An approximate timing analysis method for datapath circuits

We present a novel timing analysis method ACD that computes an approximate value for the delay of datapath circuits. Based on the conditional delay matrix (CDM) formalism we introduced earlier the ACD method exploits the fact that most datapath signals are directed by a small set of control inputs. The signal propagation conditions are restricted to a set of predefined central inputs, which results in significant reductions in the size of the conditions as well as computation time. We have implemented ACD and experimented with reverse-engineered high-level versions of the ISCAS-85 benchmarks. Our results demonstrate up to three orders of magnitude speedup in computation time over exact methods, with little or no loss in accuracy.