Re: [hatari-devel] Using the blitter for IDE transfers (Falcon emulation)

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 10/07/2025 à 12:52, Uwe Seimet a écrit :
> Hi,
>
> is the blitter emulation accurate in terms of speed? I am asking because
> with Hatari IDE transfers executed by the blitter (i.e. the blitter copies
> the data from/to the IDE data register) are much faster than with the CPU.
> Whether I am in fast-forward mode or not does not matter, the transfer rate
> is the same.
>
> On a real Falcon IDE transfers with the blitter are slower than with the
> CPU.

Hi

did you test only with falcon/68030 or also with megaste/68000 ?

because in all cases 68030 is not cycle accurate and ram access timings 
might not be correct either.

for 68000, blitter should be cycle accurate, it assumes 4 cycles per 
word access in standard RAM. If access to IDE registers are adding some 
wait states and take much than 4 cycles, then it's quite likely it's not 
correctly in Hatari at the moment.

But for the 68000 case it could be possible to improve this if we have 
some example timings from a real MegaSTE running at 8 MHz