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Chapter 3 Introduction to MR308
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3.5.13 System Status Management Function
• Rotate Task Precedence (rot_rdq, irot_rdq)
This service call establishes the TSS (time-sharing system). That is, if the ready queue is rotated at
regular intervals, round robin scheduling required for the TSS is accomplished (See Figure 3.42)
Move the end of the queue
１
taskA
Priority
２
３
ｎ
taskB taskC
taskD taskE taskF
Figure 3.42 Ready Queue Management by rot_rdq System Call
• Reference task ID in the RUNNING state(get_tid, iget_tid)
References the ID number of the task in the RUNNING state. If issued from the handler,
TSK_NONE(=0=) is obtained instead of the ID number.
• Lock the CPU (loc_cpu, iloc_cpu)
Places the system into a CPU locked state.
• Unlock the CPU (unl_cpu, iunl_cpu)
Frees the system from a CPU locked state.
• Disable dispatching (dis_dsp)
Places the system into a dispatching disabled state.
• Enable dispatching (ena_dsp)
Frees the system from a dispatching disabled state.
• Reference context (sns_ctx)
Gets the context status of the system.
• Reference CPU state (sns_loc)
Gets the CPU lock status of the system.
• Reference dispatching state (sns_dsp)
Gets the dispatching disable status of the system.
• Reference dispatching pending state (sns_dpn)
Gets the dispatching pending status of the system.