Decoupling cache capacity management from cache lookup and allocation

A hardware cache including a lookup and address map (LUAM) and a cache memory, the hardware cache being configured to:

• receive a physical memory address;
• compute, by the LUAM, an index into a tag store comprising a plurality of tag entries, the computing being based on the physical memory address;
• compare, by the LUAM, a tag derived from the physical memory address with at least one tag entry in the tag store that is indexed by the index;
• upon identifying a match between the tag and the at least one tag entry, retrieve from the at least one tag entry a cache block address (CBA) of a cache block holding data of the physical memory address in the cache memory, the CBA being independent of the physical memory address;
• and
• perform a lookup into the cache memory using the CBA, the lookup resulting in retrieval of the data of the physical memory address.

A computer system comprising:

• a hardware cache including a lookup and address map (LUAM) and a cache memory, the hardware cache being configured to:
• receive a physical memory address;
• compute, via the LUAM, an index into a tag store comprising a plurality of tag entries, the computing being based on the physical memory address;
• compare, via the LUAM, a tag derived from the physical memory address with at least one tag entry in the tag store that is indexed by the index;
• upon identifying a match between the tag and the at least one tag entry, retrieve from the at least one tag entry a cache block address (CBA) of a cache block holding data of the physical memory address in the cache memory, the CBA being independent of the physical memory address;
• and
• perform a lookup into the cache memory using the CBA, the lookup resulting in retrieval of the data of the physical memory address.