Question about emulation

[Horscht]

Ok, i have some questions about emulation (2 questions to be exactly)

1. Why do the ROMs of an emulated system need to be loaded into the ROM of the GP32? If you take the GBA for example, it can emulate the GB (mono) with games of 4Megabyte, allthough it only has 256Kb RAM. So on the GBA the ROMs obviously dont have to be loaded into RAM. Wouldnt this be possible for emulation on GP32, too, or would it result in slow speed or something?

2.So now, if there is no way to read ROMs directly from the SMC, why cant os9xGP load files bigger than 4Mb? I mean, the GP has 8Mb RAM, so is the Emu Bigger than 2Mb (uncompressed)? Because i would love to play Tales of Phantasia on my GP32. This is not a request "please make os9xgp load files bigger than the size of my SMC" or whatever, i would like to have some serious answers, since im pretty sure im missing out something

thanks in advance

Horscht

 

[craigix]

The GBA is able to use the flash cart as ROM.

An SMC is too slow to do this, so the internal ram has to be used.

-Craig

www.gbax.com

 

[TeDaDeS]

what about smart precaching ?

pre-loading should solve the slow smc loading times...

This way you could load big files,
and make configuration files with the parts that should be loaded,
on specific times. So your the emu pre-chaching is optimised.


But maybe its to difficult, but i dont think its impossible.
Or does the GBA use ALL of the ROM at one time ?

 

[Robster]

On the GBA, all of the cartridge ROM appears as just another area of memory, and can be accessed with no special actions. On the GP32, accessing the SMC involves writing instructions to the SMC, then reading a bunch of data through an 8-bit port, one byte at a time. This ends up being much slower, especially for random accesses in big files.

So the GBA has a big advantage when emulating large ROMs.

"Smart precaching" or other techniques could work, but they are complex and I can't see them coming into widespread use.

Of course, if more people upgraded their GP32s to 32MB like on my website, then emulator coders would support it and we could load those big ROMs easily

 

[johncross85]

How about dumb pre-caching? The emu just pauses while it gets another big chunk which would be damn irritating if in the middle of a tricky level or something but if at the end of a level you could force a big chunk to cache manually it wouldn't be so bad.

J(ohn)