where he is planning on putting it...

 

[Squidge]

Squidge, give the guy a hand then since the BIOS is your area of expertise. Then I would even forgive you for not making gpdrive work under win9x

Erm, no it's not I do know things about the BIOS, but it's certainly not my area of expertise. I've also got no spare time left whatsoever.

Hopefully however, most of the memory map of the GBA will be able to be remapped by using the MMU of the ARM processor (turning the GBA memory into virtual memory to be mapped in hardware to physical addresses in the GP32).

 

[khephren]

Yep aren't you glad we got the ARM9 with MMU? (now we've found a use for it, at any rate!)

 

[pip]

Erm, no it's not I do know things about the BIOS, but it's certainly not my area of expertise. I've also got no spare time left whatsoever.

I actually managed to confuse you with Spiv, your names are so similar, I am sorry for any inconvenience it may have caused.

Any how, I think people are a little too excited, the fellow who is making the emulator has not even started doing the actual emulation yet not has he decided if he wants to make it himself from scratch or choose an already existing emulator (VBA). Remember that yoyo who is one of the fastest and best coders, started coding osnes9x in july and it took several months just to get it to a fairly playable state (it is still not finished).

 

[Rico]

Nobody drop your SP in the trash yet, but this deeply intrigues me. I did think, since both chips are ARM that there might be a way of bypassing emulation altogether (much like WINE does, passing Windows x86 instructions directly to the processor). But I dismissed it as I didn't know much about low-level programming in general. Now I get this news, it seems it is possible, and that's obviously great. I have great faith in Enf65 that something good will come out of this!

 

[Skeejay]

Since he's messing with the mmu and bios, it seems like he's trying to turn the gp32 into a gba rather than emulating it. I can see his method here - instead of trying to emulate the arm7, get the arm9 to execute the code instead, and manage the memory through mmu register manipulation. If you can get the gba rom in the correct place in memory, you don't have to trap calls to that either

What about that special GBA graphical chip? How will that be emulated then...



note that i am a complete coding nitwit....

 

[Squidge]

Depends how it used, if it's mapped into normal ram, then surely marking the page as no-access with the mmu would generate an exception upon any access to it, which could then be emulated and returned from the exception.

 

[unlucky]

i guess if most of the instructions came in native to the processor then thers plenty of mhz left 2 do some nifty emulation of the extra chips

 

[lizard808uk]

How long is it to April Fools day?

 

[BaDToaD]

Sounds like a viable project to me.

When Mac emulation came out on the Amiga via shapeshifter an Amiga with the same processor as the Mac it was emulating was actually quicker than the Mac. The Amiga ran the 68k code in native mode and the custom chips more than made up for the macs simpler gfx system. The end result was an emulated Amiga Mac system that was faster than the equivalent Mac by a few percent.

Obviously the GP32 doesn't have the custom chips but it does have a big helping of extra speed over the GBA.

 

[Sponge BoB]

squidge, u still working on a port of BOR, if so any news?

I have this game for the dreamcast, it would be great on the gp