Entries are cached in a function cache by statically assigning a primary key to each cache entry, and first grouping entries having identical primary keys, and dynamically assigning a secondary key to each cache entry, and then second grouping entries in each primary key group into sub-groups according to their secondary keys. The function cache is first accessed with a particular primary key to get the primary key group. Second, the primary key group is accessed with a particular secondary key to get a sub-group, and third, the sub-group is accessed with the same particular secondary key to get a matching cache entry.