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附录B翻译原文ElectronicdesignautomationKeywordEDA;IC;VHDLlanguage;FPGAPROCESSDESCRIPTIONThreeobstaclesinparticularbedevilicdesignersinthisdawnofthesystemonachip.Thefirstisactuallyashortfall-thehardwareandsoftwarecomponentsofthedesignlackaunifyinglanguage.Then,asthenumberoflogicgatesperchippassesthemillionmarks,verificationofadesign'scorrectnessisfastbecomingmorearduousthandoingthedesignitself.Andfinally,notonlygatecountsbutchipfrequenciesalsoareclimbing,sothatgettingadesigntomeetitstimingrequirementswithouttoomanydesigniterationsisarecedinggoal.Asisthewontoftheelectronicdesignautomation(EDA)community,theseconcernsarebeingattackedbystart-upcompaniesledbyafewindividualswithbigideasandalittleseedmoney.PARLEZ-VOUSSUPERLOG?Asystemonachipcomprisesbothcircuitryandthesoftwarethatrunsonit.Suchadevicemaycontainanembeddedprocessorcorerunningasoftwaremodem.Mostoften,afterthechip'sfunctionalityisspelledout,usuallyonpaper,thehardwarecom-potentishandedofftothecircuitdesignersandthesoftwareisgiventothepro-grammars,tomeetupagainatsomelaterdate.Thepartofthechipsfunctionalitythatwillendupaslogicgatesandtransistorsiswrit-teninahardwaredesignlanguage-VirologyorVHDL,whilethepartthatwillendupassoftwareismostoftendescribedintheprogramminglanguageCorC++.Theuseofthesedisparatelanguageshamperstheabilitytodescribe,model,anddebugthecircuitryoftheICandthesoftwareinacoherentfashion.Itistime,manyintheindustrybelieve,foranewdesignlanguagethatcancopewithbothhardwareandsoftwarefromtheinitialdesignspecificationrightthroughtofinalverification.JustsuchanewlanguagehasbeendevelopedbyCo-DesignAutomationInc.,SanJose,Calif.Beforelaunchingsuchanambitiousenterprise,cofoundersSimonDavidmann,whoisalsochiefoperatingofficer,andPeterFlakeruledouttheusefulnessofextendinganexistinglanguagetomeetsystem-on-chipneeds.AmongthecandidatesforextensionwereC,C++,Java,andVerilog.Adesignlanguageshouldsatisfythreerequirements,maintainedDavidmann.Itshouldunifythedesignprocess.Itshouldmakedesigningmoreefficient.Anditshouldevolveoutofanexistingmethodology.Noneoftheexistingapproachesfilledthebill.SoDavidmannandFlakesetaboutdevelopingnewco-designlanguagecalledSuperlog.AnaturalstartingpointwasablendofVirologyandCsincefromanalgorithmpointofview,alotofVirologyisbuiltonC,explainedDavidmann.ThentheyspicedtheblendwithbitsandpiecesofVHDLandJava.FromVirologyandVHDL,Superloghasacquiredtheabilitytodescribehardwareaspectsofthedesign,suchassequential,combinatorial,andmultivaluedlogic.FromCandJavaitinheritsdynamicprocessesandothersoftwareconstructs.Evenfunctionslikeinterfaces,protocols,andstatemachines,whichtillnowhaveoftenbeendoneonpaper,canbedescribedinthenewlanguage.Tosupportlegacycodewritteninahardwaredescriptionorprogramminglanguage,SuperlogallowsbothVirologyandCmodulestobeimportedanduseddirectly.Itisimportantforthelanguagetobeinthepublicdomain,accordingtoDavidmann.Thecompanyhasalreadybeguntoworkwithvariousstandardsorganizationstothisend.Nottobeoverlookedistheneedforasuiteofdesigntoolsbasedonthelanguage.RecentlyCo-Designidentifiedanumberofelectronicdesignautomationcompanies,amongthemMagmaDesignAutomation,Sente,andViewlogic,thatwilldeveloptoolsbasedonSuperlog.Co-Designwillalsodevelopproductsforthefrontendofthedesignprocess.ARACETOTHEFINISHNoteveryoneisconvincedthatanewlanguageisneeded.SystemC,amodelingplatformthatextendsthecapabilitiesandadvantagesofC/C++intothehardwaredomainhasbeenproposedasanalternative.SuchlargeandpowerfulcompaniesasSynopsys,Coware,LucentTechnologies,andTexasInstrumentshavebandedtogetherundertheOpenSystemCInitiativetopromotetheirversionofthenext-generationdesignplatform.TogetSystemCofftoarunningstart,thegroupoffersamodelingplatformfordownloadofftheirWebsitefreeofcharge.Theirhopeisalsotomaketheirplatformthedefactostandard.TherationalefordevelopingSystemCwasstraightforward,accordingtoJoachimKunkel,generalmanagerandvicepresidentoftheSystemLevelDesignBusinessUnitatSynopsys.Itwastohaveastandardlanguageinwhichsemiconductorvendors,IPvendors,andsystemhousescouldexchangesystem-levelIPandexecutablespecifications,andtheelectronicdesignautomationindustrycoulddevelopinteroperabletools.SupportersofSystemCbelievethatthewould-bestandardhastobebasedonC++becauseitallowscapabilitiestobeaddedtoitwithoutleavingthelanguagestandard,KunkeltoldJEEESpectrum.MostsoftwaredevelopersuseC++andmanysystemsdevelopersuseC++alreadytodescribetheirsystemsatabehaviorallevel.Buttillnowithasnotbeenpossibletodescribehardwareusingthelanguage.ThedevelopersofSystemChavesolvedthatproblembydefiningnewC++classlibrariesandasimulationkcrne1thatbringtoC++allofthecapabilitiesneededtodescribehardware.Thesenewclassesimplementnewfunctionality,explainedKunkel.Forexample,bitvectors-stringsofzerosandones-andalltheoperationsthatyouwoulddoonthem.TheSystemCdevelopersalsoprovidedaclassofsignedandunsignednumbers,thenotionofasignal,andotherconceptsneededtomodelhardware.Therearestillsomeholes,however.Forexample,itisstillnotpossibletosynthesizeagate-levelnetlistfromaSystcmCdescription.RutsynthesistoolsforSysteniCwouldheanaturalresulto