| Re: [hatari-devel] MMU/SSW handling? |
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Sounds interesting! I'm still looking for improved CPU/MMU emulation for Previous (NeXT Computer emulator). That will be interesting for Hatari too.
There might be some news on this during the next weeks. I'll keep you up to date!
Am 08.12.2013 um 21:13 schrieb Eero Tamminen <oak@xxxxxxxxxxxxxx>:
> Hi,
>
> Is somebody still looking into MMU emulation?
>
> There's some discussion about NeoGEO emulator for Falcon:
> http://www.atari-forum.com/viewtopic.php?f=68&t=25780
>
> It would need several SSW register bits working correctly:
> --------
> The main and most important feature used by this emulator is the MMU and
> the "Bus Fault Recovery" capability (please refer to the "MC68030 User's
> Manual", Section 8.2) so you need at least a MC68030 or better. Actually
> this emulator will currently run only on a MC68030 because the MMU handling
> is different on the other CPUs.
>
> The MMU table is used to reproduce the NEO GEO memory map so that the game
> code runs in the original place (of course). The NEO GEO specific hardware
> registers are also mapped appropriately but they are marked as "invalid" MMU
> descriptors. Accessing those addresses will cause a bus error.
> ...
> The important SSW flags in use are: DF, RW and SIZE. The emulator routine
> clears the DF in order to emulate the functionality. For example in case of
> a read access (RW == 1) it writes the desired data value (of size SIZE) to
> the appropriate stack frame address and returns normally with RTE.
> --------
>
> That could be an interesting test-case for the MMU emulation. :-)
>
>
> - Eero
>
>