Content Addressable Memory is an expensive component in fixed architecture systems however it may prove to be a valuable tool in online architectures (that is, run-time reconfigurable systems with an online decision algorithm to determine the next reconfiguration). In this paper we define a related problem called an arbitrary mapping function and describe an online architecture. We look at four implementations of an arbitrary mapping function component and compare them in terms of space (number of CLBs used), reconfiguration time, and component latency. All of the implementations offer low latency; which is the primary reason to use a content addressable memory or an arbitrary mapping function. Three of the implementations trade large size for very fast reconfiguration while the last implementation trades is extremely conservative in space but has a large reconfiguration time.