AmigaOS 3.9 with a 68000 and 2MB

[Gulliver]

Food for thought:

Can AmigaOS 3.9 be tweaked to be used on a 68000? Even worst, can it work with just 2MB?

See my findings in the attached snapshot.

[XDelusion]

I was having the same thoughts just last night.

I'm pretty sure some of the bits and pieces of OS 3.9 are 020 (or better) dependent, but maybe there is a work around...

[AmigaHope]

I was having the same thoughts just last night.

I'm pretty sure some of the bits and pieces of OS 3.9 are 020 (or better) dependent, but maybe there is a work around...

There's a patch I remember seeing on Aminet that patched unimplemented instructions realtime to let you run 020/030 apps on the 000/010.

I tried it and it really did work! D=

[Gulliver]

Do you remember the name of that patch?

[Crumb]

Food for thought:

Can AmigaOS 3.9 be tweaked to be used on a 68000? Even worst, can it work with just 2MB?

See my findings in the attached snapshot.

It would be interesting if 020 instructions could be patched to plain 68000 to make Reaction work. On the other hand I would keep 3.1 prefs instead of 3.9 when possible (being able to access them without romupdate or reaction is useful)

The most interesting parts of 3.9 are the updated scsi.device, FFS, wb/icon libraries (due to WB shortcuts and possibility of seeing glowicons although for 68000 I think MagicWB is faster). The rest is not as interesting IMHO. Use Toolsdaemon instead of AmiDock.

If PFS3 is released freely for 68000 I guess I won't miss SFS on plain 68000.

[ami_stuff]

Do you remember the name of that patch?

http://aminet.net/package/util/misc/Run68017

[kolla]

Interesting, got to try that :)
I'm not at the same location as my minimig right now, but in case anyone missed out... here (http://www.minimig.net/viewtopic.php?f=3&t=153) is what I did last august. Since then I upgraded to 4MB of RAM and buildt a custom kickstart with all 3.9 parts in it. I find that VinCEd eats too much for what it offers, so I use KingCON - one of my big gripes is that KingCON 1.8 with a patch to make it "romable" only exists for 020+ :)
(I use quotes, since it really cannot run from ROM (it writes to its own memory), it needs to be copied out to RAM first.)

[Gulliver]

I am torturing AmigaOS 3.9 thinking on the fpgaarcade board, the Minimig 4MB and the C-One with the minimig expansion. Maybe a 68000 user with a real Amiga can also benefit.

It would be cool to have them run 3.9

Thanks ami stuff, I am going to try that patch and see how it helps me achieve more functionality.

[Karlos]

There's a patch I remember seeing on Aminet that patched unimplemented instructions realtime to let you run 020/030 apps on the 000/010.

I tried it and it really did work! D=

How does it cope with, for example, 020+ addressing modes?

Suppose you had:

add.l (a0,d0.l*4), d1

...which, as far as I know takes up exactly the same space as the vanilla 68000:

add.l (a0, d0), d1

...is there even room in the instruction stream to replace this with a jsr to a routine that can handle the scaled index mode?

[mongo]

How does it cope with, for example, 020+ addressing modes?


It doesn't.

[kolla]

OK, here (http://amiga.nvg.org/moro/minimig/) you find the minikick.rom I use with my minimig. I did not see anything in the boingball4 that should end up in a kickstart anyways :)

http://amiga.nvg.org/moro/minimig/minimig-2010-05-17.png

[matthey]

It doesn't.

Then it's worthless. The scaling is ignored on the 68000 with no exception. It would crash most of the time later on. The 68k instruction set is designed to be forward compatible but not backward.

There is also the issue of non-byte memory accesses on the 68000. An exception handler can catch this and do the access correctly but it is slow.

We need 68020+ fpgas with AGA+. That's what I'm waiting for.

[Gulliver]

Thanks kolla! I am using it right now :)