We extended the Tcl interface to recognize accesses to this array and link its values to C-variables that are used throughout the SimOS source code. An error is raised if a Tcl parameter is used before it has been written to. Writes to misspelled or non-existent parameters is caught to avoid misspellings.
Parameters are of a static nature and can are set at the start of simulator execution.
To change a parameter from its default value, just set it anywhere after the default.tcl file is sourced. The last parameter value found in the init.simos file will be the one that is used during the simulation. While parameters can be set during the initialization phase of SimOS, they can be read at any time during the course of execution. These checkpoint variables are discussed further in Section 6.2 . Another way that we use Tcl to obtain static information is through the use of the symbol command.