Process statements

The process statement is the main construct for a behavioral description. Each process is a sequential program that is typically executed whenever an event occurs on a signal in a specified set of signals. The syntax for the process statement is: The sensitivity list is the set of signals that the process is sensitive to. Any time an event occurs on any signal in the list, the process statement list is executed. This allows a process to behaviorally model a sub-component of a design by re-executing it every time an input to the sub-component changes. However, if the sensitivity list part does not appear, then the process operates differently. In this case, when the last statement in the process is executed, then the process immediately begins executing again from the first statement. The only way to stop this process is with an explicit wait statement that will suspend the process. If the process does not contain a wait statement, then the process would be an infinite loop. A process with a sensitivity list can not contain a wait statement.