About mtune=atom

Bill Nottingham notting at redhat.com
Mon Jan 24 17:55:59 UTC 2011

Jakub Jelinek (jakub at redhat.com) said: 
> On Mon, Jan 24, 2011 at 09:25:45AM -0800, John Reiser wrote:
> > Actually many of them should be using the new x86_32 software architecture,
> > which is the 64-bit instruction set (thus 16 "general" registers, SSE, ...)
> > but with integers, longs, and pointers all 32 bits.  The upper 32 bits
> > of any user address are 0, and not stored in RAM (except the return address
> > of CALL.)  This gives a measurable benefit on boxes with low RAM.
> Except that such a model is only barely supported in binutils, the support
> for it in gcc is pre-alpha state on a branch and there is no kernel nor
> glibc support.

Am I missing something, or would this also be binary-incompatible? If so,
that's very very very much not worth the effort.


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