31 lines
499 B
Plaintext
31 lines
499 B
Plaintext
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C R+fencembonceonces
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(*
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* Result: Never
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*
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* This is the fully ordered (via smp_mb()) version of one of the classic
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* counterintuitive litmus tests that illustrates the effects of store
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* propagation delays. Note that weakening either of the barriers would
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* cause the resulting test to be allowed.
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*)
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{}
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P0(int *x, int *y)
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{
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WRITE_ONCE(*x, 1);
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smp_mb();
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WRITE_ONCE(*y, 1);
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}
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P1(int *x, int *y)
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{
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int r0;
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WRITE_ONCE(*y, 2);
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smp_mb();
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r0 = READ_ONCE(*x);
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}
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exists (y=2 /\ 1:r0=0)
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