Peter Jeremy wrote: [ ... ] > This was based on an examination of /usr/src/sys/*/include/atomic.h. > It looks like I was overly quick because the RISC architectures are > using compare-and-swap, rather than test-and-set primitives - sorry > about the error. The details are: [ ... ] > - ppc doesn't support 64-bit atomic operations lwarx/stwcx...? http://publibn.boulder.ibm.com/doc_link/en_US/a_doc_lib/aixassem/alangref/lwarx.htm http://www-128.ibm.com/developerworks/library/pa-atom/ > - sparc64 uses cas in a loop. > > Whilst true spinlocks are not needed, amd64 is the only architecture > FreeBSD supports that does not require some sort of loop to perform > a 64-bit atomic operation. You can use membar instructions on the SPARCv9 to enforce various memory models (RMO, PSO, TSO, if not full sequential consistency). -- -ChuckReceived on Sun Jul 30 2006 - 10:23:48 UTC
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