JPH08190491A - Task switching method - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to reduce the time required to determine a task execution request and a task to be executed in real-time processing in which a plurality of tasks are sequentially executed in a time-division manner. It is also possible to execute tasks at the same level or lower. An execution order table 25 in which a plurality of pieces of task data 21 are created and registered in advance and the execution order of the tasks is registered in advance, and a task to be executed in accordance with the execution order of the tasks registered in the execution order table 25 is executed. When determining, the task data 21 of the task that has come around in order
A task switching method in which the inside task status 20 is inspected and the task is executed if the task status is executable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention divides a program for controlling a machine incorporated into a machine tool into fine tasks,
The present invention relates to a task switching method when a plurality of divided tasks are sequentially executed by a time division method.

[0002]

2. Description of the Related Art A conventional method of switching tasks by time division will be described with an example. The task data 35 shown in FIG. 5 is data indicating task information, and when an execution request for a certain task occurs, an area for storing the task data 35 is secured, and the storage area is released at the end of execution of the task. The task data 35 includes a status flag 31 indicating that the task is being executed, suspended, or waiting, priority data 32 that indicates the task execution priority, and restart data 33 that indicates a register value when starting the task, an address value, or the like. , And the next task data start address 34 indicating the start address of the task data of the task for which the execution request is issued after the task.

FIG. 6 shows a task control block 38 waiting for activation for controlling the task data 35.
It is a figure showing the relation between and task data 35a-35d. The activation waiting task control block 38 is a data buffer for managing each task data 35, and the task data 35 generated by a task execution request is generated.
The first task data address 36 that stores the first address of the task data 35 that occurs earliest in the table, and the first address of the task data 35 that occurs the latest in the task data 35 that is generated by the task execution request are stored. It is composed of the final task data address 37.

When a task is requested to be executed, an area for storing the task data 35 of the task is secured and the task data 35 of the task is initialized. Then, the head address of the secured task data 35 is stored in the final task data address 37, and is also stored in the head address of the next task data of the task data 35 of the task for which the execution request is issued before the task. As a result, the task data 35 of the task for which the execution request has been generated is linked, and the task data 35 for the task for which the execution request has been generated can be managed.

In the case of FIG. 6, task data 35a to 35d are generated in response to the execution request of each task, and the task data which has occurred earliest among the task data 35a to 35d is 35a. The address is stored in the head task data address 36. Similarly, the latest task data that occurred is 35d,
The start address of the task data 35d is stored in the final task data address 37. The task data generated next to the task data 35a is 35b, and the start address of the task data 35b is stored in the next task data start address 34a of the task data 35a. The task data 35c is stored in the next task data start address 34b.
The start address of is stored.

In the state of FIG. 6, when an execution request for a certain task is generated, the relationship between the activation waiting task control block 38 and each task data 35a to 35e is as shown in FIG. In FIG. 7, 35e is task data generated by a new task execution request. In the state of FIG. 6, when a new task execution request is generated, an area for storing the task data 35e is secured and the task data 35e is initialized. Then, the start address of the task data 35e is stored in the final task data address 37. Further, the head address of the task data 35e is stored in the next task data head address 34d of the task data 35d of the task for which the execution request is issued before the task.

In the conventional time-division real-time processing, tasks are switched as follows using each of the above-mentioned data.

FIG. 4 is a flow chart showing an example of a processing procedure at the time of switching the task to be executed. In the task switching processing by a timer interrupt or the like, the task interruption processing 27, the activation task determination processing 29, and the task activation processing 30.
Are performed in order. Further, in the task switching process upon completion of task execution, the task execution end process 28, the activation task determination process 29, and the task activation process 30 are performed in order.

Assuming that the task data 3 is in the state shown in FIG.
When a task switching request is generated by a timer interrupt or the like during execution of the task 5a, the task suspension processing 27 is first performed. In the task suspension processing 27, the register value, the address value, etc. at the time of switching are saved in the restart data 33a, the status flag 31a is set to the suspension, and the activation task determination processing 29 is performed. In the activation task determination processing 29, the priority order data 32a to 32 of each task data 35
e is compared, the task with the highest priority is determined as the task to be activated next, and the task activation processing 30 is performed.

If, as a result of the activation task determination process 29, the task data 35b has the highest priority, the task activation process 30 determines the restart data 33 of the determined task.
b and the like are restored, and the state flag 31b is changed to “during execution” to activate the determined task.

