1. Timing analysis of an SDL subset in UPPAAL Anders Hessel Institution of Information Technology Department of Computer Systems Uppsala University M.Sc. Thesis ARTES August 2002 http://www.docs.uu.se/~hessel/sdl2xta/ (ISD Datasystem AB) http://www.isd.se/

2. About the project " Started 1998 at ISD Datasystem AB as a 10 credit point D-level Master thesis (10 weeks) " Continued as a hobby project at spare time. " Extended for “dynamic” SDL processes and the “new” UPPAAL xta format " Became in September 2001 main occupation for 2-3 months supported by Uppsala University. " Report finished in Mars 2002 as a 20 credit point master thesis.

3. UPPAAL " Validation and verification tool built on timed finite-state automata. " Editor, Simulator, and Verifier. " The UPPAAL verifier explores state-space with timing intervals. Model check. " Jointly developed at DoCS/Uppsala and BRICS/Aalborg " http://www.uppaal.com/ http://www.uppaal.com/

4. SDL SDL (Specification and Description Language) is intended for the specification of complex, event driven, real-time, and interactive applications involving many concurrent activities that communicate using discrete signals. ITU-T standard Z.100

5. Contribution Sdl2xta, a tool for converting SDL syntax into UPPAAL's xta format " The run-time system interprets all possible receivers of an implicit output signal. " Dynamic process creation, " Asynchronous communication (queues) " Adding WCET/BCET for timing analysis (model check).

6. Related work (IF project) " IF: Intermediate Format (Bozga, Fernandez Ghirvu, Graf et al at VERIMAG, LSR/IMAG) " SDL2IF, Converting SDL to an Intermediate Format. " Improvement of the toolset ObjectGEODE

7. What we shall create: SDL run-time system " Signals are queued " Queue that delivers input signals which must not be in the state's save-set. " Flattened structure " Signal delivery mechanism explicit and implicit " Timers (per instance) " New instances can be created (in bounds)

8. The building blocks: UPPAAL xta statements = System of process instances = Global variables, (clocks, integers, array of integer, constants) = Channels, ability to synchronize two processes ! And ? = Process instances from process templates = Process templates, can have parameters A Local variables A Locations, initial, committed, urgent, invariant A Transitions 1 Guards 1 Sync 1 Assignment

9. SDL Specification: The syntax to convert from " Stuctural levels: System, Block, Substructure, (Leaf) Block, Process Set, Procedure " Connections: Channel, Signal Route " Types: System, Block, Process, Procedure " Numerous instances of block and processes at a block/process set, initial and maximum

10. Process level specification: " State, Input (parameters), Save " Create, Stop " Nextstate, Join " Decision " Task, “Procedure call” " Output (Explicit, implicit) to, via (gate or channel)

11. Generate from a process set

12. Full run-time system

13. Comparison with SDL2IF " Dynamic process creation not in SDL2IF " Uncertain implicit output, not in SDL2IF " Signal parameters in SDL2IF, only integers in SDL2XTA " Priority inputs not in SDL2XTA " Continuous signals not in SDL2XTA " Enabling conditions not in SDL2XTA " Procedures (inlined in SDL2IF)