High-level Architectural Simulation of the Torus Routing Chip

* This work was partly supported by the Norwegian Research Council, and was done while the author was at Nordic VLSI, Trondheim. Abstract This paper presents a simulation model of the Torus Routing Chip (TRC) written in Verilog. The model represents the functional behaviour of the routing chip down to the flit (byte) level. The TRCs are self-timed and interconnected in a 4 by 4 torus (mesh with wrap-around) having unidirectional channels along the x and y-dimension. To avoid deadlock situations, the TRC implements two virtual channels on every physical channel. The model is presented in a top down manner with emphasis on the modelling of the packet routing algorithm, asynchronous channels, controlled access to shared resources and the increased complexity caused by virtual channels. The testing of the model as well as experience from using Verilog to develop a high-level architectural simulation is discussed.