Francis Galiegue wrote:
>
> On Fri, 25 Aug 2000, Antony Suter wrote:
>
> >
> > I think that this is in error. I understand from gcc 2.95 documentation that
> > only one of the flags -m, -mcpu and -march need be specified.
> >
> > My understanding is that:-
> > "-mcpu=pentium" specifies to optimise for the pentium but allow to run on
> > other cpus.
> > "-march=pentium" specifies to optimise fully for the pentium, dropping
> > compatibility for other cpus.
> >
>
> That's it. The cpu= stuff provides optimal instruction ordering for
> Pentiums (note that this same order differs for PPro and upper!) whereas the
> arch= introduces arch specific instructions.
>
> > I think that it is non optimal to specify both -mcpu and -march at the same
> > time.
>
> Well, it is - for Pentiums. Ppros run fine with it too, at least faster than
> without any of these. I don't know what the -mpentium is for.
I am still not sure what is optimal (when im compiling only for my own
machine).
It is best to specify both -mcpu=pentiumpro and -march=pentiumpro for my
Pentium III machine?
> Oh, one last thing: using fast-math is tricky, especially for apps expecting
> full IEEE compliance. Try at all possible NOT to use it.
Its a standard option for cross compiling the kernel in mdk 7.1 (im not sure
about cooker).
All the mandrake kernels ive seen, in source code form, specify all three of
-m, -mcpu and -march. Also the kernels specify them multiple times in
different places with multiple instances of other flags as well. So the
kernel ends up with long redundant option strings on the gcc compile line.
--
- Antony Suter ([EMAIL PROTECTED]) "Examiner" openpgp:71ADFC87
- "And how do you store the nuclear equivalent of the universal solvent?"