When a task switching request is generated due to the completion of task execution, first, task execution end processing 2
8 is performed. In the task execution end processing 28, the storage area of the task data 35 of the task whose execution has ended is released,
Along with that, the task data 35 is changed, and the activation waiting task control block 38 is changed. If the task data 35b is completed in the state of FIG. 7,
When a task switching request is issued, in the task execution end processing 28, the storage area of the task data 35b is released and the task data 35c is set to the next task data start address 34a.
The top address of the is stored (FIG. 8). Then, similarly to the above, the activation task determination processing 29 and the task activation processing 30 are sequentially performed.

[0012]

As described above, in the conventional real-time processing, the control of the activation waiting task control block 38, the securing and releasing of the area for storing the task data 35, the processing at the time of requesting the execution of the task, and the restart data are performed. The saving / restoring 33 and the activation task determination processing 29 are always performed when switching the task to be executed.

However, the time required for the above processing is a wasteful time from the viewpoint of the entire system. Further, in the task switching method described above, when a task having a high priority and a long processing is executed, a task having a priority equal to or lower than the equivalent level may not be executed for a long time.

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, shorten the time required for registration and determination of an execution request task, and facilitate task control.

[0015]

Unlike a program for starting an application program using a personal computer or the like, a program to be incorporated in a machine tool or the like to control the machine has predetermined tasks to be executed at the time of system creation. Moreover, since the tasks to be executed at the time of creating the system are determined in advance, the basic execution order of the tasks can also be determined in advance. Therefore, by providing the task data of all the tasks in advance, it is possible to omit the control of the activation waiting task control block and the processing of securing and releasing the task data storage area. Furthermore, the contents of the execution order table indicating the basic execution order of tasks are set in advance, and the execution order of the tasks is determined according to the execution order table, so that the priority order is always compared at each task switching, It is possible to reduce the time required for the activation task determination processing and to eliminate the long-time continuous processing of a specific task.

When a task status indicating whether or not there is a task execution request is provided for each task and the task status is set to "execute request", it is determined that the task execution request has occurred, and when the turn comes according to the execution order table. Moreover, by checking the task status and deciding whether or not to activate the task, the time required for the task execution request can be reduced.

Further, the relation between tasks such as exclusion between tasks and execution of two or more tasks at the same time is also determined when the system is created. Therefore, by providing a relationship matrix table indicating the relationship between the tasks and changing the task status of each task based on the relationship matrix table when the task execution request is made, control between the tasks becomes easy.

[0018]

According to this method, it is possible to reduce the time required for requesting execution of a task and determining the task to be executed, and it is possible to execute the tasks having the same priority level or lower.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Real-time processing using the task switching method of the present invention will be described below with reference to the drawings of the embodiments. FIG. 1 is a flow chart showing an embodiment of the processing procedure of the task switching method of the present invention. 2 and 9 and 10 show task data 21, an execution order table 25, and a relationship matrix table 26 used in the task switching method of the present invention.
Indicates.

Task names to be executed are registered in advance in the execution order table 25 of FIG. 9 in correspondence with the counter values 1, 2, 3 ... Cn. The task counter stores any of the counter values 1 to Cn, and the task corresponding to the counter value stored in the task counter becomes the highest priority candidate for the task to be executed next.

FIG. 2 shows task data 21, which is provided in advance for each task. The task data 21 is data indicating task information, and includes a status flag 17 indicating that the task is being executed, suspended, or waiting, restart priority data 18 that indicates the priority when restarting the execution of the task, and the task is activated. It is composed of resuming data 19 indicating register values, address values, etc., and a task status 20 indicating the presence or absence of a task execution request.

In the relationship matrix table 26 of FIG. 10, the processing of the task for controlling is registered in advance for each task in correspondence with the task that issues the execution request. For example, when the execution of task 1 is requested, the processing of S12 to S1n is performed on the task data of task 2 to task n according to the relationship matrix table 26 of FIG. The processing is the task status 20 of the partner task, the restart data 1
9 and the like are changed, and by changing these data, the execution request of the partner task is issued or the execution request is canceled.

First, a method of issuing a task execution request will be described. FIG. 3 is a flowchart showing task execution request processing. When requesting the execution of a task,
The task status 20 of the task is set to “execution requested”, and the task data 21 of other tasks are changed based on the relationship matrix table 26 shown in FIG.

