joerg at britannica.bec.de
Thu Apr 14 09:50:43 PDT 2005
On Thu, Apr 14, 2005 at 08:52:10AM -0700, Danial Thom wrote:
> --- "Martin P. Hellwig" <mhellwig at xxxxxxxxx>
> > As a stupid user I wonder what it takes
> > generally to support the AMD 64
> > bit extension, what are the typical issues in
> > supporting both 32 and 64
> > bit code? Links would be very welcome too :-)
It's another compatibility layer, which is a bit more difficult
since the pointer size changes and you effectively have to wrap
all system calls. There are other issues as well.
> A better question is what does it take to do it
> well, or whether its worthwhile. In FreeBSD, the
> amd64 is so clunky its unusable on a server, IMO.
> I shiver at the thought of trying linux, or
> windows, but I am curious. Is there a way with
> GCC 3+ to utilize the extra registers without
> running in full-blown 64bit mode? If you don't
> need the memory that seems like it might be an
> ideal enhancement.
No. If you really want to use 64bit, do it correctly. It's a
question of time when we do it, there are more pressing needs.
Also keep in mind that a lot of indirect changes are done in the
tree to get it 64bit clean without actually having 64bit architectures
to test. Think of the whole bus_dma support :)
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