[hatari-devel] Falcon emu issues

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Hi,

This is just a brief reminder of a few of the Falcon emulation woes which likely still persist in Hatari. Oh to be the bringer of bad news :) Fortunately it's not a huge list!

1) The DSP measures a healthy ~57MHz last time I looked (Prior to UAE upgrades it did measure 32.000MHz exactly, spanning a long period of changes). This is not a showstopper but it's disconcerting and for me at least, I have to recheck everything more often on HW because of the speed gulf.

2) The Codec/host sync I think is still quite broken. Crunchy crunchy clickety click! There's an old thread on this topic from last year (?) which contains some of the info needed....

3) The display registers adopt ST behaviour, instead of Falcon behaviour, causing the backbuffer to be displayed instead of the frontbuffer if the display regs are written in the VBL. In a lot of cases you can work around it by 'just not doing that' but in some cases its not a straightforward workaround.


Not a big list. But I think these are all important enough to merit some attention before future major releases because they have non-obvious side effects on lots of code - especially the audio one, which can mislead new listeners into assuming the program/demo/game has badly coded music/sfx, or that the f030 just has bad audio generally!

(apologies if some or all have actually been fixed and I missed it!)


There is one potential DSP emu bug which I ran into recently and had to work around (at some performance cost) but TBH I need to confirm it is truly a bug first. I'll try to do the HW test very soon and report...

I noticed one separate thing on OSX - not Falcon specific - with the latest Hatari (albeit, maybe not *just* the latest version - I haven't tried an OSX version in ages!). It seems windowed mode results in aggressive slowdown and frameskipping, particularly if the host mouse is moved. In fullscreen, everything flies and behaves well. 

This problem was particularly evident while running a YM tracker prog (emulating STE), where the music replay would completely break up if you just move the mouse a little bit.

Cheers,
D.



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