GBA Emu For DC (Visual Troy Advance) Continued

[curt_grymala]

Well, since the previous topic on this subject seems to be losing the first two or three posts on each new page, I decided to lock it, and start a new one. Please continue any discussions that were going on in the old topic.

BTW - Just for future reference, the original topic can be found at THIS LINK (http://www.dcemu.co.uk/cgi-bin/yabb/YaBB.pl?board=dcemu;action=display;num=1084378886)

[wraggster]

Cool

Troy do you want a load of pdroms collecting for a rom image when u release this emu.

one image with gba then another with GBC should be cool

[Cap'n 1time]

Isnt there some kind of gba dev contest? if it runs well on vta -visual troy advance (duh) you could release it with that and the runners up.

[alexp2_ad]

Hows this going then? Any news? ???

[Segata_Sanshiro]

Ok please hang on a sec, nobody else sees the lack of RAM as an important problem? (Sorry but I didn't read all the 9 pages of the previous thread)

[curt_grymala]

Ok please hang on a sec, nobody else sees the lack of RAM as an important problem? (Sorry but I didn't read all the 9 pages of the previous thread)

It is and it isn't an important problem. It has already been discussed, but here's a short breakdown:

This emu will not load any rom larger than 8 megabytes. However, there are quite a few commercial roms that weigh in at 8 megs or less.
In addition, I have never seen any homebrew GBA games that weigh in at more than 8 megs.

[Segata_Sanshiro]

OK thanks, I'll sleep better tonight ;D

[Hola]

And if the emu can cut some bloat out of it and get down to about 3mbs loaded then will be able to fit 12MB roms.

Another method i've been learning about is try loadin the emulator into the sound ram and use the other 16 for roms.

[Mekanaizer]

Hi

Or Troy can try to use the Dreamcast's ARM to help emulate the GBA CPU. I guess that this can be done, take the example of GEM a Game-Boy (B&W) emulator for the MSX.

http://www.tni.nl/products/gem.html
i thank you Patriek Lesparre for this GREAT GB emu for the MSX. THANKS

-Mekanaizer-

[GPF]

Yeah, the newest GBA emulator for GP32 is doing that, running most of the ARM code directly on the arm processor of the GP32.

I am not familiar with the ARM on the dreamcast, other than using the precompiled libs and even that is pretty limited.

I have had a lot more changes in my life in the last couple of days, so I probably will be away for awhile, except for when I am at work. But I will continue to work on the emulator as time allows.

Troy

[Alexvrb]

I don't think anyone has really figured out how to get decent speed from the ARM anyway. There have been some theories, but I've never seen anyone get it to perform as anything more than like a ~5Mhz ARM, if that.

Hola, you do realize that the bus to sound memory, even if you could get that to work, would be too slow if you needed to use the SH4. But I don't think that would work anyway? You could instead borrow memory from the sound/video RAM to store parts of a ROM, perhaps.

[quzar]

I don't think anyone has really figured out how to get decent speed from the ARM anyway. There have been some theories, but I've never seen anyone get it to perform as anything more than like a ~5Mhz ARM, if that.

Hola, you do realize that the bus to sound memory, even if you could get that to work, would be too slow if you needed to use the SH4. But I don't think that would work anyway? You could instead borrow memory from the sound/video RAM to store parts of a ROM, perhaps.

Its a 24Mhz ARM that is overclockable to 100, why would that be so slow? Also, everybody says the sound bus is super slow, but that is only relative to the rest of the hardware, what really matters is whether or not its faster than the GBA hardware.

[Cap'n 1time]

I don't think anyone has really figured out how to get decent speed from the ARM anyway. There have been some theories, but I've never seen anyone get it to perform as anything more than like a ~5Mhz ARM, if that.



your joking right? arm is some fast stuff... even i know that. and i dont know anything.

[quzar]

your joking right? arm is some fast stuff... even i know that. and i dont know anything.

He means getting the equivilant of 5Mhz out of the Dreamcast's ARM sound chip. The way that it is structured divides the effective clock speed down by a lot, because even though it works at 24Mhz, it can only be sent new data very slowly... or something like that.

