A system includes a memory, including a plurality of memory locations having different respective addresses, and a processor. The processor is configured to compute one of the addresses from (i) a first sequence of bits derived from a tag of a data item, and (ii) a second sequence of bits representing a class of the data item. The processor is further configured to write the data item to the memory location having the computed address and/or read the data item from the memory location having the computed address. Other embodiments are also described.