x86 equivalent for LWARX and STWCX

Question

I\'m looking for an equivalent of LWARX and STWCX (as found on the PowerPC processors) or a way to implement similar functionality on the x86 platform. Also, where would be

Answer 1

x86 does not directly support "optimistic concurrency" like PPC does -- rather, x86's support for concurrency is based on a "lock prefix", see here. (Some so-called "atomic" instructions such as XCHG actually get their atomicity by intrinsically asserting the LOCK prefix, whether the assembly code programmer has actually coded it or not). It's not exactly "bomb-proof", to put it diplomatically (indeed, it's rather accident-prone, I would say;-).