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by Teknoman117 1612 days ago
Another one of my silly retro computing projects: https://github.com/teknoman117/m68k-fpga-bridge. I wanted to try and make an MMU for it, hence the 68010 specifically (which added some additional data to the bus error exception to allow restarting the failed instruction).

I also managed to get someone on utsource to sell me a tray of 386EX33s for like $2 a pop so eventually I can make some 386 systems. I managed to track down a few of the old IIT 3C87 FPUs that had the hardware matrix by vector multiply so I'm going to try to make some 3D renderer if I ever get around to putting it together.
1 comments
AutumnMeowMeow 1612 days ago
These are so cool! :-)

I like retrocomputing too, but more virtually: https://jexer.sourceforge.io/evolution.html

I wanted to make a cycle-accurate 286 system once, just because it was such an interesting architecture. Protected mode, but 16 bit, and 16MB max RAM, but with segment:offset addressing. What's not to love about all of that?

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Teknoman117 1612 days ago
Hardware multitasking and context switch on interrupt as well.

Admittedly I didn't live through that time period, but reading about them, they are quite interesting. It seems that the main reason they were considered "brain-dead" was because you couldn't run 8086 native and 286 native software at the same time, and backwards compatibility and interoperability started becoming something people considered very important.

Interesting enough that I went and bought a static core 286 (the 25 MHz Harris one) to play with. Since it's a static core I can run it at whatever frequency I want, even if that is only a few hertz.

https://imgur.com/gallery/LKAh7fB https://gist.github.com/teknoman117/342b43db8b79652c1c91e78e...

Things to keep me sane during the pandemic isolation :)

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