The top-level module “wraps” all the behavioral modules into a single behavioral unit. It also defines all the global elements, i.e., those elements used by more than one module. It defines two procedures:
● LO_INIT - initialization of all the participating modules.
● LO_MAIN - execution of a single step of all modules.The specification of the top-level module is identified below. It exports the global elements, the initialization and the execution procedures.
Implementation of these procedures is found in the module’s body: