Re: Where is it written?

[Michael Meissner <meissner@spectacle-pond.org>]

On Sat, Nov 11, 2000 at 12:28:54PM +1100, Keith Owens wrote:
> On 10 Nov 2000 17:10:00 -0800, 
> "H. Peter Anvin" <hpa@zytor.com> wrote:
> >We can mess with the ABI, but it requires a wholescale rev of the
> >entire system.
> 
> AFAICT, there is nothing stopping us from redoing the kernel ABI to
> pass the first few parameters between kernel functions in registers.
> As long as the syscall interface is unchanged, that ABI change will
> only break binary modules (care_factor == 0).  The ABI type would need
> to be added to the symbol version prefix, trivial.

Other than the minor little fact that -mregparm=n exposes several latent
compiler bugs, that since it is not part of the ABI, it isn't on anybody's
radar screen as needing to be fixed.  This is of course the downside of free
software, that volunteers tend to have their own ideas of what to work on.

Also note, that for -mregpar=n, it is important that variable argument
functions be declared properly in all callers, since they need to use the
standard calling sequence.

-- 
Michael Meissner, Red Hat, Inc.
PMB 198, 174 Littleton Road #3, Westford, Massachusetts 01886, USA
Work:	  meissner@redhat.com		phone: +1 978-486-9304
Non-work: meissner@spectacle-pond.org	fax:   +1 978-692-4482
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