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4.1.14
System Status Management Function
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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 inter-
vals, round robin scheduling required for the TSS is accomplished (See Figure 4.24)
Move the end of the queue
1
taskA
Priority
2
3
n
taskB
taskC
taskD
taskE
taskF
Figure 4.24 Ready Queue Management by rot_rdq Service Call
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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 ob-
tained instead of the ID number.
•
Lock the CPU (loc_cpu, iloc_cpu)
Places the system into a CPU locked state.
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Unlock the CPU (unl_cpu, iunl_cpu)
Frees the system from a CPU locked state.
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Disable dispatching (dis_dsp)
Places the system into a dispatching disabled state.
•
Enable dispatching (ena_dsp)
Frees the system from a dispatching disabled state.
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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.