Editing Control logic (section)

'''Control logic''' is a key part of a software [[computer program|program]] that controls the operations of the program. The control logic responds to commands from the user, and it also acts on its own to perform automated tasks that have been structured into the program.<ref>{{cite web|last=Smith|first=S.E.|title=What Is Control Logic?|url=http://www.wisegeek.com/what-is-control-logic.htm}}</ref>

<!-- Deleted image removed: [[File:Stopwatch chart.png|thumb|250px|right|Model of a simple stopwatch<ref>{{cite journal | url = http://www.csl.sri.com/~rushby/papers/fase04.ps.gz | last1 = Hamon | first1 = G. | last2 = Rushby | first2 = J. | year = 2004 | title = An Operational Semantics for Stateflow | journal = Fundamental Approaches to Software Engineering  | series = Lecture Notes in Computer Science | volume = 2984 | pages = 229–243 | location = Barcelona, Spain | publisher = Springer-Verlag | doi = 10.1007/978-3-540-24721-0_17 | isbn = 978-3-540-21305-5 }}</ref> {{FFDC|Stopwatch chart.png|log=2022 May 11}}]] -->

Control logic can be modeled using a [[state diagram]],<ref>{{cite web | url = http://www.csl.sri.com/users/tiwari/papers/stateflow.pdf | last = Tiwari | first = A. | year = 2002 | title = Formal Semantics and Analysis Methods for Simulink Stateflow Models }}</ref> which is a form of hierarchical [[state machine]].  These state diagrams can also be combined with [[flow charts]] to provide a set of [[computational semantics]] for describing complex control logic.<ref>{{cite conference | last = Hamon | first = G. | year = 2005 | title =  A Denotational Semantics for Stateflow | conference = International Conference on Embedded Software | pages = 164–172 | location = Jersey City, NJ | publisher = ACM | citeseerx = 10.1.1.89.8817 }}</ref> This mix of state diagrams and [[flow charts]] is illustrated in the figure on the right, which shows the control logic for a simple stopwatch.  The control logic takes in commands from the user, as represented by the event named “START”, but also has automatic recurring sample time events, as represented by the event named “TIC”.