ext_tsk
void ext_tsk (void);
 As a result, the invoking task is unlinked from the ready queue and excluded from the RI600V4 scheduling subject.
 Unlocks the mutexes which are locked by the terminated task. (processing equivalent to unl_mtx will be executed) 
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 If an activation request has been queued to the invoking task (the activation request counter > 0) when this service call is issued, this service call moves the task from the RUNNING state to the DORMANT state, decrements the activation request counter (by subtracting 1 from the activation request counter), and then moves the task from the DORMANT state to the READY state. At this time, processing described in Table 18-2 is done.
 Note 1	 When the return instruction is issued in the task entry function, the same processing as ext_tsk is performed.