Amiga.org

Operating System Specific Discussions => Amiga OS => Amiga OS -- Application questions and support => Topic started by: Gulliver on May 16, 2010, 07:12:17 AM

Title: AmigaOS 3.9 with a 68000 and 2MB
Post by: Gulliver on May 16, 2010, 07:12:17 AM
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.
Title: Re: AmigaOS 3.9 with a 68000 and 2MB
Post by: XDelusion on May 16, 2010, 07:27:27 AM
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...
Title: Re: AmigaOS 3.9 with a 68000 and 2MB
Post by: AmigaHope on May 16, 2010, 09:27:29 AM
Quote from: XDelusion;558777
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=
Title: Re: AmigaOS 3.9 with a 68000 and 2MB
Post by: Gulliver on May 16, 2010, 10:35:50 AM
Do you remember the name of that patch?
Title: Re: AmigaOS 3.9 with a 68000 and 2MB
Post by: Crumb on May 16, 2010, 12:10:48 PM
Quote from: Gulliver;558773
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.
Title: Re: AmigaOS 3.9 with a 68000 and 2MB
Post by: ami_stuff on May 16, 2010, 01:35:57 PM
Quote from: Gulliver;558795
Do you remember the name of that patch?


http://aminet.net/package/util/misc/Run68017
Title: Re: AmigaOS 3.9 with a 68000 and 2MB
Post by: kolla on May 16, 2010, 08:18:43 PM
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.)
Title: Re: AmigaOS 3.9 with a 68000 and 2MB
Post by: Gulliver on May 16, 2010, 10:05:44 PM
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.
Title: Re: AmigaOS 3.9 with a 68000 and 2MB
Post by: Karlos on May 16, 2010, 10:12:55 PM
Quote from: AmigaHope;558787
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?
Title: Re: AmigaOS 3.9 with a 68000 and 2MB
Post by: mongo on May 16, 2010, 10:15:48 PM
Quote from: Karlos;558914
How does it cope with, for example, 020+ addressing modes?


It doesn't.
Title: Re: AmigaOS 3.9 with a 68000 and 2MB
Post by: kolla on May 17, 2010, 01:44:44 AM
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)
Title: Re: AmigaOS 3.9 with a 68000 and 2MB
Post by: matthey on May 17, 2010, 02:14:21 AM
Quote from: mongo;558915
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.
Title: Re: AmigaOS 3.9 with a 68000 and 2MB
Post by: Gulliver on May 17, 2010, 05:05:47 AM
Thanks kolla! I am using it right now :)