RTL synthesis is relatively quick but produces a detailed output which is slow to process for a large chip - hence pre-synthesis energy and delay models are desirable.
Place-and-route will give accurate wiring lengths but is a highly time consuming investment in a given design point.
A simulation of a placed-and-routed design can give very accurate energy and critical path figures, but is likewise useless for 'what if' style design exploration.
A table of possible approaches:
- | - Without Simulation - | - Using Simulation - |
Without Place and Route | Fast - Design exploration.
Area and delay heuristics needed. | Can generate indicative activity ratios to be used instead of simulation in further runs. |
With Place and Route | Static timing analyser will give an accurate clock frequency. | Gold standard: only bettered by
measuring a real chip. |
37: (C) 2012-18, DJ Greaves, University of Cambridge, Computer Laboratory. |