电气自动化 专业 毕业设计英文翻译

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1、无锡科技职业学院中英文翻译Computercontroltechnology1ComputerstructureandfunctionThissectionintroducestheinternalarchitectureofacomputeranddescribeshowinstructionsarestoredandinterpretedandexplainshowtheinstructionexecutioncycleisbrokendownintoitsvariouscomponents.Atthemostbasiclevel,acomputersimplyexecutesbin

2、ary-codedresults.Forageneral-purposeprogrammablecomputer,fournecessaryelementsarethememory,centralprocessingunit(CPU,orsimplyprocessor),anexternalprocessorbus,andaninput/outputsystemasindicatedinFig.3-1A-1.Fig.3-1A-1BasicelementsofacomputerThememorystoresinstructionsanddata.TheCPUreadsandinterpre

3、tstheinstructions,readsthedatarequiredbyeachinstruction,executestheactionrequiredbytheinstruction,andstorestheresultsbackinmemory.OneoftheactionsthatisrequiredoftheCPUistoreaddatafromorwritedatatoanexternaldevice.Thisiscarriedoutusingtheinput/outputsystem.Theexternalprocessorbusisasetofelectricco

4、nductorsthatcarriesdata,addressandcontrolinformationbetweentheothercomputerelements.1-1ThememoryThememoryofacomputerconsistsofasetofsequentiallynumberedlocations.Eachlocationisaregisterinwhichbinaryinformationcanbestored.The“number”ofalocationiscalleditsaddress.Thelowestaddressis0.Themanufacturer

5、definesawordlengthfortheprocessorthatisanintegralnumberoflocationslong.Ineachwordthebitscanrepresenteitherdataorinstructions.FortheIntel8086/87andMotorolaMC6800microprocessors,awordis16bitslong,buteachmemorylocation-27-无锡科技职业学院中英文翻译hasonly8bitsandthustwo8-bitlocationsmustbeaccessedtoobtaineachdat

6、aword.Inordertousethecontentsofmemory,theprocessormustfetchthecontentsoftherightlocation.Tocarryoutafetch,theprocessorplaces(enables)thebinary-codedaddressofthedesiredlocationontotheaddresslinesoftheexternalprocessorbus.Thememorythenallowsthecontentsoftheaddressedmemorylocationtobereadbytheproces

7、sor.Theprocessoffetchingthecontentsofamemorylocationdoesnotalterthecontentsofthatlocation.InstructionsinmemoryInstructionsstoredinmemoryarefetchedbytheCPUandunlessprogrambranchesoccur,theyareexecutedinthesequencetheyap