| 摘要 |
A method of controlling eviction of cache blocks to override eviction of a value which is reserved for a later operation. When a value is loaded into a cache of the processor and is reserved using a lwarx instruction, it sometimes is evicted from the cache due to the need to store other values in the cache set that the value is mapped to. The present invention provides a method of overriding eviction of reserved values by evicting a selected block of the cache which is a block other than the block containing the reserved value. The reserved value is indicated as being reserved by loading a memory address associated with the value into a reservation unit of the cache, and making a reservation flag in the reservation unit active. In two alternative implementations, the eviction mechanism selects a tentative block for eviction and then determines whether the tentative block is the same as the reserved block (and, if so, chooses a different block for the selected block), or preemptively prohibits the reserved block from being chosen as the selected block. The method of the present invention can be implemented with different types of cache replacement controls, e.g., a random mechanism or a least recently used mechanism.
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