i386 Multilib Options

[Joel Sherrill]

Hi,

I don't think we have looked at multilib options
for the i386 in a while.  Should the set be adjusted?
I currently see

./libc.a
./soft-float/libc.a
./mpentiumpro/libc.a
./mpentium/libc.a
./m486/libc.a
./m486/soft-float/libc.a

We have previously agreed that soft-float is
important and leaned to keeping the i386.

The i486 class is a distinct improvement on
that but I don't know if it really is worth
a multilib.  Any true instruction or tuning
differences?

That leaves us with pentium and pentiumpro.
Are these the best selections?  Worth keeping?

Should we switch from -mtune to -march?  Does
this buy any performance improvements.

We have pc386 variants with SSE enabled.  Is this
enough?  Do we need MMX or SSE2/3 BSPs.  Does this
require something in RTEMS?

Just trying to take a lay of the land from the
community's perspective and derive some requirements.

Thanks.

-- 
Joel Sherrill, Ph.D.             Director of Research&  Development
joel.sherrill at OARcorp.com        On-Line Applications Research
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