On Wed, Mar 18, 2009 at 10:44 PM, Bill Hart <[email protected]> wrote: > Wait, how does it currently decide which ABI to use? Does configure > decide that aside from what config.guess says.
Yes, except config.guess may change it (but it shouldn't, as we discussed before this causes compilation failure, e.g. in a kvm virtual cpu which reports wrong cpuid). > I thought I recalled that this is why Gonzalo and I had nocona. The choice was made to match tuning options in gcc; from some gcc manpage, the options for p4 where "pentium4", "prescott" and "nocona", and the man page said "nocona" was for the p4 chips with 64 bit support --- iow, I assumed the "nocona" tuning option would be the only good one for 64 bit p4, but that may not be the case. Anyway, the point was, using the same name as gcc to avoid a mapping from cpu naming to gcc tuning options, but this is just another mapping which can be written, as long as the cpu names are fine-grained enough to get advantage of gcc tuning. e.g. calling "core2" a pentium D is not good, because -mtune=nocona gives better results than -mtune=core2 as shown by the benchmarks I posted in a different thread. Gonzalo --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "mpir-devel" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/mpir-devel?hl=en -~----------~----~----~----~------~----~------~--~---
