nommuenjoyer

Do I have to get Linux running on my SORD M68MX now?

(I actually planned to do this but unfortunately there seems to be a hardware issue and it seems to inside an irreplaceable ASIC :()

I followed you on github. I think you should be able to see my email address? If not the one on the 68000 fix commits in the kernel works :)

Do you only have a RAM expansion? If you have an MMU normal m68k linux will work for you. I have an a4000 running linux with an nvidia gpu ;) The drivers for the amiga filesystem etc all still work.

If you have the stock 020 we (me and the other people messing with this stuff) can make that work. the 68000 support needs one tiny thing, fixing the stack frame differences between the 000 and the 010+, and it'll boot on basically anything.

I already have patches to do it.

This is very cool. I thought literally no one else was using/interested in the 68000 support in the kernel. It was actually subtly broken for a long time. I think the fixes I did went in to 7.0 or 7.1..

I have some potential performance fixes for linuxmd like optimizing the multiplication that happens each time the kernel time infra needs to be updated. Would be cool to see if they help for you too and then get a "Tested-by" on the patch to mainline.

The 68000 isn't very fast to start with and: To get the code to fit into memory the kernel is compiled with -Os and GCC makes some poor inlining choices (keeping a call to a function that writes a value to an address in a register instead of just writing to the register, ~5 instructions vs 1), the Mega Drive only has vblank for interrupts, and so on.

Interesting.. I have some experience with the macintosh ROM from trying to fix up the EMILE bootloader for Linux (its boots like grub instead of being a macos app). Getting a recent GCC etc not to mess up calling stuff in the ROM was painful but QEMU emulates enough of the Quadra 800 that I could at least debug when registers were getting trashed etc with GDB. Alas, it still has some weird issues on real machines and randomly refuses to boot.

I'm going to do a u-boot port for the Mac at some point. It'll use the ROM to get loaded and then get rid of it. That'll work on nommu and mmu Macs and make the modern linux on Mac experience a bit nicer.

I plan to get this working on nommu mac at some point but I don't have one yet. I have a pile of 030/040 macs. Its not mentioned but this mc68000 kernel actually uses devicetree (like arm..) so its fairly portable.

In my QEMU fork there is support for a 68000 virt machine so you can have a multi-ghz emulated 68000 with 128MB RAM (maybe more, haven't tested) if you really want that.

And it really is on a MegaDrive as I only tested this stuff on a Japanese MegaDrive.