Michael Schnell wrote: > Jamie Lokier wrote: > > > > compare_exchange is a single architecture-specific instruction; that's > > what we're discussing. > > Not really. The OP is working with Microblaze, I am working with NIOS2. > Both archs do not have any provision for atomic memory modification at > all, so we need to implement it by some pure software tricks (i.e. > special provisions in the general ISR entry code) or by implementing a > dedicated custom instruction.
Sorry, the topic wandered a bit, and *I* was talking about the relative merits of atomic compare-exchange versus atomic read-modify-write instruction... :-) The general principle also applies to a custom instruction operating on special registers - avoid spinning to implement the 'atomic' part, and don't confuse that with spinning on a lock. But it's not that significant in the scheme of things. -- Jamie _______________________________________________ uClinux-dev mailing list uClinux-dev@uclinux.org http://mailman.uclinux.org/mailman/listinfo/uclinux-dev This message was resent by uclinux-dev@uclinux.org To unsubscribe see: http://mailman.uclinux.org/mailman/options/uclinux-dev