Technology Adaptation in Logic Synthesis

Systems which synthesize logic implementations from specifications have moved, under the pressure of production requirements, from Boolean minimizers to procedures attempting to satisfy a wider range of criteria. Gate or cell count, taken as a measure of area, continues to be a major factor in design acceptability, but timing constraints, testability, wirability, and efficient use of available primitives are important as well. Additional information, such as "don\´t care" conditions, can be used to improve the design quality. This paper describes how these requirements are specified to and enforced by the Logic Synthesis System (LSS), a tool which has been used in production on gate array chips. Trade-offs between varying requirements, and their effect on the logic produced, are discussed and illustrated with a standard set of examples.