Messages in this thread | | | From | "H. Peter Anvin" <> | Subject | Re: [Q] Looking for an emulation for CMOV* instructions. | Date | 11 Jan 2002 23:52:50 -0800 |
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Followup to: <p737kqpp60w.fsf@oldwotan.suse.de> By author: Andi Kleen <ak@suse.de> In newsgroup: linux.dev.kernel > > One corner case where emulation would IMHO make sense would be CMPXCHG8. > It would allow to do efficient inline mutexes in pthreads, and hit the > emulation only on 386/486. cpu feature flag checking is unfortunately > not an option normally for inline code. >
You don't need CMPXCHG8B to do efficient inline mutexes. In fact, the pthreads code for i386 uses the same mutexes the kernel does (LOCK INC based, I believe), complete with section hacking to make them efficiently inlinable -- and then they're put inside a function call. I believe "kill me now" is an appropriate response.
-hpa
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