JPH096623A - Overlay control method for program - Google Patents

Abstract

PURPOSE: To efficiently use the memory capacity by eliminating the deviation or the variance of the timing in the case of program overlay processing. CONSTITUTION: The whole of a program is divided into a main program 21 for execution timing management and execution control, a subroutine program 22 required all the time, and plural overlay programs 41 and 42 for large clusters of processings whose execution timings don't overlap, and programs 21 and 22 are stored in a resident area 2 of a main storage RAM 1, and programs 41 and 42 are stored in a peripheral storage RAM 4, and the main program selectively copies one of overlay programs 41 and 42 to an overlay area 3 of the main storage RAM 1 in accordance with a preliminarily determined timing and executes it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a program overlay control method, and more particularly, it divides a part of an entire program stored in a main memory area of a program control system and executed into a plurality of overlay programs and stores them in a peripheral memory area. Furthermore, the present invention relates to an overlay control method for selectively storing any of the plurality of overlay programs in the main storage area as needed.

[0002]

2. Description of the Related Art Conventionally, a program overlay control method for executing a large-scale program with this kind of limited main memory capacity is disclosed in, for example, Japanese Patent Laid-Open No. 62-2160.
As disclosed in Japanese Patent Laid-Open No. 57-57, the program is simply divided into a plurality of modules for each function as an overlay program and stored in a peripheral (external) storage area, and the overlay program requested to be executed during the execution of the program is stored in the main storage. Area, but at this time, regarding the overlay program, copy from the peripheral storage area, or
A complicated check is performed to see if it has already been loaded into the main memory area and reloading is unnecessary, or if there is a loadable capacity in the main memory area.

[0003]

In this conventional program overlay control method, whether the overlay program is loaded into the main memory area by the number of functions to be processed, or whether the overlay program is already loaded into the main memory area, Or, since it is confirmed whether it can be loaded, etc., when repeatedly executing the program, the writing time to the main memory area of the overlay program changes depending on the time, and the overall processing time and execution timing of each processing There is the problem of making a difference.

[0004]

According to the present invention, a part of the entire program stored and executed in a main storage area of a program control system is divided into a plurality of overlay programs and stored in a peripheral storage area. In the overlay control method of the program for selectively storing any of the plurality of overlay programs in the main storage area according to, a main memory area is a resident area that is not replaced and an overlay area that is replaced. Split into
A plurality of overlay target processes in which the processing functions each including a combination of a plurality of element processes of the entire program are classified in a time series, and the element processes are grouped as much as possible and execution timings do not overlap with each other, It is divided into a main process for performing execution timing management and execution control of each process and other processes other than the plurality of overlay target processes, and a common element process group from the plurality of overlay target processes is always required as a subroutine process. Separately, the program is divided into a main program, a subroutine program, and a plurality of overlay programs corresponding to the main process, the subroutine process, and the plurality of overlay target processes, respectively, and the main program and the subroutine program are Main storage area A corresponding overlay among the plurality of overlay programs stored in the peripheral storage area based on a result of execution timing determination by the main program stored in a storage area and the plurality of overlay programs stored in the peripheral storage area. There is a step of selecting a program and copying and storing the program in the overlay area of the main storage area.

In the above step, the required storage area capacities of the overlay programs to be stored in the peripheral storage area are calculated and compared with each other. If the storage area capacities are not equal, the program corresponding to the difference is calculated. A part is moved from each overlay program side to the main program side and stored in the main storage area, and the remaining programs whose storage area capacities are substantially equalized are used as the overlay programs in the peripheral storage area. Can be included in the storage.

[0006]

The present invention will be described below with reference to the drawings. FIG. 1 is a hardware configuration diagram of a program control system according to one embodiment of the present invention, and FIG. 2 is a timing chart of the overall processing of a program according to one embodiment of the present invention.

In FIG. 2, the processing of the program of this embodiment includes a main processing A for controlling the whole, a reception processing B for receiving data from the outside, and a transmission processing C for transmitting the data to the outside. , A reception process B and a transmission process C, which are always required in a subroutine process D, and an interrupt process E, which counts the number of timing timing interrupts and manages the timing, which is performed in a constant cycle. It is executed continuously and repeatedly. The interrupt is, for example,
Each timing t1, t2, ..., T obtained by dividing the cycle T into 11 equal parts
The reception process B and the transmission process C are started every 11 times, and the execution is started at timing t2 and timing t7 in each repetition, and the execution is ended before the other process is started. In this way, the processes (reception process B and transmission process C) whose execution timings do not overlap with each other are the targets of the program overlay.

