[uae] Re: General questions about e-uae

  • From: Toni Wilen <twilen@xxxxxxxxxx>
  • To: uae@xxxxxxxxxxxxx
  • Date: Fri, 27 Jul 2007 00:00:21 +0300

3) Is there any MMU support yet? I want to try and install amiga port of
netbsd, googling the subject just takes me to posts that are
several years old saying there is an MMU patch.. surely by now its been
added?

E-UAE doesn't have an MMU emulation. I keep meaning to have a look at that patch you mentioned, but AFAICR it didn't work with the JIT, so it's not just a straight merge.

There is no MMU patch (and there really can't be) that is compatible with JIT (at least JIT-direct), also old UAE MMU patch is very incomplete (and unusable, for example no working bus error exception handling)

I think Aranym (Atari ST emulator) has the most complete 68040 MMU emulation but it isn't JIT compatible either (it uses UAE JIT)

Anyway, it uses some C++ exception tricks but should be possible to merge and it seems to be the best choice.

btw, MMU is very low priority feature, it is useless with 99.9% of Amiga programs (Linux/Unix/etc does not count, you can use other platforms to run those much better and faster), virtual memory is not needed under emulation and enforcer-like debugging stuff can be emulated without real MMU emulation and finally, CPU emulation speed will be quite unusable with MMU..

To be able to do anything useful with BSD or Linux (beyond booting a RAM disk), you'd also need emulation of some disk adapter hardware (for obvious reasons the current virutal filesystem and hardfiles won't work if you're not running AmigaOS in UAE). I know Toni's been working on a Gayle emulation (the Gayle implements the IDE interface on the 1200 and 4000), but I haven't merged this into E-UAE yet.

HDF IDE (A600/A1200 and A4000) and SCSI (A590/A2091, A3000, CDTV SCSI expansion) is emulated. IDE is very compatible, SCSI still has some compatibility issues with gururom, Commodore's drivers do work.

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