MiSTer FPGA Forum

Somebody has modded XP so it works on the 486.
https://www.techspot.com/news/103067-wi ... hanks.html

Has anybody tried this on ao486?

Yup, I did.

@kconger brought it up to me this https://msfn.org/board/topic/186080-xp- ... a-486-cpu/ a week or so ago
My firsts tests on ao486 lead to bsod during installation. Managed a full install within x86Box, but it will not boot under ao486 stating "NTLDR missing" and another file missing error (the files are there, for sure another issue).

@thera34 did you see this install note?
NOTE: After the installation is finished, you must copy ntoskrnl.exe from the ISO to C:\Windows\System32, or else the OS will be unable to boot.

Yes, I followed them precisely, waiting hours to install, copying those files over , first with the German ISO, then the English one (picked from forum posts) but no dice
(yet)

Hmm, is it a driver issue? Windows 95 crashes on boot in a similar way until you remove the storage drivers.

Windows 98 and newer require an x87 math coprocessor, which ao486 lacks due to the 486 core already taking up nearly the entire FPGA.
Windows 2000 and newer require instructions that were introduced with the Pentium, which also features an on-die FPU.

I've heard of people getting Windows 98 working on MiSTer with a software FPU emulator TSR, but that approach is impossible on anything NT-based.

Also, if you've ever tried to run XP on the minimum spec of a Pentium MMX 233, it's almost unusable, no matter how much RAM you throw at it.

The Ao486 actually runs great on the Mister, I've been using W98 on the Mister for more than a couple of years, never had any major issu and you don't need an FPU emulator either (it's to allow some extra games to run). Lu made very nice tutorials for that, so it's definitely not impossible and you can get many native win98 games to run. ( you just have to keep your expectation in check.)