Comment by SomeHacker44
5 months ago
Silly question. Are there any 486-compatible small CPUs that could be embedded into a project instead of using an FPGA? Given that AMD, Intel and others have the ability to make 486-compatible processors currently, I would have thought you could just buy a CPU or SoC to run 486 code.
Define "486-compatible." As far as I know even intel's newest cpus can run 486 era 16-bit stuff in hardware.
But, a plain answer: Via Eden boards. still use north/southbridge architecture, and are from the mid 2000's.
It's just modern Windows/Linux that have discontinued the ability. Or, perhaps you have 16/32 and 32/64 and are unable to do 16bit on 64bit machines- which still boils down to "operating system."
By far the biggest issue though is that even the Via Eden processor is significantly faster than a 486- and lots of software (especially games) from that era used no-op instruction loops for timing and timers. This results in games like The Incredible Machine's level timer running out in half a second or less.
In Windows, once you're in long mode, there's no 16-bit available to you. You can instead take the DOSBox or other VM route.
Linux isn't really relevant given the time frame.
I left it open as to if it was a hardware or OS level item that prevents 16bit. Because I don't know, and don't care to dig that rabbit hole.
Also- DOSBox is an emulator vs VMs are hardware, no? I suspect A VM won't fix the "no-op loop for timing" issue- with modern processors' lowest clock being 600-800Mhz before it gets C6/C7'd, 30 years of IPC improvement, and the possibility of the CPU itself optimizing such loops (I'm unsure for various reasons): I expect the UX of "just limit how many scheduler slices it gets" to be nasty.
1 reply →
Intel did have a product like that but it's been discontinued: https://en.wikipedia.org/wiki/Intel_Quark
AMD even had two of them. Their own: https://en.wikipedia.org/wiki/AMD_%C3%89lan and based on the Cyrix x586 after they acquired them: https://en.wikipedia.org/wiki/Geode_(processor)
They weren't even that bad considering the little power they needed.
Vortex86 is probably the closest thing to what you are looking for.
Any idea when Pixel86 is going to be available again or how/where to get an ITX-Llama system?
Pre-orders:
https://retrodreams.ca/
Review - https://www.youtube.com/watch?v=L9UdU89DDvY
3 replies →
There used to be single-chip x86 systems, but I don't know if they went all the way up to 486. You'd see them in early low power portables.
I'm guessing the ITX-Llama is far less affordable next to reusing a "generic" FPGA retrogaming board.
There is a branch of Via (?) in china making enhanced 486 system on a chip "586" systems. I'm on mobile so I don't have the name handy but I'm still hopeful these get cheap enough to enter the hobby space more.