A transactional memory (TM) receives a lookup command across a bus from a processor. The command includes a memory address, a starting bit position, and a mask size. In response to the command, the TM pulls an input value (IV). The memory address is used to read a word containing multiple result values (RVs) and multiple key values from memory. Each key value indicates a single RV to be output by the TM. A selecting circuit within the TM uses the starting bit position and mask size to select a portion of the IV. The portion of the IV is a key selector value. A key value is selected based upon the key selector value. A RV is selected based upon the key value. The key value is selected by a key selection circuit. The RV is selected by a result value selection circuit.