Hermes: A Tutorial and Reference Manual - Researcher - IBM
Hermes: A Tutorial and Reference Manual - Researcher - IBM
Hermes: A Tutorial and Reference Manual - Researcher - IBM
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select(continued) SpecialRules:Allthevariablesidentiedintheeventguardsassociatedwiththeclauseslistedinthestatementqualiermustbeinclass<br />
AppendixB.<strong>Hermes</strong>Operations187 resultvariableidentiedineachbooleanguardassociatedwithaclause inport.Ifthereisanoper<strong>and</strong>,itstypemustbethesameasthatofthe onnormalexitfromtheirassociatedtestclauses.Theentrytypestate foreachbooleanguardclauseisidenticaltotheentrytypestateforthe ment.Allbooleanguardresultvariablesmusthavetheinitattribute theotherwiseclause,isthemeetofthenormalexittypestatefromall thebooleanguardtestclauses(ortheselectstatemententrytypestateiftherearenobooleanguards).Thenormalexittypestatefrom<br />
mustbeoftypepredefined!boolean.Allvariablesassociatedwith selectstatement.Theentrytypestateforeachselectclause,including eventguardsmusthavetheinitattributeonentrytotheselectstate-<br />
listedinthequalier.Otherwise,eachbooleanguardresultvariable<br />
Description:Theinstructionqualiercontainsatableofselectclauses, eachofwhichspeciesoneorbothofaneventguard<strong>and</strong>aboolean astatementclause.Theselectoperationrstexecutesallthestatementsinclausesidentiedbybooleanguards,yieldingvaluesforallthe<br />
guard,aswellasanassociatedstatementclause.Aneventguardis theselectstatementisthemeetofthenormalexittypestatesofall theselectclauses,includingtheotherwiseclause. aninputportvariable,whileabooleanguardidentiesavariable<strong>and</strong><br />
eventguardwhoseassociatedinputportisnonempty,isselected.The booleanguardvariables.Iftheselectoperationhasanoper<strong>and</strong>,itis statementsinthestatementclauseassociatedwiththeselectedclause arethenexecuted.Iftherearenoenabledselectclauses,thenthestatementsinthe\otherwise"clause(identiedintheinstructionqualier)<br />
outport2outport<br />
messagetypeof(outport) Exceptions:Depletion,Disconnected<br />
selectclauseswithtruebooleanguardvaluesareenabled.Inaddition, selectclauseswithoutbooleanguardsareenabled.Ifanyselectclause erationhasnooper<strong>and</strong>s,thebooleanguardvaluesmustbeboolean,<strong>and</strong> isenabled,oneenabledclausewitheithernoeventguard,orwithan clauseforwhichthetestsucceedsbecomes\enabled."Iftheselectop-<br />
testedforequalitywitheachbooleanguardvariable,<strong>and</strong>eachselect<br />
Qualier:select send(outport,message) TypeRules: areexecuted. Seex11.3,p.98
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