Table 1 shows an
ordering table for processor consistency (PC). In
PC, an ordering requirement exists between a load
and all stores that follow it
in program order. That is,
any load X that appears before any store Y in the program order also has to perform before Y. However, no
ordering requirement exists between a store and subsequent loads. Thus, even if store Y appears before load X
in program order, X can still perform before Y.
A truth table is not sufficient to express all conceivable memory consistency models, but a truth table can
be constructed for all commercially implemented consistency models.