Messages in this thread | | | Date | Mon, 30 Jun 2008 18:00:43 -0300 | From | Glauber Costa <> | Subject | Re: [PATCH 17/39] clobber rbx in putuser_64.S |
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Andi Kleen wrote: > Glauber Costa <gcosta@redhat.com> writes: > >> Instead of clobbering r8, clobber rbx, which is the i386 way. > > Note rbx is callee saved on 64bit, so using that one means > the surrounding function always has to save explicitely. > Not the case with r8. > > There's a reason it is the way it is. > > -Andi Right. Thanks for pointing this out. However, r8 is not available for i386. We could use %ax, but it holds part of the data for the call itself.
But for this case, I think we can come up with a macro that selects the appropriate register for each of them. Should be easy to do now that the code is merged.
Many thanks.
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