JPS63273138A - Overlay system for multi-task - Google Patents

Abstract

PURPOSE:To save the storage area by using a task operating flag updating means and an operating state information updating means to attain overlay control between plural tasks. CONSTITUTION:Segments 1-13 of a load module 10 in a library 1 are loaded to a storage space 5 by an overly segment load means 40 of an overly loader 4. By which task the segments 11-13 constituting a program of the overlay structure are used at present, and how is the operating state are managed by a segment information table 6 revised by an operating state information updating means 42, a control means 43 applies various overlay control between plural tasks to allow one program having the overlay structure to the used in common between plural tasks in one storage space. Thus, the necessity of loading the program duplicatedly into the memory space 5 is eliminated and the capacity of the memory space is saved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information processing system that employs an overlay method, and more particularly to a multitask overlay method that allows a program with an overlay structure to be executed simultaneously among a plurality of tasks.

[Conventional technology]

In conventional information processing systems that employ programs with an overlay structure, one program with an overlay structure can only be executed by one task.

[The shortcomings that the invention attempts to solve]

Therefore, a program that has two segments that are used by multiple tasks and that do not need to be in the storage space at the same time should have an overlay structure so that each task has a copy of the segment in the storage space, or The only options available were to make it possible to use it in multiple tasks by assigning each address to a different memory space, or by making it in a format other than a one-place overlay structure. For this reason, a large area of storage space was required.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a multitask overlay method that can reduce storage space by enabling overlay control between a plurality of tasks.

[Means for solving problems]

To achieve the above object, the present invention provides an information processing system that executes a program with an overlay structure, and includes a task use flag indicating which of a plurality of tasks using the program is used by a segment constituting the program. "In use" when the segment is being used by at least one of the tasks; "End of use" when the segment is no longer in use but still exists in the storage space; If it does not exist, "a segment information table that holds usage state information indicating unused j for each segment constituting the program;" an overlay segment loading means for loading the segment onto the storage space; When a usage request is made, the task usage flag corresponding to the task that issued the usage request is sorted by name, and when the task usage flag is notified that its usage has ended or is overlaid by another segment, the task usage flag is task usage flag updating means for resetting the usage state information; when a certain segment is loaded into the storage space, the usage state information is set to "in use"; and when the segment is finished being used by all tasks or becomes unused; Usage statement B information updating means that sets the usage state information to "end of use" and updates it to "unused" when it is overlaid by another segment and erased from the storage space, Tf''l Overlay segment loading means, task The apparatus includes a control means for controlling one program having an overlay structure to be simultaneously executed by a plurality of tasks in one storage space by using a usage flag updating means and a usage state information updating means.

[Effect]

The segment information updated by the task usage flag update means and usage status information update means shows which task each segment that makes up the overlay structured program is currently being used by, and what its usage status is. For example, when a task is using one of the segments in an overlay relationship and another task requests the use of the other segment, the control means is managed in a table, and for example, when a task uses one of the segments in an overlay relationship, the other task requests the use of the other segment. Various types of overlay control are performed between multiple tasks, such as notification of availability, and one program having an overlay structure is shared among multiple tasks within one storage space.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, in which segment 1
1.12.13 (Each k(1) name is A, B, C)
a library 1 storing a load module 10 (its name is X) having an overlay segment load means 40. Task usage flag updating means 41. An overlay loader 4 including a usage state information updating means 42 and a control means 43, and two tasks 2.3 (each named α and β).
) and a storage space 5 which is a real storage space or a virtual storage space.

The storage space 5 also includes segments 11, 12, or 13 loaded from the library I by the overlay loader 4 and a segment information table 6.

For example, as shown in FIG. 2, the segment information table 6 has a plurality of entries 6 each corresponding to one segment.
a to 6n, and each entry has a segment name 60. Start address 61. Task use flag 62α corresponding to task α, task use flag 62β corresponding to task β, etc. (task use flag 62 provided for each task)
．． Usage state information 63 and other information are stored.

In Figure 1, load module 1 in library 1
Each segment 11 to 13 of 0 is connected to the overlay loader 4.
is loaded into the storage space 5 by the overlay segment loading means 40 of . At this time, the task use flag 62 corresponding to the loaded segment in the segment information table 6 is updated by the task use flag updating means 41.
Among them, the flag corresponding to the task that issued the load request for the segment is set to ON. This ON flag is reset to OFF when the task notifies the end of use of the segment or when the segment is overlaid by another segment. On the other hand, the usage status information 6 of the segment information table 6
3 is updated by the usage state information updating means 42, and when the corresponding segment is loaded into the storage space 5 and is being used by at least one task, it is marked as "in use", and the segment is stored in the storage space 5. When the task use flags of all tasks are OFF, the task is set to the "used" state, and when it is not in the storage space 5, it is reset to the "unused" state.

