building i386 world on amd64 host: failed @svn

[Konstantin Belousov]

On Thu, Aug 15, 2013 at 09:12:52PM +0200, Dimitry Andric wrote:
> On Aug 15, 2013, at 20:36, Konstantin Belousov <kostikbel at gmail.com> wrote:
> > Does the linux box defaults to pentium or higher for -march ?
> > 64 bit atomics cannot be implemented in usermode on i386 on
> > processors which do not have cmpxchg8b instruction.
> 
> Ah yes, you are totally right, with -v it gives:
> 
>   COLLECT_GCC_OPTIONS='-O2' '-S' '-v' '-mtune=generic' '-march=i586'
> 
> So we should really disable atomics for i486 and lower?  Though I have
> understood that there also some pentiums without cmpxchg8b...

I do not think that there was any Pentium-branded CPU which did not
implemented cmpxchg8b.  Some late 486 did provided cpuid, but I am
almost certain that they did not have cmpxchg8b (cannot check anyway).
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 834 bytes
Desc: not available
URL: <http://lists.freebsd.org/pipermail/freebsd-current/attachments/20130815/90cd40df/attachment.sig>