Download tasking in esterel, using the multiclock facility of

system. On the completion of the task, a special kind of signal, called a return signal, is sent
back to the synchronous program. The synchronous program then gets results of the task
execution. Possible (synchronous) preemptions make effective implementation of the Esterel
tasking not easy. See reference [2] for detailed explanations and possible implementations
based on so-called "Execution Machines" [3].
Esterel v7 [4] has introduced numerous enhancements: a better structuring of programs
(units), arrays of signals, delayed emissions (next), exact arithmetics, and in the most recent
release, a multiclock support. The simulation and verification environments have also to be
improved with a better handling of data. Unfortunately the former Esterel tasking is no longer
supported. So the following issues were handled in this internship period:
•
Understand the tasking of Esterel v5
•
Get familiar with Esterel v7
•
Analyze the support for tasking using the multiclock concept
•
Perform simulation and performance evaluation of multiclock-based multitask designs.
Tasking is a restricted version of the Esterel V5's tasking. In this study, tasks will be
synchronous programs with their own clock. These tasks will typically perform data
processing, while the main Esterel program will act as a controller/supervisor for the
associated tasks.
1.2 ORGANISATION OF THE REPORT
In this report, we discuss the issues regarding the creation, implementation and to mimic the
behavior of tasks. In the first section, we introduce the necessity of tasks and the semantics of
old conventional task in Esterel v5. Then we discuss the Multiclock facility as it is in Esterel
v7. Later on, we take a comparison of the tasks created using procedures and the Multiclock
facility. Concluding this chapter, we discuss the importance and the need of synchronization.
To better understand the Esterel C++ based simulation model, in the third chapter we explain
the concepts of Execution Machine and how to implement it in software. It includes the
explanation of various types of functions which were to be implemented by the users. We also
take a brief look to the host procedure semantics in Esterel. Here we also explain the main
concept of the tasking mechanism that how it will work and what sorts of signals will be used.
Lastly, we discuss how different clock patterns can be produced under the clock generation
mechanism. Finally, some example problems are considered. We discuss the multiple GCD
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