Re: PowerPC E500 port

[Roland McGrath <roland at redhat dot com>]

The glibc norm is that host triplet and --with-fp setting are what specify
the ABI the glibc build will support.  The --with-cpu setting affects what
hardware the glibc being built can run on, but it may not affect the ABI.
The powerpc32 soft-float ABI is indicated by powerpc-*-linux --without-fp.
If powerpc-*-linux --with-cpu=e500 will produce that ABI, it must be
synonymous with powerpc-*-linux --without-fp --with-cpu=e500.  

The sysdeps/ subdirectory layout is an internal implementation matter.
It's nice when the names are intuitive off the cuff, but that's not really
what they're there for.  The configure machinery drives it in a certain
way, and given that algorithm we organize things as works best to share code.

To avoid accidental misconfigurations, sysdeps/powerpc/preconfigure should do:

	test "x$with_cpu" = xe500 && with_fp=no

This means configure will check sysdeps/powerpc/powerpc32/e500 and
sysdeps/powerpc/powerpc32/e500/nofpu.  It doesn't matter whether you have
an FPU, that's just what the directory is going to be called for this
combination of configuration options.  If all E500s have always had FPU
hardware, then you can add sysdeps/powerpc/powerpc32/e500/Implies with:

	powerpc/powerpc32/e500/fpu
	powerpc/fpu

or whatever is appropriate.

Your use of soft-fp seems fine to me as far as organization.  Does that
interact correctly with sysdwps/powerpc/soft-fp/?


Thanks,
Roland