x86 boot code build

[Konstantin Belousov]

On Fri, Oct 05, 2012 at 10:04:26AM +0200, Dag-Erling Sm??rgrav wrote:
> Garrett Cooper <yanegomi at gmail.com> writes:
> > I would target the appropriate architecture (amd64) where it matters
> > (amd64), and target the lowest sane common denominator on i386. In
> > reality, what does a couple MB mean on amd64 vs i386?
> 
> 1) Nobody mentioned amd64 - this is about i386.
> 
> 2) It's not a question of *size* but of *performance*.  By targeting the
>    least capable platform that our users are likely to encounter
>    (pentium-mmx) instead of one which is virtually eradicated (486), we
>    can use features that are available on the former but not the latter.
So what ISA additions do you expect to get advantage of by switching
to pentium-mmx from 486 ? As I already said, I am not aware of any.

I can only think of cmpxchg8b, which would eventually allow to implement
64bit atomics on i386, but this has nothing to do with the compiler.
> 
>    Someone said they'd like to target SSE2, but that would leave many
>    common embedded systems out in the cold.  If we do that, we should
>    provide two sets of binaries; one set for sse2-capable machines
>    (which covers all i386 desktop and server machines made in the last
>    ten years) and one set for pentium-mmx (which covers the soekris and
>    other popular SFF / embedded systems).
> 
> DES
> -- 
> Dag-Erling Sm??rgrav - des at des.no
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