Parallel Logic Simulation of Million-Gate VLSI Circuits Lijuan Zhu, Gilbert Chen, and Boleslaw K. Szymanski Rensselaer Polytechnic Institute, Computer Science Department zhul4,cheng3,
[email protected] Carl Tropper Tong Zhang McGill University, School of Computer Science Rensselaer Polytechnic Institute, ECSE
[email protected] [email protected] Abstract blocks, gate-level logic simulation in which a circuit is modeled as a collection of logic gates, switch-level simu- The complexity of today’s VLSI chip designs makes ver- lation in which circuit elements are modeled as transistors, ification a necessary step before fabrication. As a result, and circuit level simulation in which resistors and wires gate-level logic simulation has became an integral compo- with propagation delays are also represented. nent of the VLSI circuit design process which verifies the Gate-level simulations can be classified into two cate- design and analyzes its behavior. Since the designs con- gories: oblivious and event-driven [13]. In the former, ev- stantly grow in size and complexity, there is a need for ever ery gate is evaluated once at each simulation cycle, while more efficient simulations to keep the gate-level logic veri- in the latter, a gate is evaluated only when any of its in- fication time acceptably small. puts has changed. For large circuits, event-driven simula- The focus of this paper is an efficient simulation of large tion is more efficient because fewer logic gates are evalu- chip designs. We present the design and implementation ated at any instant of the simulated time. Still, very large of a new parallel simulator, called DSIM, and demonstrate and complex systems take substantial amounts of time to DSIM’s efficiency and speed by simulating a million gate simulate, even utilizing event-driven simulators [5].