Adding new PowerPC platforms to the build

[Peter Grehan]

> There's at least 1 gotcha: I think the ABI for embedded space is
> different from server space (Book III-E vs Book III-S). Think
> floating-point. MI code that is intended to run on a Book III-S
> ISA processor should use hardware FP. MI code that is intended
> to run on a Book III-E ISA processor cannot.

  Sure.

> For example, the following seems quite user-friendly and intuitive:
>     make release TARGET_ARCH=powerpc TARGET=server
> or
>     make release TARGET_ARCH=powerpc TARGET=embedded
> 
> and it does solve the biggest problem we're facing. Would this be
> so bad?

  Perhaps a better distinction is a default value of 'server', and an 
override of TARGET=softfp since there are a large class of embedded PPC 
cpus that can do floating point.

> Also, I don't want to assume that whatever we do should be done in
> the same way as pc98 and sun4u has been done. I think they have set
> a bad example.

  Agreed 100%.

later,

Peter.