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The test-and-set instruction (cont.)
nMutual
exclusion is preserved: if Pi enter CS, the other Pj are busy waiting
nWhen Pi exit CS, the selection of the Pj who will enter CS
is arbitrary: no bounded waiting. Hence starvation is possible
nProcessors (ex: Pentium) often provide an atomic xchg(a,b)
instruction that swaps the content of a and b.
nBut xchg(a,b) suffers from the same drawbacks as
test-and-set