Optimizing technology mapping for FPGAs using CAMs

This paper describes an inexact string matching scheme devised to improve upon the LURU technique. The scheme uses a set of text strings called common subcircuit expressions (CSEs) to map a high percentage of the subcircuits in a netlist. The inexact matching scheme leverages the don't-care feature of ternary CAMs. Subcircuits are represented as standard-length strings that include wildcards. These strings are called homogeneous LURU strings (HLSs). LURU improves technology mapping by reducing the area requirements of LUT implementations. It also facilitates the profiling of circuits for the discovery of common subcircuits.