1. A method of simulation processing in a data processing system, said method comprising: receiving one or more HDL source files describing a digital design including a plurality of hierarchically arranged design entities, the one or more HDL source files including one or more statements instantiating a plurality of print events within the plurality of hierarchically arranged design entities, each print event having an associated message and at least one associated signal in the digital design; and processing the one or more HDL source files to obtain a simulation executable model, wherein the processing includes building within the simulation executable model a data structure describing the plurality of print events defined for the simulation executable model and associating each of the plurality of print events with its respective associated signal.