[GPF]

plus the traffic for sound going back and forth across the bus would be competing for the resources.

[Alexvrb]

Quzar, you can't argue with me and against me at the same time buddy. It just confuses people. :P

Go ahead and compile something for the ARM in the AICA. The GBA's ARM is only clocked at 16Mhz, so you should at least get that kind of performance, right? *;D

Edit: I actually got a reply from Neill on the matter:

On Mon, 16 Aug 2004, Alex wrote:
> Do you happen to know what the ARM in the DC's AICA is (capable
of
> being?) clocked at?

2822400 Hz.

> Something about it sharing time with the rest of the sound
subsystem?

The effects DSP is only allowed access to main memory every other
cycle,
and it runs at 5644800 Hz (44100 * 128 ), so I guess the CPU gets the
other
half.


Neill

[quzar]

The arm is however software overclockable. you can send a command to it that will set the speed to anything between 1 and 100 Mhz

[GPF]

The arm is however software overclockable. you can send a command to it that will set the speed to anything between 1 and 100 Mhz

Any one know the command to do that?

[quzar]

ugh, i dont know it off the top of my head. I have seen it in some AICA documentation and i posted the excact thing over at DCemulation. Give me a bit and ill find it...


Whew, i finally found it...


according to "Yamaha AICA Sound System Hardware Reference v0.8" You can change the clock rate of the arm chip through the interrupt/timer register 0x28a8 which is set to the desired clock speed - 1. The examples this document give are 00 = 1Mhz and 24 = 25Mhz. Using this you could theoretically clock this higher, to 16 Mhz, 32 or probably even 64 without causing any permanent damage. I assume that what is happening is that it defaults to 3Mhz (~2.8) because that is the minimum required by the AICA but it is probably possible to go much higher than that (probably up to 25Mhz as sega notes) safely.

The speculatory parts of those are me.

You can find a HUGE post of info about the ARM by heliophobe here: http://www.dcemulation.com/phpBB/viewtopic.php?t=51558&postdays=0&postorder=asc&sta rt=200

along with that are my post in response, and some insightful randisms (read his first post after mine on that page hehe)

Edited to fix the quotes. YaBB doesn't handle quotes like phpBB, so you can't just enter a user's name with the quote (yet).

[tantasqua42]

is this project open source?

[Eric]

I think its a port of another emulator and if so it is open source

[wraggster]

Its a port of Chui`s port of Visual Boy Advance to the GP32 :)

Confused you will be ;)

[quzar]

its not really open source since it hasnt really been released yet, but when/if it is released it will be.

[Hola]

I lean more towards if at this point.

[quzar]

I lean more towards if at this point.

we don't care. quit trolling.

[Hola]

Yes your post as just as usefull quzar ::)

[quzar]

yes it conveyed a message to you that might be helpful to these forums.

[Alexvrb]

Hola, you do need to start showing a little restraint on the boards. That's all I'm saying.

[LyonHrt]

Sort your selves out guys, don't turn this into some argument, and please post useful posts, something that will contribute to the particular topic.

[wraggster]

Any news updates GPF?

[GPF]

no updates, haven't been looking at it for awhile.

I haven't had access to my dreamcast for awhile now, since I have had a lot of unexpected changes in my life lately.

Troy

[dice]

I hope it's nothing too serious GPF and I wish you many happy days

[Cap'n 1time]

Take the time you need. However long it takes, make it the very best.

[wraggster]

yeah i hope its nothing serious too.

[GPF]

Its going good, its just in the last Month I have gone from 1 kid to 3 kids. My older son 11 and daughter 13, just came to live with me, so my computer room is now my sons room, so I don't get anytime to program for the dreamcast anymore.

I get time at work occasionally and use Chankast. But the rest of the coding changes are things that I can't really test or evaluate in Chankast. Performance fixes and cd switching. I might have to releasing so that hopefully others can continue working on it. But I should be moving to a bigger place at the end of the year, so it might change then.

Troy