Next, the task switching method will be described with reference to FIG.
This will be described with reference to the flowchart of. When a task switching request is generated by a timer or the like, task interruption processing 1,
Each task is switched in order of the activation task determination processing 3 and the task activation processing 4 to switch the tasks. Further, when a task switching request is generated due to the completion of task execution, the task switching processing is performed by sequentially executing the task execution termination processing 2, the activation task determination processing 3, and the task activation processing 4.

When an execution task switching request is generated by a timer interrupt or the like, task interruption processing 1 is performed. In task suspension processing 1, status flag 1 of the task that was being executed
7 is set during interruption, and the restart data 19 is saved. As a result, when the task is executed again, the saved resume data 19 is restored, so that the task can be continuously executed from the suspended state.

After the task interruption processing 1 is completed, the activation task determination processing 3 is performed. In the activation task determination processing 3, the task counter is updated and the task corresponding to the counter value shown in the execution order table 25 is selected. If the task status 20 of the selected task is the execution request, the task is determined to be the task to be executed next. If there is no execution request for the task, the status flag 17 of each task is checked to search for a task whose execution is suspended. If there is a task whose execution is suspended, the restart priority data 18 is checked, and the task with the highest priority is determined as the task to be executed next. If there is no suspended task, the previously determined auxiliary task is determined as the task to be executed next. The auxiliary task refers to a task that is executed when there is no task that has issued an execution request.

After the activation task determination process 3 is completed, a task activation process 4 is performed. In the task activation process 4, the status flag 17
Is changed during execution, the restart data 19 is restored, and the determined task is executed. When an execution task switching request is generated due to the end of task execution, task execution end processing 2
I do. In the task execution end 2 process, the task data 21 of the task being executed is initialized. After the task execution end process 2 is completed, a start task determination process 3 is performed. In the activation task determination processing 3, the status flag 17 of each task is checked to search for a task whose execution is suspended. Then, of the suspended tasks, the task with the highest priority is determined as the task to be executed next. If there is no suspended task, the previously determined auxiliary task is determined as the task to be executed next. After the activation task determination processing 3 is completed, the task activation processing 4 is performed.

[0027]

According to the present invention, since the order of tasks to be executed is determined in advance, it is possible to reduce the time required for registering the execution request task and determining the task to be executed, and to easily control the tasks. It can be carried out.

[Brief description of drawings]

FIG. 1 is a flowchart showing an embodiment of a task switching method according to the present invention.

FIG. 2 is a data diagram showing an example of task data used in the present invention.

FIG. 3 is a flowchart showing task execution request processing of the present invention.

FIG. 4 is a flowchart showing an example of a processing procedure of the task switching method of the present invention.

FIG. 5 is a data diagram showing an example of task data used in a conventional task switching method.

FIG. 6 is a data diagram showing the relationship between a conventional activation waiting task control block and task data.

FIG. 7 is a data diagram showing a state changed from the state of FIG.

FIG. 8 is a data diagram showing a state changed from the state of FIG.

FIG. 9 is a table showing an execution order table used in the task switching method of the present invention.

FIG. 10 is a table showing a relationship matrix table used in the task switching method of the present invention.

[Explanation of symbols]

1, 27 ... Task interruption processing, 2, 28 ... Task execution end processing, 3, 29 ... Activation task determination processing, 4, 30 ... Task activation processing, 17, 31, 33a to 33e ... Status flag, 18, 32, 33a ... 33e ... Resume priority data, 19, 33, 33a-33e ... Resume data, 20 ...
Task status 21, 35, 35a to 35e ... Task data, 25 ... Execution order table, 26 ... Relationship matrix table, 34, 34a to 34e ... Next task data start address, 36 ... Start task data address, 3
7 ... Final task data address, 38 ... Activation waiting task control block.

Claims (2)

[Claims] 1. In real-time processing for sequentially executing a plurality of tasks in a time-division manner, at least a status flag indicating whether the task is executing, waiting, or suspended, and whether or not the task has an execution request. The task data consisting of the task status that indicates the task status, the restart priority data that indicates the priority order when restarting the execution of each task, the register value when starting each task, the restart data that indicates the address value, and the task execution order are With a pre-registered execution order table, when determining the task to be executed according to the execution order of the tasks registered in the execution order table, inspect the task status of the task that has come in order,
A task switching method characterized by executing the task if it is executable. 2. When a task execution request is made, if the task can be executed, the task status of the task that cannot be executed simultaneously with the task is changed to other task data by changing the task status to no execution request. The task switching method according to claim 1, wherein control between tasks is performed.