Low Vector Support

Discussion in 'No$GBA Discussion' started by Gericom, Nov 13, 2016.

  1. Gericom

    Gericom New Member

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    Hi guys,

    Recently I've been working on GBARunner2, a gba hypervisor for the ds (run gba games from your slot 1 card), and it currently works quite well already with a couple of games. However, to improve the compatibility, it would be very nice if I could debug it, but currently that's impossible.

    To run the gba games, the gba bios is loaded in the first half of the itcm and the protection unit is configured to capture all accesses that are different on a ds from a gba. To make the gba bios actually work, the cp15 is used to switch to low vector mode, but no$gba doesn't seem to support that. It tries to use the high vectors (=ds bios), ruining everything. I also tried desmume, but even though it supports the low vectors, it doesn't emulate prefetch and data aborts, also a core part of GBARunner2.

    Anyway, it would be very nice if @nocash could implement low vectors, because it would probably help me a lot (and improve accuracy). Thanks on forehand.

    The source of GBARunner2 is here: https://github.com/Gericom/GBARunner2
    If you try it, make sure your card is fat32 formatted!
    ahezard likes this.
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  3. raystriker

    raystriker New Member

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    Would this help you? https://github.com/ichfly/gbaemu4DS

    It's a working hypervisor for the nds made by ichfly back in 2011, works with quite a few games. I really don't know much but if some of ichfly's code could help you make a great emulator, it's be great.
  4. Gericom

    Gericom New Member

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    I know of the existence of gbaemu4DS, mine is much cleaner and works better.
  5. raystriker

    raystriker New Member

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    That's cool, I intend to try it out. Was just wondering if ichfly's work could help you in the dev process
  6. Gericom

    Gericom New Member

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    If you follow the instructions on github, you should be able to build it.

    I can't deny that I compared his code to mine a couple of times, but most things are coded differently (and in assembly). It's also so that I first build the base of this from scratch, before I found out that gbaemu4ds works a bit as I had conceived.

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