Outline

Disable dispatching.

C format

 ER      dis_dsp (void);

Parameter(s)

None.

Explanation

This service call transits the system to the dispatching disabled state.

In the dispatching disabled state, the task scheduling is prohibited. Therefore, exclusive processing can be achieved for all tasks.

The operation that transit the system to the dispatching disabled state is as follows.

- dis_dsp

- chg_ims that changes PSW.IPL to other than 0.

The operation that transit the system to the dispatching enabled state is as follows.

- ena_dsp

- ext_tsk

- exd_tsk

- chg_ims that changes PSW.IPL to 0.

Note 1 The dispatching disabled state changed by issuing this service call must be cancelled before the task that issued this service call moves to the DORMANT state.

Note 2 This service call does not perform queuing of disable requests. If the system is in the dispatching disabled state, therefore, no processing is performed but it is not handled as an error.

Note 3 If a service call (such as wai_sem, wai_flg) that may move the status of the invoking task is issued while the dispatching disabled state, that service call returns E_CTX regardless of whether the required condition is immediately satisfied.

Return value

Macro	Value	Description
E_OK	0	Normal completion.
E_CTX	-25	Context error. - This service call was issued from a non-task. - This service call was issued in the CPU locked state. - This service call was issued in the status "PSW.IPL > kernel interrupt mask level".