Re: [hatari-devel] Hatari state save/restore for Falcon emulation

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 22/09/2014 22:37, Eero Tamminen a écrit :
> Hi,
>
> WinUAE CPU core state save/restore was broken
> (for FPU), I fixed that and made the state handling
> a bit more robust.

Hi

thanks for the patch ; but is it really necessary to add a marker at the 
end of the snapshot ?

Overall, I think there're some limitations to our saving format when 
compared to other emulators, namely the fact that we often require to 
lost compatibilty with older snapshot version when a new version is 
released, instead maybe of loading the old version and filling the blank 
with default values.

For example, if we change something in the sound emulation, we should 
still be able to load the cpu, mfp, video, .... states as their format 
is unchanged.

So, we could have a snapshot format where each "component" is saved / 
restored as today, but with its own version. This way, we can skip 
unknown component (so maybe a 1.9 snapshot could be loaded with 1.8), or 
we could have some code in each component to be able to load an older 
section and fill the missing part with default values (when it makes sense).

This way, we could also keep previous snapshots and use them with more 
recent version of Hatari, which can be useful if you use snapshot to 
save some games' progress (this is something that is possible with 
WinUAE or Steem since years for example, and I think it's a good feature).

What do you think ?

Nicolas