F13 glibc with nopl instructions - an explanation

Daniel Drake dsd at laptop.org
Tue Jun 8 18:33:22 EDT 2010


In the FESCO meeting today
Fedora developers and some members of the OLPC community discussed the
loss of Geode LX (i.e. XO-1) support in F13.

It looks like we are all in agreement that the loss of support was
unintentional, but we postponed making a decision on the solution
because we realise that we don't fully understand the issue. The only
package we can see that uses nopl instructions is glibc -- why only
glibc? What changed to make that happen?

I've investigated and my explanation is here:

In a nutshell: glibc now is more agressive than most packages with its
optimizations, and takes an extra step to communicate the desired
processor optimizations to the assembler. (CPU-specific optimizations
in other packages are limited to the compiler and linker)

What are the next steps? Do we take this back to FESCO? When is the
next meeting?


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