在armulator中移植uclinux

《在armulator中移植uclinux》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、在ARMulator中移植uClinux在ARMulator中移植uClinux（１）佚名/2008-09-18GettingFamiliarwithuClinux/ARM2.6byHyokS.ChoitheauthorandmaintainerofuClinux/ARM2.6WhyuClinux/ARM2.6?WhywouldyouwanttouseuClinux?TherecouldbemanyreasonstoconsidertheuClinuxforyourembedde

2、dOS.Someofthemcouldbeasfollowing:LightweightYoucanmakeacompletelinux2.6preemptiblekernelimageincludingconsoleandsomebasicdevicedriversandROMFSunder300KB!(zImage)andtheapplicationsinflat-binaryformatareapproximately30~50%lighterthantypicalconventionallinuxELFbinarie

3、s,thankstolighterstandardCandC++libraries.XIPWithmuchsmallerRAM,youcanexecuteyourkernelandeventheapplicationsbyXIP(eXecutionInPlace).Itcouldhelpyoutobootupfaster,althoughtheaccesstimefortheflashorromforbootimageshouldbefastenoughand/orenoughcachesize.(Therecouldbea

4、trade-offbetweenthosevaluesifwewanttofindtheoptimalbalance.)CheaperItisknownthattheMMUcoresizeintypicalARMSoCwaferisabout30%.IntypicalnetworkorembeddedsystemsmorethanahalfofapplicationsdonotneedtheMMU.ManyofRTOSdonotuseMMUindefault,eveniftargetCPUhasone.FullLinuxAP

5、IYoucanusethefullLinuxAPIsonyouruClinuxplatformwithfewexceptions.YoucanusethepThreadinuClibcandthestandardsystemcalls.ThereareplentyofapplicationswhichareportedtouClinuxintheuserlandinuClinuxdistributionpackage.EasiertoadaptOneoftheinterestingnaturesofuClinuxisthep

6、ossibilityofuserapplicationaccessingthewholesystem,includingregistersindevices.Withabitofwrapper,wecanmakethefirmwarecoderunonuClinuxasaplainapplication!Ofcourse,youcanaddsomedevicedriverandcallthelinuxsystemcallsandusemanyopenIpsinmixedwiththeoldfirmwarecode.Ifyou

7、'replanningtomigrateyourfirmwarecodestoLinux,butyou'renotfamiliarwithLinuxsystemprogramming,uClinuxcouldbeagoodstartingpoint.;-)FullLinux2.6kernelfeaturesAlthough,itislighter,itsupportsalmostfullfeaturesofconventionallinux2.6kernel,includingpreemptiblekernelfeature

8、andsomanyfile-systems,devicedrivers.PortingofdevicedriversforconventionalLinuxishandy.Almostallcodesshouldbecompiledwithoutchange,exceptmemorymap