Re: [hatari-devel] Blitter emulation corner case

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On 09/05/2017 at 18:58, Christian Zietz wrote:
I think, Markus Fröschle inadvertently found a very weird Blitter behavior when doing single-word-per-line (XCOUNT=1) copies with FXSR and NFSR bits set.

I'm a bit lost here... What is the current status of that issue, in Hatari?

Concretely, I have just noticed a bug in EmuTOS, when drawing half-icons with Blitter. Maybe the same bug than Markus's one. The EmuTOS bug is visible on real hardware (and Steem), so it is definitely a real bug. But it is not visible in Hatari! So it seems that EmuTOS and Hatari makes the same wrong assumption, then the display is fine on Hatari... while it is bad on real hardware. Of course, both EmuTOS and Hatari needs fixing.

For memories, here is my bug report on the EmuTOS mailing list:

And see Steem screenshot as attachment, which is accurate to real hardware.

Software I use:
- latest Hatari from HG, freshly built for Windows/Cygwin.
- EmuTOS snapshot 20171201-235636-fae4158. Go to:
Download and extract etos512k.img.
This EmuTOS snapshot *contains* the EmuTOS bug, so it should be displayed as buggy, like the screenshot, but instead in current Hatari it displays fine.

Be sure to run Hatari in STe mode, and ensure that Blitter is On.

Instructions to reproduce the problem:
- Open a file window
- Maximize it
- Move it 32 pixels on the right
- See *good* disk and trash icon halves. They should be buggy, as they are on real hardware.

Vincent Rivière

Attachment: blitter.png
Description: PNG image

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