An example of processing by the task use flag updating means 41 is shown in FIG. As shown in the figure, the task use flag updating means 41
Whether the request to the specified segment is a load request or
or process S1 to determine whether the request is for deletion due to end of use or overlay, and task use flag 62 corresponding to the task that issued the request for the specified segment when it is determined to be a load request by process 31. A process S2 of setting the task use flag to ON, and a process S3 of resetting the task use flag to OFF when it is determined that the request is not a load request are performed.

An example of processing by the usage state information updating means 42 is shown in FIG. As shown in the figure, the usage state information updating means 42 performs a process S11 of determining whether a request for a specified segment is a load request or a deletion request due to termination of use or overlay, and process S11. A process 312 that sets the usage state information 63 corresponding to the specified segment to "in use" when it is determined that the request is a load request by the process SLL, and a corresponding task when it is determined that the request is not a load request by the process SLL. Process 313 for determining whether all use flags 62 are OFF, and Process 3
a process S14 for determining whether the request is for termination of use or a deletion request due to an overlay when it is determined that all are OFF in step S13; A process 315 of setting the information to "end of use" and a process 316 of resetting the usage state information to "unused" when it is determined that the deletion request is made in the process 314, and a process 313 sets the information to "unused". When it is determined that it is being used by a task, it is configured to notify the requestor of the usage status information update means 42 that it is being used, and otherwise to notify that it has ended normally.

Next, the fifth section regarding the processing of the control means 43 at the time of a load request.
This will be explained using figures.

When the overlay loader 4 is notified of the load request from the task, the control means 43 obtains an entry in the segment information table 6 for the specified segment (321).
, executes processing 322 for determining whether the usage status information 63 is "unused". If it is determined in step 322 that the segment is not unused, the task use flag updating means 41 and the use state information updating means 42 are activated with a load request for the specified segment (323, 524). Further, a process S25 is executed to determine whether the upper segment of the overlay tree is in use, and when it is determined in this process 325 that the upper segment is not in use, the segment ID of the upper segment is obtained (S26), and the segment ID of the upper segment is obtained (S26). Processing for upper segment S23. S24.
Repeat S25.

On the other hand, if it is determined in step S22 that the segment is unused, the storage space 5 is freed by loading the specified segment.
Check whether there are any segments to be deleted from (338
), if so, obtain the segment ID (S27), activate the task use flag updating means 41 and the usage statement B information updating means 42 with a deletion request for the overlaid segment (32B, 529), and use When the state information update means 42 notifies that the segment is in use, the control means 43 of the overlay loader 4 informs that the segment specified by the load request is unusable.
is notified to the requesting task.Next, if the usage status information updating means 42 ends normally (if No in S30)
, and if there is an upper segment to be overlaid, the segment of the upper segment to be overlaid) 10
Obtaining (332), processing 328 for that segment
- Repeat steps 331. There are various types of processing that can be performed by a task that receives notification of unavailability, such as waiting until the segment that caused the unavailability is finished being used, or moving to another process. Any method can be used.

Next, when it is determined in process 33B or process S31 that there is no segment to be overlaid, the control means 4
3 causes the overlay segment loading means 40 to load the segment specified in the load request in a known manner (333).

Then, the task use flag updating means 41 and the use state information updating means 42 receive a load request for the loaded segment.
and update the segment information table 6 (3
34. 335). Then, it is determined whether or not the upper segment is in use (536), and if it is determined that it is not in use, the segment I of the upper segment
D 337), the process 333. 334.
Repeat 335.

When all processing is completed successfully, overlay loader 4
The control means 43 notifies the request source that the designated segment is available.

FIG. 6 shows an example of the processing performed by the control means 43 when the overlay [I-der 4] receives a notice of end of use.

When the use of the loaded segment is finished and the task notifies the overlay loader 4 of the end of use, the control means 43 sends a use end request to the task use flag updating means 41 and the usage state information for the specified segment. The updating means 42 is activated (341. 342).

Next, the operation of this embodiment will be explained using a program with a specific overlay structure as an example.

