vxworks嵌入式操作系统

《vxworks嵌入式操作系统》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、嵌入式软件VxWorks编程介绍邹昕光哈尔滨工业大学自动化测控所联系电话：86413531-609E-mail：xgzou@dsp.hit.edu.cnAgendaTaskIntertaskcommunicationISRTaskEachtaskhasitsowncontext,whichistheCPUenvironmentandsystemresourcesthatthetaskseeseachtimeitisscheduledtorunbythekernel.Atask’scontextissa

2、vedinthetaskcontrolblock(TCB).TaskAtask’scontextincludes:-athreadofexecution;thatis,thetask’sprogramcounter-theCPUregistersand(optionally)floating-pointregisters-I/Oassignmentsforstandardinput,output,anderror-adelaytimer-atime-slicetimer-kernelcontrolstr

3、uctures-signalhandlers-debuggingandperformancemonitoringvaluesTaskThedefaulttaskschedulingalgorithminwindispriority-basedpreemptivescheduling.RoundRobinisanoptionalalgorithm.Thewindkernelhas256prioritylevels,numbered0through255.Priority0isthehighestandpr

4、iority255isthelowest.TaskSchedulerControlRoutinesTaskTaskLockWhenataskdisablestheschedulerbycallingtaskLock(),nopriority-basedpreemptioncantakeplacewhilethattaskisrunning.Ifthetaskexplicitlyblocksorsuspends,theschedulerselectsthenexthighest-priorityeligi

5、bletasktoexecute.Whenthepreemption-lockedtaskunblocksandbeginsrunningagain,preemptionisagaindisabled.ThetaskLock()preventtaskcontextswitching,butdonotlockoutinterrupthandling.TaskControlRoutineTasktaskSpawnTaskNameandIDRoutinesTaskInformationRoutinesTask

6、DeletingRoutinesTaskControlRoutinesTaskHookRoutinesTaskSpawnTaskNameandIDRoutinesTaskInformationRoutinesTaskInformationRoutinesTaskDeletingRoutinesTaskDeletingRoutinesTaskControlRoutinesTaskHookRoutinesSharedCodeandReentrancyAsinglecopyofcodeexecutedbymu

7、ltipletasksiscalledsharedcode.Asubroutineisreentrantifasinglecopyoftheroutinecanbecalledfromseveraltaskcontextssimultaneouslywithoutconflict.Modifyglobalorstaticvariables.CodeReentrancySolutionsDynamicStackVariablesGuardedGlobalandStaticVariablesTaskVari

8、ablesDynamicStackVariablesGuardedGlobalandStaticVariablesProvidingamutual-exclusionmechanismtoprohibittasksfromsimultaneouslyexecutingcriticalsectionsofcode.TaskVariablesIntertaskCommunicationSharedDataStructureMutualExclu