In FIG. 1, the program control system according to the present embodiment has a read-only memory (ROM) 6 for storing and holding various programs, and a processor (CPU) 5 for controlling the entire rising by a startup program in the ROM 6.
And a rewritable memory main memory (RAM) 1 which is a main storage unit for storing a program executed by the CPU 5.
And a rewritable memory (peripheral storage RAM) 4 for storing various programs that cannot be stored in the main memory RAM1 as modules of substantially the same size and transferring them to the main memory RAM1 and storing various data. I have it. The peripheral storage RAM 4 stores an overlay program 41 that performs a reception process B and an overlay program 42 that performs a transmission process C. Main memory RA
M1 is divided into a resident area 2 in which the stored contents are not replaced and an overlay area 3 in which the stored contents are replaced, and the resident area 2 includes a main program 21 for performing the main process A.
, A subroutine program 22 for performing the subroutine processing D, and an interrupt processing program 23 for performing the interrupt processing E are stored. In the overlay area 3, a peripheral storage RAM is stored.
One of the overlay programs 41 and 42 from 4 is overwritten and stored. As a result, the memory size of the overlay area 3 is set to the entire overlay programs 41, 4
Of the two, only the maximum module size is required, and the memory size of the main memory RAM1 can be made smaller than the size of the entire program. Each program in the main memory RAM 1 and the peripheral memory RAM 4 is stored in the ROM 6 in advance for memory protection when the power is cut off.
It is copied from the ROM 6 when the U 5 is started up, and the CPU 5 is operated by the program in the main memory RAM 1.

Next, the operation will be described. First, a processing function consisting of a combination of a plurality of element processes included in the entire program to be executed excluding an interrupt process is chronologically classified and a main process A such as execution timing management and execution control of each process is performed. , A reception process B and a transmission process C, which are overlay target processes whose execution timings do not overlap with each other, and a subroutine process D, which is always required such as commonly used for the reception process B and the transmission process C, and these respective processes A ~
Main program 21 for the entire program corresponding to D
, The overlay program 41 and the overlay program 42, and the subroutine program 22. At this time, the maximum processing time (tbm, tcm) of each of the reception processing B and the transmission processing C to be overlaid is calculated,
Reception processing B is performed based on the difference between the execution start timings (t2, t7).
The inter-process time tbr from the end point of execution of the process to the start point of execution of the transmission process C is calculated. All of the execution programs of the transmission process C are stored in the peripheral storage RAM within this inter-process time tbr.
4 to the overlay area 3, it is determined whether the copyable program portion is the overlay program 42 stored in the peripheral storage RAM 4, and the remaining program portion is moved to the main program 21 side. Similarly, the inter-process time tcr from the end of execution of the transmission process C to the start of execution of the next reception process B is calculated. Within this inter-process time tcr, it is determined whether all the execution programs of the reception process B can be copied from the peripheral storage RAM 4 to the overlay area 3, and the overlay program 41 that stores only the copyable program portion in the peripheral storage RAM 4 is determined.
Then, the remaining program part is moved to the main program 21 side. In addition, these overlay programs 4
The memory sizes required for storing 1, 42 in the overlay area 3 are compared, and a part of the overlay program on the larger side is moved to the main program 21 side so as to be almost equal. After adjusting the division form of the program (processing function) in this way, the main program 21 and the subroutine program 22 are written in the ROM 6, and all the overlay programs 4 modularized to have substantially the same size.
1, 42 are written in the peripheral storage RAM 4. Also, CPU5
Also, the interrupt processing program 23 that performs the interrupt processing E for counting the occurrence of an interrupt for timing timing due to and notifying other processing of the timing is also written in the ROM 6.

