On Wed, 2 Aug 2000, Warner Losh wrote:

> In message <200008021351.WAA17829@srapc342.sra.co.jp> Noriyuki Soda writes:
> : It seems that RM400 is a kind of arc platform, although currently it 
> : is not supported by NetBSD/arc.
> 
> The Linux/mips people support the RM400 (iirc, there are several
> models in this line and there are a few that aren't supported because
> they are MP and have oddities that aren't documented).  The systems
> have relativgely fast CPUs in them, iirc.  The only realy strange (I'd
> call it whacked out, but that doesn't translate well) thing that I can
> recall about these boxes is that they load the images 8 bytes higher
> than the headers of the ecoff.  The LILO loader that used to be used
> for Linux/mips had some code to cope with this very strange behavier
> (early in start: it will move the whole kernel down by 8 bytes if
> necessary).

So I wasn't going crazy after all!!!!   I struck exactly that problem
several weeks ago doing the NetBSD/mipsco work.  The problem turned out to
be the Mips ECOFF loader doesn't support more than 8 sections. If you
define more than that you smash the stack on the loader and it offsets the
address space.
The cause of the problem was the COMPAT_xx options in the NetBSD config
file were causeing a .bss section to be added.  If the ldscript was
changed to merge .bss and .sbss into a single .bss section the address
space loaded at the correct location.  At one stage I thought I had a
bunutils bug on my hands, but it wasn't.

> IIRC, there were several minor touch ups in the Linux kernel when
> support for this was introduced.  I've been looking for other arc
> machines than the one I have for a long time, and I've never even seen
> even a hint of one of these for sale in all the time I've looked.
> Several times I've been outbid on other machines, but I've not seen
> these.
> 
> I'd like to see NetBSD/arc support them.

The more machines the better :-)

Wayne
-- 
  _____	   	Wayne Knowles,  Systems Manager
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