Re: [hatari-devel] Hatari FPU support

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Le 06/12/2020 à 21:42, Eero Tamminen a écrit :

On 12/5/20 6:11 PM, Jerome Vernet wrote:
Wich CPU/FPU combination are usable ?

Even thru the SDL GUI, I can select 68000/6882, Hatari ask to restart,
but no FPU is shown..

There is now way to have a 6882 with a 68000 ?

Hatari manual "The CPU Dialog" section says:
"The FPU settings are also only available with
the "WinUAE" builds of Hatari. They can be used
to select the type of floating point unit of CPUs
 >= 68020."

Looking back to old discussions on 68000 FPU
support, they apparently work very differently
and would be hard to emulate & undocumented.

* Thorsten: * Toni:

Nicolas, I think FPU should be listed in Hatari
manual HW matrix, but I'm not sure what notes
I should add for each machine type.  Any suggestions?


FPU line could be added to the matrix. 68881/82 can be used with 68020/030. With 68040/60, FPU is included in the cpu (but as these cpu were not natively used in atari's machine, it's not an issue for the HW matrix).

As christian wrote, 68000/10 can't use the 68881/82 directly ; note that Winuae's cpu core has a hack mode to use the FPU with 68000/10 anyway, but we don't use it in Hatari for now.

So, in the end, I think that FPU emulation should be marked as available i the matrix only for TT/Falcon (ie 68030 CPU). Other machines are using a 68000, so it should not be considered as possible (at least for Hatari at the moment, even if some HW modifications could be made, as described by Christian)


SDL, macOS & Python GUI should probably also note
that FPU selection is 020+ specific.

(And I guess I should move FPU accuracy note from
Features section to CPU dialog section.)

     - Eero

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