For WCET analysis, it is important to know the input variables since their values in general must be constrained as much as possible in order to obtain tight program flow constraints from the flow analysis. For an embedded program (or task) written in C or a similar language, the input variables may be
1. values read from the environment using primitives such as ports or memory mapped I/O,
2. parameters to main() or the particular function that invokes the task, and
3. data used for keeping the state of tasks between invocations or used for
task communication, such as external variables, global variables or
In our benchmark program set, we have simply identified if the program has an external variable declaration. We then check if the variable affects the control flow. In this case the program has a potential depenency on inputs, as has not been marked as always single-path. In all other cases, the program has been marked as a always single-path program. These analyses have been performed using SWEET.