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Corner cases with the 765 appear frequently but the only major problem I know of currently is DD 5.25 disks in HD drives.

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Well. That sure was a whole thing.

Time to clean out all of the commented-out code, tighten up some of the functions, optimize it, pull-request it, flip it and reverse it.
[video:youtube]
[/video]

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[Linked Image from i.imgur.com]
Interestingly, if you implement more of the CRTC, it’s less likely to hang.

The vertical smearing is a feature – the so-called 1:2:1 convolution. In reality, it reduces interlace flicker. It’s only used for indexed colour modes (bandwidth between RAMDAC and VRAM is too low to support it in direct colour mode), and it’s only used when 1MB VRAM is installed (there doesn’t appear to be a technical reason for this, just to “encourage” you to buy the card with more VRAM).

Drawing in interlaced modes still isn’t quite right, most noticeably with the vertical offset. But this is all derived directly from parameters sent to the framebuffer controller, CRTC and RAMDAC – no magic numbers.

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More progress on the Psion MC400, the machine is running and has working keyboard.
[Linked Image from i.imgur.com]
The System folder is empty as I now need to emulate another ASIC that communicates with the Solid State Disks. I have an image of the System Disk containing the apps, just need to work out how it's accessed.


BBC Model B, ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, etc.
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"The vertical smearing is a feature "

US patent 5097257

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PS/2 Model 80 is now happily booting DOS and the reference disk after some DMA fixes.

[Linked Image from i.imgur.com]

[Linked Image from i.imgur.com]

It doesn't do anything with the reference disk because MCA emulation is nonexistent at the moment but DOS runs fine.

Last edited by Luigi30; 07/06/22 03:17 AM.
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Originally Posted by Revenant
Further adventures in 90s Casio MIDI gear:


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And finally, 10 minutes of demos from the Celviano AP-10 piano: https://revenant1.net/casio/ap10_demos.ogg (no DSP this time either)

I'll need to make a layout for this one, since it doesn't have a screen.

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Real hardware reference here:


With the caveat that this is a microphone recording rather than direct, the DSP isn't really doing much, there's just a little reverb.

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It's the same DSP as on the CTK-601 and others, with a similar set of 3 presets. It's definitely much more noticeable with the "stage" and "hall" presets on the 601 (like in this recording for example).

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