On Saturday 14 March 2009 23:11:07 Bill Hart wrote: > I think we should examine the feature flag in config.guess for > LAHF-SAHF. Here is an incomplete list of 64 bit Pentium 4's without > the feature: > > Pentium 4 506 E0 > Pentium 4 516 E0 > Pentium 4 511 E0 > Pentium 4 519K E0 > Pentium 4 HT 521 > Pentium 4 HT 531 > Pentium 4 HT 541 > Pentium 4 HT 551 > Pentium 4 HT 561 > Pentium 4 HT 571 > Pentium 4 HT 3.2F > Pentium 4 HT 3.4F > Pentium 4 HT 3.6F > Pentium 4 HT 3.8F > Pentium 4 HT 517 > Pentium 4 HT 524 > All Family 15, Model 4, steppings N0, R0 > Pentium 4 EE 3.73 > > Too messy to test for them all specially. > > Can we add a directory called LAHF to core2 and have all nocona > processors use only core2 in the build whereas specifically core2 > processors can use core2 and core2/lahf. It will be the simplest fix > for now until we can implement something more sophisticated. > Sounds good , give us 30 mins to do it
> Bill. > > 2009/3/14 Jason Moxham <ja...@njkfrudils.plus.com>: > > Early Intel CPUs with Intel 64 lacked LAHF and SAHF instructions > > available in AMD64 until introduction of Pentium 4 G1 step in December > > 2005. LAHF and SAHF are load and store instructions, respectively, for > > certain status flags. These instructions are used for virtualization and > > floating-point condition handling. > > > > > > I'll find out model numbers soon > > > > On Saturday 14 March 2009 17:20:25 Gonzalo Tornaria wrote: > >> On Sat, Mar 14, 2009 at 1:45 PM, Jason Moxham > >> <ja...@njkfrudils.plus.com> > > > > wrote: > >> > I pretty sure all core2 cpus have lahf,sahf , it's just some Pentium D > >> > dont have it . You can test the lahf_lm feature bit in cpuid to see if > >> > it's got it > >> > >> Tested in: > >> > >> My laptop: model 6 / family 15 (core 2 duo T5300). > >> My desktop is family 15 / model 6 (pentium D 930). > >> > >> The "lahf_lm" feature is present in both according to /proc/cpuinfo. > >> > >> Note that the laptop is "low end" core 2 (in the sense it has no VT > >> extensions). The pentium D is "high end" (in the sense it has VT > >> extensions --- low end would be pentium D 8xx). Maybe that makes a > >> difference? > >> > >> OTOH, the kvm 64 bit virtual cpu (kvm 72) doesn't seem to know about > >> the "lahf_lm" (meaning, it won't report it in cpuid, even if the host > >> processor has it. I assume the instructions would work anyway.) > >> > >> Gonzalo > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "mpir-devel" group. To post to this group, send email to mpir-devel@googlegroups.com To unsubscribe from this group, send email to mpir-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/mpir-devel?hl=en -~----------~----~----~----~------~----~------~--~---
