ABOUT THE GBA EMULATOR

**Eric** · August 17th, 2004, 18:05

Yeah i think Hola has the brains to work on projects. It seems he knows what he is talking about. If so Hola show GPF how to make his GBA emu. Im not joking.

Eric

**Hola** · August 17th, 2004, 19:50

Do you know how big of a hell coding for DC is? Its just so much easier to code for PS2 or Xbox. Xbox is just as easy as using a PC. I'm not saying SH4 is the end all to everything but asm is fast when it comes to console coding. I may seem like I always talk about of my ass but I do know some very reputable coders and I love to learn and enjoy there teachings.
I'm still trying to look into the theory of loading the emulator into the arm. All I keep hearing tho is that is should be theortically possable but I dont see how it would be.

**Kamjin** · August 17th, 2004, 21:14

Hola..
There's a few breeds of coder out there, I'm not going to say one is better than the other just one is different than the other. One comes from a Hardware background, and the other from a software background. The one's from a HW background instantly know how the arm in the DC can be used to execute code.

How to do it.. well exactly the same way you do vertex lists, or a fasion of "scatter gather" but in this case it's not scattering. Haven't looked at the arm specs on the DC much.. but this would be the basic idea..

first off the instruction set will have differnces, so you'll need some sort of translator/dynarec to handle the translation, and address remapping..
You have an imaginary map of the GBA on the SPU ram, the sh4 translates the instructions, and feeds them to the ARM, you'd sort the data by branches, and use the MMU to trap access outside the "chunk" then the sh4 would grab the data, and several pages ahead, and feed it back to the arm. when the "chunk" ends it will generate an interupt, and the sh4 will feed the next finished chunck to the ARM. (both possible paths of the branch were translated during execution time, so one is discarded and the other is fed)
During this time the SH4 handles the sniffing of the screen controller input etc..

**Hola** · August 17th, 2004, 21:20

That sounds like alot of effort to do. Would it even be worth doing just to load bigger roms?

**Kamjin** · August 17th, 2004, 21:42

There's a flaw with that.. sound.. you won't have much time left to do it, and not sure if the mmu can cover the arm that way..
By handling it that way the rom size doesn't really matter since you're only paging in sections at a time, and banking on the fact that you have alot of free time left from the parallel processing on the sh4 side to load etc.. but using this kind of approach will get it up to speed..

Is it worth it?? well I have a GBplayer, and a GBA + GBASP... so in my case.. not really..

***quzar*** · August 18th, 2004, 00:47

[quote author=Hola link=board=dcemu;num=1091059904;start=0#11 date=08/17/04 at 20:50:48]Do you know how big of a hell coding for DC is?[/quote]
yes. ;D

actually as long as you are doing purely software stuff it is simple. I have yet to have formal training of any sort in programming or computers (i took some courses in HS, but i basically ended up teaching them) and it's not that bad. I plan on learning bout hardware so that i can approach problems from either standpoint.

**milfzor** · September 26th, 2004, 00:42

and people were saying some months back that a neo geo cd emulator was unfathomable......... :

i've got faith in the guys doing the coding.....they have made some VERY nice projects.....

**Eric** · September 27th, 2004, 08:44

Yes but lets remember that every system has different chips and how these systems react with the different hardware can make a not possible emulator

**Alexvrb** · September 27th, 2004, 23:51

[quote author=Eric link=board=dcemu;num=1091059904;start=15#17 date=09/27/04 at 09:44:18]Yes but lets remember that every system has different chips and how these systems react with the different hardware can make a not possible emulator[/quote]I'm sorry my friend, you're in over your head.