| Re: [hatari-devel] Using the blitter for IDE transfers (Falcon emulation) |
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- To: hatari-devel@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [hatari-devel] Using the blitter for IDE transfers (Falcon emulation)
- From: Uwe Seimet <Uwe.Seimet@xxxxxxxxx>
- Date: Thu, 10 Jul 2025 14:16:31 +0200
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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
I only tested with the Falcon emulation, but I just also tested with the
MegaSTE emulation. I still do not see what I expect. My expectation is that
with the MegaSTE when using the blitter, the transfer rates are constant
regardless of the CPU speed. But when the CPU speed is higher, both the CPU
transfers and the blitter transfers are faster, and the blitter is always
faster than the CPU.
Best regards
Uwe