Tutorial 2 - csp

= T2A1 =

1. Extended SCCharts are merely syntactic sugar to Core SCCharts. Each Extended SCChart is expressable in Core SCChart syntax.

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1. Compilation of code from a Core SCChart is much simpler than compiling an extended SCChart. Because of the semantically equality, it's much easier to perform a model-to-model transformation than to compile an extended SCChart.

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1. A basic block is a set of instructions, that can be executed as one piece. Instructions with more than one incoming or outgoing sequential control-flow-edges or tick edges trigger a break between basic blocks.

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1. The ordering of a schedule is influenced by data-dependencies such as write-read, abs.write-rel.write and by the sequential control-flow.

= T2A2 =

Created:

Received:

= T2A4 =

=== (% style="font-size:14.0px; line-height:1.4285715" %)Extended features:(%%) ===

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* Count Delay: Wait 5 seconds.

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Transformation: External counter. Reset in entry action. Count in during action. During action in parent state here because of empty complex state "stop".

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The entry action to reset the counter is missing in the automatic transformation. I added the entry action manually and removed the unnecessary initialization of the counter.

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* During: Action during a state is active.

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Transformation: Parallel regions. First increments the counter until the other one finishes.

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* Entry: Action on entering a state.

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Transformation: Additional init-state with immediate transition and the same label the entry action had.

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=== Core SCChart: ===

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[[image:attach:rail.core.png]]

=== Normalize: ===

* Trigger and Effect: Split Trigger and Effects in sequential (immediate) transitions.

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* Surface Depth: States with outgoing non-immediate transitions must only have one outgoing transition.

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[[image:attach:rail.core.normalized.png]]

=== SCG: ===

[[image:attach:rail.scg_dep.conflict.png]]

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Write-write-conflicts may occur while accessing the track-variable. These are between the initialization of the track and lowering the speed or stopping the train when it enters the station again. Thus these conflict can be easily resolved by sequentializing the initialization and the rest of the controller.

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Futhermore there exists a dependency-cycle between the increment and read of the counter-variable and the write and read of the _term-variable. Therefore the SCG is not ASC-schedulable. This can be fixed by sequentialising the counter. We know the counter has to wait 5 seconds. So the counter can be modeled in form of 5 sequential states.

author	version	line-number	content
		1	= T2A1 =
		2
		3	1. Extended SCCharts are merely syntactic sugar to Core SCCharts. Each Extended SCChart is expressable in Core SCChart syntax.
		4	1. Compilation of code from a Core SCChart is much simpler than compiling an extended SCChart. Because of the semantically equality, it's much easier to perform a model-to-model transformation than to compile an extended SCChart.
		5	1. A basic block is a set of instructions, that can be executed as one piece. Instructions with more than one incoming or outgoing sequential control-flow-edges or tick edges trigger a break between basic blocks.
		6	1. The ordering of a schedule is influenced by data-dependencies such as write-read, abs.write-rel.write and by the sequential control-flow.
		7
		8	= T2A2 =
		9
		10	Created:
		11
		12
		13
		14
		15
		16	Received:
		17
		18
		19
		20	= T2A4 =
		21
		22	=== (% style="font-size:14.0px; line-height:1.4285715" %)Extended features:(%%) ===
		23
		24	* Count Delay: Wait 5 seconds.
		25	Transformation: External counter. Reset in entry action. Count in during action. During action in parent state here because of empty complex state "stop".
		26	The entry action to reset the counter is missing in the automatic transformation. I added the entry action manually and removed the unnecessary initialization of the counter.
		27	* During: Action during a state is active.
		28	Transformation: Parallel regions. First increments the counter until the other one finishes.
		29	* Entry: Action on entering a state.
		30	Transformation: Additional init-state with immediate transition and the same label the entry action had.
		31
		32	=== Core SCChart: ===
		33
		34	[[image:attach:rail.core.png]]
		35
		36	=== Normalize: ===
		37
		38	* Trigger and Effect: Split Trigger and Effects in sequential (immediate) transitions.
		39	* Surface Depth: States with outgoing non-immediate transitions must only have one outgoing transition.
		40

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