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OffTopic > [DS] An idea

#89727 - Dracker - Mon Jun 26, 2006 2:20 pm

I'm posting this in off topic because nI'm not sure if it's even possible.

I've managed to get a friend interested in the homebrew scene. But he asked some questions that really piqued my interest. I told him about moonshell, and he asked "Can you play mp3s while playing a game?"

My answer was initially a definite no, but this got me thinking. DS has 2 processors, and the ARM7 is the gba processor. In theory, could an ARM9-only DS app run, while a gba app or homebrew game is also running?

This also got me thinking of the limitations. The X, Y buttons, the touch screen, lid, and importantly in this scenario sound can only be handled by the ARM7 ... but the rest of the buttons would be used by the gba app.

While nearly useless (no input and only video output available to ds app, and an open source gba app could probably be converted to ds without too much trouble), it sure is interesting to think about. The DS is a mysterious and powerful device, whose mystery is only exceeded by its power.

#89775 - DekuTree64 - Mon Jun 26, 2006 5:59 pm

ARM9 and all the other non-GBA circuitry is shut off in GBA mode, so that's not possible. Homebrew on the other hand could be done, but the 2 apps would have to be coded to share resources.

Might be cool to make a multitasking operating system for the DS so apps could coexist more easily, but they'd all have to be pretty light on memory considering there's only 4MB available. Either that or have them save their current state on whatever storage device using FAT lib when going inactive, so they can free up most of the memory. Like if you have a web browser, text editor, image editor, etc. going at the same time. A music player would have to keep everything loaded though.
_________________
___________
The best optimization is to do nothing at all.
Therefore a fully optimized program doesn't exist.
-Deku

#89779 - Dracker - Mon Jun 26, 2006 6:12 pm

Doesn't Supercard run GBA apps without turning the DS-specific hardware off? I don't own one, but I heard (from am unreliable source) that this is one of the reasons for Supercard's poor battery life.

#89875 - PhoenixSoft - Tue Jun 27, 2006 3:07 am

Since Nintendo provides an ARM7 binary for all commercial DS games, would it not be possible to write a replacement for the ARM7 binary that includes extra functionality?