Re: [hatari-devel] Mame open sourced

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 05/03/2016 00:46, Eero Tamminen a écrit :
> Hi,
>
> MAME is now Free and Open Source Software:
>      http://mamedev.org/?p=422
>
> Has anybody looked whether Mame has any code that could
> be useful to share?  (IKBD, SCC?)

hi

that's good news. Mame has some interesting modular code, where each 
component has its own callback functions, which allow some kind of 
"plugging" between them.

For most components, I think Hatari already has more accurate emulation, 
as some undocumented behaviours are only visible under ST hardware where 
limits were really pushed by demo coders.

Also Mame code is C++, so not always easy to plug into Hatari which uses C.

I think Hatari has better 68000 emulation than Mame (both with old cpu 
core and even more with winuae cpu core), acia should be similar in both 
Hatari/Mame (emulation of the serial protocol), ym2149 has some 
interesting model regarding voltage / volume but I'm not sure this gives 
better sound that the table based model we use.

FDC is a complex part, Mame can deal with it at the flux/mfm level 
(similar to ipf/ctr) but Hatari already handles a big part of the FDC 
logic, it would be less work to add some PLL / bit decoder to Hatari 
than to import a whole new code.

ym2149 might have a better model of the period counting and square wave 
model, but it sometimes mixes ay-3-8910 and ym2149 references so it's 
not always clear to see if it's the exact behaviour of the ym2149. 
That's why I already planned to do some signal measure on my STF audio 
output and really documents the ym2149 behaviour in an ST.

Maybe hd6301 / ikbd could be used in Hatari, but here also we already 
have hd6301 emulation in Hatari that doesn't lack so many things to be 
complete (timers mainly).

I didn't check, but maybe there're some ACSI/SCSI code that could be 
reused in Hatari.

I'm a big fan of Mame since many many years, I think they have a very 
nice architecture, but I would say that "specialised" emulators like 
Hatari are more accurate in the end (using a smaller set of components).

Mame's code can also be a nice documentation, as components are often 
very faithful to the reference doc.


Nicolas