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<a name="1204693"> </a><font color="#003366" face="Verdana, Arial, Helvetica, sans-serif">5.4 Scheduling</font>
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<a name="1204697"> </a><font size=2 face="Verdana, Arial, Helvetica, sans-serif">An active task may either be running or waiting to run. OS20 ensures the following conditions are met.</font>
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<p> <font size=2 face="Verdana, Arial, Helvetica, sans-serif"><li ><a name="1204698"> </a>The currently executing task is always the one with the highest priority.</font></p>
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<dt> <a name="1204702"> </a><font size=2 face="Verdana, Arial, Helvetica, sans-serif">If a task with a higher priority becomes ready to run, then the OS20 scheduler saves the current task's state and makes the higher priority task the current task. The current task runs to completion unless it is preempted by a higher priority task, and so on. Once a task has completed, the next highest priority task starts executing.</font>
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<p> <font size=2 face="Verdana, Arial, Helvetica, sans-serif"><li ><a name="1204703"> </a>Tasks of equal priority are timesliced, to ensure that they all get the chance to run (when compiling for an ST20C1 a command line option needs to be given; see <a href="task3.htm#1204584"><font color="#0000ff" face="Verdana, Arial, Helvetica, sans-serif"><i>Section⌨️ 快捷键说明
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