Re: [Qemu-devel] [RFC][PATCH 000/111] QEMU m68k core additions

[François Revol]

Le 19/08/2011 04:14, Natalia Portillo a écrit :
> Hi,

[...]
(no need to quote the full thread!)

> > > He worked on emulating an abandoned, strange, difficult to get, and 
> > > undocumented hardware, using your 111 patches, and finished it before the wholy 
> > > more experienced MESS team.
> >
> > The next-cube emulation is really working ?
>
> Yes, it is, absolutely.

Cool I need to add this target to my Haiku port... where are the docs 
for the boot process ?


> > > > > Why are you planning to port a hack instead of making a full machine
> > > > > emulation?
> > > >
> > > > Because I'm lazy and dumb: the work is already done, I like cut'n'paste.
> > >
> > > Yeah, you said it!
> > > The work is already done, we have all the hardware emulation that Basilisk 
> > > substitutes for hacks.
> >
> > I'm not sure of that... no MMU emulation, no Nubus, no ethernet card, no
> > video card, no SWIM, no SCSI, ... useless with a patched ROM.
>
> Macs do not have videocards :p, only the Mac II and we're not forced to emulate 
> that one.
> SWIM is a piece of cake that can be even implemented without ICs, just some 
> logical arrays.
> NuBus is not required for almost anything, only the video card uses it, and 
> it's present only on the Mac II, a stub will suffice to make Toolbox be happy.
> Most m68k didn't include a network card, third party ones are stock chips 
> (probably almost all are NE2000, 3COM and PCNET), and Apple integrated ones are 
> also stock, easy to do :p

NIC isn't really necessary at first, those things don't netboot anyway, 
do they ?

> The MMU is your part I won't discuss on it.

There is 040 mmu support in ARAnyM (Atari Running on Any Machine), 
enough to run Linux, that has been backported to UAE (ARAnyM is based on 
the UAE core), that should give some hints:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=201442
http://www.amigaemulator.org/patches
http://www.amigaemulator.org/bin/patches/mmu/uae-0.8.20.2-mmu.diff.gz
(though I fixed a bug in handling TTR1 in ARAnyM)

It's why I chose to go Falcon first and use ARAnyM for the 68k Haiku port.

The 030 or 68551 ones are much more complex though (the 040 one has a 
fixed table layout, others have fully configurable table size for all 
the 4 levels). The 060 one is just the 040 with some cache restrictions.

> I know it's not perfect, but right now, it's better than nothing.
> There is no 68k cpu emulation complete afaik, I discussed with Ray Arachelian a 
> lot on that when he was working on LisaEm.
> However emulators are live, Aranym, UAE, LisaEm, BasiliskII.
>
> qemu-m68k is quite complete to go live (when it does not break mcoldfire) right 
> now.
> Bugs are easy to be corrected by more people when they are in main than in a 
> developer's own clone.
>
> Leave your little kid go wild, it's old and big enough :p

Release early, release often :p

François.