For example, as shown in FIG. 7, the load module IO stored in the library 1 in FIG. 1 is composed of three segments: a root segment 11 and segments 12 and 13 that are in an overlay relationship with each other. For example, segment 1 is placed at address 100 on storage space 5.
1 is loaded and used from task 2.3, and task 2 loads segment 12 at address 300, for example. At this time, the segment information table 6 includes segments 11, 12, .
The task usage flag 62 in the entry 6a for segment 11 is 62α for task 2 and 62 for task 3.
Both β are ON and in use. Also segment 12
In the entry 6b for task 2, only the use flag 62α of task 2 is ON, indicating that it is in use, and since segment 13 is unused, both the corresponding task use flags are OFF. In this situation, task 3
When a request to use the segment 12 is issued, the usage state information 63 of the segment 12 is acquired in process S21 of FIG.
23. The segment information table 6 is updated in step S24, and the overlay loader 4 notifies the task 3 that the upper segment 1 is in use and can be used.

Next, when task 2 notifies that the use of segment 12 has ended, processing 341 in FIG. 342, the segment information table 6 is updated. At this time, the usage state information updating means 42 checks whether the usage flags of all tasks in the entry 6b for segment 12 are OFF in step S13, and in the current state, it is being used by task 3 and its usage flag 62β is ON. Therefore, the usage status information is not updated.

Thereafter, when the task 3 also notifies that the use of the segment 12 has ended, the task use flag updating means 41 activated in step S41 updates the task 3 of the entry 6b.
The usage flag 62β corresponding to . is turned OFF, and at that point, the task usage flags of all tasks related to the segment 12 are turned OFF, so that the usage state information updating means 42 activated in step S42 performs processing S13. 314. In S15, the use status information of the second segment is ended.

Next, when a request for use of segment 13 is notified from task 2, processing 521 in FIG. 522, segment 13 is determined to be unused, and processing S27 determines that segment 2, which is the segment to be overlaid, is [[
D is obtained. Then, all the task usage flags of segment 12 to be overlaid are reset in process 828, and the usage state information of segment 2 is updated to unused in process S29. Since the upper segment is not overlaid, the overlay is performed in process S33. The third segment is loaded into the storage space 5 by the segment loading means 40.
and processed 334. At S35, the usage flag 62α of segment 3 is turned ON, and the usage state information is set to “
"In use" is updated, and Task 2 is notified that it is available for use.

The above description has been made for a program with the simplest overlay structure in which there are two tasks, but the present invention can of course also be used in a case where the number of tasks is two or more in a general overlay program. Furthermore, the present invention can be adopted in systems having or without virtual memory space (effects of the invention). Since the programs can be used at the same time, there is no need to load the program twice into the storage space, which has the effect of reducing the amount of main storage space used, and further reduces the capacity of the auxiliary storage device.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a configuration diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of the segment information table 6, FIG. 3 is a flowchart of an example of processing by the task use flag updating means 41, and FIG. The figure is a flowchart of an example of processing by the usage state information updating means 42, and FIG.
3 is a flowchart of the processing example, and FIG. 6 shows the control means 43 at the end of segment use.
FIG. 1 is an explanatory diagram of an overlay tree. In the figure, 1...Library, 2.3...Task, 4...Overlay loader, 5...Memory empty H16
...Segment emotion table, 10...Load module, 11, 12.13...Segment, 40...
- Overlay segment loading means, 41... Task use flag updating means, 42... Usage state information updating means, 43... Control means, 60... Segment name, 6
1...Start address, 62...Task use flag,
63... Usage status information.

Claims (1)

[Scope of Claim] An information processing system that executes a program with an overlay structure, comprising: a group of task use flags indicating which of a plurality of tasks using the program a segment constituting the program is used; and the segment. is being used by at least one of the tasks, "used" is finished but still exists in the storage space, and is "completed" if it does not exist in the storage space. a segment information table that holds usage state information indicating "unused" for each segment constituting the program; an overlay segment loading means that loads the segment into a storage space; and when a usage request is made for a certain segment. A task usage flag update that sets the task usage flag corresponding to the task that has issued the usage request, and resets the task usage flag when it is notified that its usage has ended or is overlaid by another segment. Means, when a certain segment is loaded into a storage space, the usage state information is set to "in use", and when the segment is finished being used by all tasks or becomes unused, the usage state information is set to "in use". a usage status information update unit that updates the overlay segment load unit, task usage flag update unit, and usage status information update unit to “unused” when the segment is overlaid by another segment and erased from the storage space; 1. A multitasking overlay method, characterized in that it is equipped with a control means for controlling a program having an overlay structure to be executed simultaneously in a plurality of tasks in one storage space.