MIPS sign extension of addresses

[Fred Fish]

>  Well, that seems the reason of the trouble -- for MIPS addresses in
> object and executable files should be treated as signed and bfd_vma should
> be a signed type since that's how MIPS works. 

So does that mean that it would be more desirable if the MIPS ports used
signed long long for bfd_vma/CORE_ADDR instead of unsigned long long?

I'm willing to work on making that happen if that is the consensus for
making MIPS support more consistent with how the hardware works.

I've not yet checked, but are there fundamental reasons why bfd_vma
or CORE_ADDR have to be unsigned?

-Fred