Question regarding GBA initialization

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Subv
Posts: 1
Joined: Thu Sep 04, 2014 2:20 am

Question regarding GBA initialization

Post by Subv » Thu Sep 04, 2014 2:32 am

Hello!
I'm relatively new to the homebrew scene, I've lately been coding a GBA emulator as a learning exercise and am using devKitARM as the compiler for my test programs, now, what i wanted to ask was regarding the initialization routine of the GBA hardware. As shown in this file: http://sourceforge.net/p/devkitpro/buil ... crt0.s#l71 the memory is cleared based on a condition and then copied from ROM, this is done by a loop of STMIA and LDMIA in Thumb mode. I've read that the GBA provides DMA hardware that can transfer data from memory locations at least twice as fast as the CPU can, is there any particular reason why it isn't being used here?

I'm sorry if the question sounds too dumb but I'm kind of new to all this.

Thanks!

elhobbs
Posts: 355
Joined: Thu Jul 02, 2009 1:19 pm

Re: Question regarding GBA initialization

Post by elhobbs » Wed Sep 10, 2014 7:27 pm

I want to say that dma is only faster for ram to vram copies whereas stmia/ldmia is faster for everything else... I may be thinking of the ds though.

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