DETERMINISTIC SETTING OF REPLACEMENT POLICY IN A CACHE

A cache is configured to receive direct access transactions. Each direct access transaction explicitly specifies a way of the cache. The cache may alter the state of its replacement policy in response to a direct access transaction explicitly specifying a particular way of the cache. The state may be altered such that a succeeding cache miss causes an eviction of the particular way. Thus, a direct access transaction may be used to provide a deterministic setting to the replacement policy, providing predictability to the entry selected to store a subsequent cache miss. In one embodiment, the replacement policy may be a pseudo-random replacement policy. In one embodiment, a direct access transaction also explicitly specifies a cache storage entry to be accessed in response to the transaction. The cache may access the cache storage entry (bypassing the normal tag comparisons and hit determination used for memory transactions) and either read the data from the cache storage entry (for read transactions) or write data from the transaction to the cache storage entry (for write transactions). Other embodiments may set the replacement policy based on other types of transactions.