Memory architecture provides capabilities for high performance content search using regular expressions and patterns of strings. The architecture creates an innovative memory that can be programmed with content search rules which are used by the memory to evaluate presented content for matching with the programmed rules. When the content being searched matches any of the rules programmed in the Programmable Intelligent Search Memory (PRISM) action(s) associated with the matched rule(s) are taken. Content search rules include of regular expressions which are converted to finite state automata and then programmed in PRISM for evaluating content with the search rules. The PRISM memory provides features for complex regular expression symbols like interval symbol, range detection, complement control, bit masking and the like and enables complex symbols and compact regular expression representation.