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Re: i486 base architecture



On Tue, 2004-11-30 at 12:05 -0500, William M. Quarles wrote:
> performance difference.  Now were you saying that this cmov is part of 
> i486 or i686?

i686

> Would I have to worry about any trademark problems?

?????



> Is there a script that Red Hat uses to automate the build process?  Does 
> it use SRPMS or do the sources and specs have to be "preinstalled?"

srpms; what you can do yourself is install most of the rpms (so that all
buildrequires are met), then get the src.rpm's in one dir and do

for i in *.src.rpm ; do rpmbuild --rebuild --target i686 $i ; done

for a first cut approximation... takes 24 to 36 hours though.


> > However, newer ones (both AMD and Intel) operate in such a way that the
> > advantage of this no longer is an advantage, they need to know the
> > result anyway in effect (and also make a guess about the "if" result)
> 
> Is the advantage still there

not anymore

> , or is it just no longer a significant 
> advantage?  Or is it a cost?  Unless it's a cost, I don't see what's 

on newest P4 cores it seems to be a cost even (given that cmov can't do
all the addressing combinations normal mov can, gcc may have to add some
slight additional glue code which is a cost)

> wrong with putting in the advantage, unless it's a lot more work on your 
> part.  Is it more work?

it means that you don't run on cpus without cmov...


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