Yet another architecture

[Ulrich Drepper]

schwidefsky@de.ibm.com writes:

> 1) The name of the beast. We use the preliminary name s390x at the moment.
> I can't say that I like it but I couldn't think of something better. The
> project name of the machine is "Freeway", the architecture extension is
> called "esame" and in addition s/390 has been renamed to zSeries. How
> should we call the configuration name for the 64 bit backend for S/390?

Well, so far we've added 64 to the names.  And 32 the old ones.
Means, something like

	S/390/64

> 2) How should we integrate this new backend to the glibc? Currently we have
> additional "s390x" directories in sysdeps and sysdeps/unix/sysv/linux. We
> started with copies from "s390" and modified them.  That differs in spirit
> from e.g. sparc who has two subfolders sparc32 and sparc64 in the main
> sparc directory. Any preferred method?

We should not invent new things.  It's already confusing enough.  I'd
suggest

- create sysdeps/s390/s390-32
         sysdeps/s390/s390-64

- move the files which cannot be shared from sysdeps/s390 to
  sysdeps/390/s390-32

Similarly of course for the Linux specific directory.

> 4) I defined a EM_S390X for the 64 bit binaries. Is there a way I could use
> EM_S390 plus an additional check for 64 bit in elf_machine_matches_host? At
> the moment elf_machine_matches_host only takes one parameter, couldn't we
> add the bit size?

I guess you could test for e_machine[EI_CLASS].  I'm not sure what
problems to expect down the road.  MIPS seems not to have a new EM_*
constant for their 64-bit architecture but everybody else does.

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