[wbhart]

I've been using MartyPC for a few years and except for emulating glitches in hardware which depend on the manufacturer, date of manufacture or even temperature, it is getting harder to find cycle accurate tricks that MartyPC can't emulate perfectly (believe me, we've been trying).

The whole thing is a marvel of software engineering!

What is remarkable is that the author (GloriousCow) doesn't complain that people are ripping off his code and ideas, but that more people haven't used his learnings to create other cycle accurate emulators for the PC.

[johnklos]

Temperature? Really? How does that work?

[bonzini]

If you program a register at a moment and in a way that causes two signals to "collide", the result effectively depends on transistor behavior. That in turn can be temperature dependent.

For an example on the PC see https://int10h.org/blog/2023/03/cga-6845-crtc-phantom-vsync-...

[creatonez]

Thanks. Transistor level race conditions will keep me up at night.

[mrandish]

That was a fun rabbit hole. My first computer (8-bit, 4k RAM, 0.8 Mhz) had a video chip related to that 6845, the 6847, which was (sadly) a somewhat lower cost, less capable, less interesting chip.

[kaoD]

Amazing link. Thanks for sharing.

Where can I find more writeups like this?