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Re: Software for the IBM PC Light Pen?

in PC Emulation
^ Interesting... nice to know! I'm positive that I encountered an obscure free/shareware/PD game from the early 1980s which had the option for light pen input; it was a simple game that ran in text mode - a "row swap" puzzle thing IIRC. I know that doesn't help much, but I'm out of town and won't be …

Re: PCEM Hercules

in PC Emulation
I can't see any additional brightness levels there... PCem was probably showing true 1-bit Hercules video, or at least I assume so. But the screenshots show 'in-between' levels where there should be sharp boundaries, and XnView reports somewhat more than 2 unique colors: herc1.png herc2.png It's …

Re: PCEM Hercules

in PC Emulation
Last time I checked, PCem didn't magically expand the HGC's capabilities to support more brightness levels than just "pixel on/pixel off"... is this some shader? Or just a really good Hercules card? 😀

Re: MartyPC

in PC Emulation
That's not quite what it did, it ticked the device without ticking the CPU. It was pretty specifically built for debugging the end credits of area 5150. It might be back at some point, but my CGA optimizations broke it. Alright, then consider my wrong impression of what it did to be a feature …

Re: MartyPC

in PC Emulation
Will the "device control" debug tool be back in some fashion? Looking through the commits tells me it was considered unstable and hidden behind a 'devtools' build config option. As I seem to recall, it allowed you to step through execution in multiples of PIT/CGA/etc ticks... at least I assumed …

Re: A very early CGA card?

Yeah, it's hard to tell based on the date codes alone - they probably mixed-and-matched components from whatever batches they had lying around (U33 is the character ROM). Mid-'82 sounds about right, and my card also has that '8212' text on the back, but the narrow XT-type bracket must have come …

Re: A very early CGA card?

I have one like that. Same P/N, wiring job, and resistor count/values at the composite output stage (one less resistor than other known 'early-type' CGA boards... although I don't think there's much of a difference in the output). However mine has the later, narrower XT-type bracket: 1804464-front+ …

Re: Old keyboards

Model F capacitive buckling spring board with modern minimalist 84-key SSK layout, made with the original tooling brought out of retirement. Is that from https://www.modelfkeyboards.com/? I had no idea that the original Model F tooling was involved. I was pleased to see that they finally introduced …

Re: MartyPC

in PC Emulation
I am thinking about a software frontend in the future for lower-spec machines, but you won't have the debugger. Ah, then no chance for a simpler console/TUI-based debugger interface? I was wondering if that could make things easier to implement, maybe through one of those curses libraries that can …

Re: Emulating CGA Snow

in PC Emulation
So in VGA terms, basically the value read from plane 1 (the attribute plane) gets replaced with the value that's read from RAM, while the other byte (from plane 0, which is the character byte) gets read normally? On these particular cycles yes, that seems to be what's happening. The alternate case …

Re: Emulating CGA Snow

in PC Emulation
Oh, missed this: I surmise that the character bytes for the displayed text in video memory being copied generate the initial variety of different colors within the snow immediately below; after we proceed past that the snow becomes either white or green. I am not sure where the green comes from. The …

Re: Emulating CGA Snow

in PC Emulation
Parts like the intro, the dot starfield, the Delorean, and the IBM vectorballs should have absolutely no snow, since they're not running in 80-column (+HRES) mode.

Re: MartyPC

in PC Emulation
That also works for the PCjr and Tandy 1000, which happen to have 90-degree-increment shifts (relative to the IBM CGA) in mode 6. Is that all that is needed? I would have thought there would be some differences in the multiplexer, too... There could very well be - to get that figured out, we'd need …

Re: MartyPC

in PC Emulation
You can roll the hue through 360 degrees and nothing looks quite right. Somehow a phase adjustment is intrinsically different, but I haven't worked out the math as to why. I think I get it, now that I've had a look at v0.1.3. I must've misconstrued which part of the signal processing chain this …

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