Abstract: An improved method is provided for performing register allocation in a compiler. This method determines the allocation of a plurality R of registers of a processor for use during the execution of a software program. The register allocation process is treated as a graph-coloring problem, such that an interference graph is constructed for the software program, the graph is simplified, and an R-coloring the interference graph to the extent possible is attempted. Then, spill code is inserted in the software program each for each uncolored node of the graph, a new interference graph is constructed, and the process is repeated. During the simplification process, nodes with degree greater than or equal to R are removed from the graph in an order dictated by a spill cost metric. During the coloring process, these same nodes are reinserted in the graph in an order dictated by reapplying the spill cost metric.

Abstract: This invention reduces pessimism in cross talk analysis of digital circuits by combining only the peak noises from aggressor nets that can switch simultaneously during the time interval when the downstream receiving latch can sample the errant data. This is done by, first, determining aggressor switching windows and victim sensitivity windows. These windows are then used to determine which combination of noise sources can temporally align so as to cause the greatest noise within the victim sensitivity window.