Chapter8MainMemoryLIWensheng,SCST,BUPTTeachinghours:4hStrongpoint:PagingSegmentationChapterObjectives„Toprovidesadetaileddescriptionofvariouswaysoforganizingmemoryhardware„Todiscussvariousmemory-managementtechniques,includingpagingandsegmentation.„ToprovideadetaileddescriptionoftheIntelPentium,whichsupportsbothpuresegmentationandsegmentationwithpaging.WenshengLiBUPLiT2ContentsAboutMemoryManagement？8.1Background8.2Swapping8.3ContiguousMemoryAllocation8.4Paging8.5StructureofthePageTable8.6Segmentation8.7Example:TheIntelpentiumWenshengLiBUPLiT38.1Background„Memoryconsistsofalargearrayofwordsorbytes,eachwithitsownaddress.„Theprogrammustbebroughtintomemoryandplacedwithinaprocessforittoberun.„MainmemoryandregistersareonlystorageCPUcanaccessdirectly„RegisteraccessinoneCPUclock(orless)„MainmemorycantakemanycyclesoftheCPUclock„CachesitsbetweenmainmemoryandCPUregistersWenshen„ProtectionofmemoryrequiredtoensurecorrectgoperationLiBUPLiT4Protection:BaseandLimitRegisters„ApairofbaseandlimitregistersdefinethephysicaladdressspaceWenshengLiBUPLiT5Protection:BaseandLimitRegistersWenshen„ThebaseandlimitregisterscanbeloadedonlybythegLiBUPLioperatingsystem,whichusesaspecialprivilegedinstructions.T6MultistepProcessingofaUserProgramsourceprogramcompilerorassemblerCompiletimeotherobjectmodulesobjectmodulelinkageeditorsystemlibraryloadmoduleloadtimeWenshendynamicallyloadedloaderSystemlibrarygLiBUPLiin-memoryruntimeBinaryMemoryimageT7AddressBindingcomplierloaderNamespece⇒Logicalspace⇒Physicalspace01000………………LoadR1,data100LoadR1,[200]1100LoadR1,[200]………………data：6817200681712006817………………Wenshen2991299gLiBUPLiWhentranslate200to1200？T8BindingofInstructionsandDatatoMemoryAddressbindingofinstructionsanddatatomemoryaddressescanhappenatthreedifferentstages.„Compiletime:Ifmemorylocationknownapriori,absolutecodecanbegenerated;mustrecompilecodeifstartinglocationchanges.