[hatari-devel] STF/STE using WinUAE CPU in prefetch mode

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Hi

up to now, the recommended cpu core to use for emulating STF/STE was the 
old UAE cpu core. It was tweaked over the years to support several 
complex features (instruction pairing, cycle precision for read/write 
when accessing video registers, exception stacks, ...)

But maintaining this is getting more and more time consuming, especially 
since we now use also the WinUAE cpu core, which has a much cleaner 
implementation of those features, handling them without all those 
hardcoded/specific cases.

As part of this transition, the last remaining differences were recently 
fixed and emulating STF/STE machines using WinUAE cpu core in "prefetch 
mode" should now give the same results as when using the old cpu core in 
"prefetch mode".

Could all people here test some of their favourite (or not !) STF/STE 
demos after compiling Hatari with "./configure --enable-winuae-cpu" and 
report any change when compared with old cpu core ?

Possible differences would be in cycle counting and precise cycles when 
accessing hardware registers, so you would see broken fullscreens, 
plasma effects with bad colors / shifted pixels or "spectrum 512" like 
images with mis-aligned pixels/colors.


Next step on the list is to use WinUAE cpu's "cycle exact" mode and 
update Hatari to use it in order to get precise bus accesses for each 
instructions, but this will take some time (for example, this would 
allow to remove hard coded pairing instructions)


Nicolas