We disclose a function unit based finite state automata data structure for use in computer program compilers. According to an aspect of an embodiment, the data structure comprises a function unit vector, having no more used bits than there are issue ports for any particular microprocessor, and a plurality of valid template assignments for each function unit vector. In a preferred embodiment, the template assignments are constructed so as to account for dispersal rules associated with the particular microprocessor. Further, the template assignments can be sorted according to priority data.