When the CPU 5 is started up, the main program 21, the subroutine program 22, and the interrupt processing program 23 are copied from the ROM 6 to the resident area 2 of the main memory RAM 1, and all the overlay programs are copied to the peripheral memory RAM 4. After copying the overlay program 41 to be executed first to the overlay area 3 of the main memory RAM 1, the main program 21 is activated. At the same time, the CPU 5 generates a timing timing interrupt for the program being executed at regular intervals,
The interrupt processing program 23 interrupts the program being executed, counts the number of interrupts, and measures timings t1 to t11 corresponding to the count value. This timing
In the case where the CPU 5 is unique and only needs to match the time T, the count value in the CPU 5 is incremented for each interrupt, and counting from t1 to t11 is performed. In the case of hardware managing the timing, an area for displaying the time T as a certain value is provided. In the interrupt processing program 23, the CPU 5 reads the value and obtains the values t1 to t11 based on the value.

In the main program 21, while referring to and checking the count value of the timing created by the interrupt processing program 23, the execution timing processing is judged and the corresponding program is called and executed. When the programs to be called are the overlay programs 41 and 42, the overlay processing is started at a timing before the execution start time by the time required for copying from the peripheral storage RAM 4 to the overlay area 3 (hereinafter referred to as overlay processing). And call after overlay is complete. (Note that the first overlay program 41 after the start-up has already undergone the overlay processing, so it is not necessary to perform the overlay processing immediately before this start.) Thus, the overlay program corresponding to the reception processing B is performed. 41 and the overlay program 42 corresponding to the transmission processing C are sequentially executed together with the subroutine program 22 while performing overlay processing on the same overlay area 3. As a result, it is possible to execute a program that cannot be stored in the main storage RAM 1 in advance.

The interrupt processing program 23 resets the timing count value to the initial value if it exceeds a predetermined value (equivalent to t11). The main program 21 repeats the above-described processing when the timing count value reaches the initial value.

[0013]

As described above, according to the present invention, the entire program to be stored and executed in the main memory area inside the program control system is always required, together with the main program for execution timing management and execution control. Is divided into a plurality of overlay programs that perform a large group of processing whose execution timings do not overlap with each other, and the main program and the subroutine program are stored in the main storage area, and the plurality of overlay programs stored in the peripheral storage area are stored. The corresponding overlay program is selected from the overlay programs based on the judgment result of the execution timing of the main program and is copied and stored in the overlay area of the main storage area, that is, the overlay is performed in the internal program area at a certain processing timing. Control There are the following effects in Uno. (1) Since the process of copying and storing the overlay program divided by the process for each timing (overlay process) is performed at the process timing defined by the main program, there is no time lag due to the overlay process. Even if the entire program is repeatedly executed, the timing does not vary. (2) The number of overlay processes can be reduced in order to divide the overlay program into as large a range as possible for each timing. (3) Subroutines that are always required in any overlay program are taken out from the overlay program and are stored as a subroutine program in a different area from the overlay area. Therefore, the memory size (capacity) of each overlay program can be reduced. Yes, it can be almost equalized. Further, the equalization can be further promoted by moving a part of the overlay program to the main program side. Therefore, the overlay program can reduce the difference in the required storage area capacity, and although it is large in content, it can be made as small as possible in terms of capacity, eliminating unnecessary areas due to the difference in capacity, and as many programs as possible can be stored internally. Can be set in the main storage area of.

[Brief description of drawings]

FIG. 1 is a hardware configuration diagram of a program control system according to an embodiment of the present invention.

FIG. 2 is a timing chart of overall processing of a program according to an embodiment of the present invention.

[Explanation of symbols]

 1 Main memory RAM 2 Resident area 3 Overlay area 4 Peripheral memory RAM 5 CPU 21 Main program 22 Subroutine program 23 Interrupt processing program 41, 42 Overlay program

Claims (2)

[Claims] 1. A part of the entire program stored and executed in a main storage area of a program control system is divided into a plurality of overlay programs and stored in a peripheral storage area, and the plurality of overlay programs are stored as necessary. In the overlay control method of a program for selectively storing any of the above in the main storage area, the main storage area is divided into a resident area in which the storage content is not replaced and an overlay area in which the storage content is replaced, and the entire program Processing functions consisting of a combination of a plurality of element processings that are included in time series are classified, and a plurality of overlay target processings in which the element processings are grouped as large as possible and execution timings do not overlap with each other, and execution of each processing It performs timing management and execution control, and other processes other than the above-mentioned multiple overlay target processes. And a common element process group is separated from the plurality of overlay target processes as a subroutine process that is always required, and the program corresponds to the main process, the subroutine process, and the plurality of overlay target processes, respectively. Main program, subroutine program,
And divided into a plurality of overlay programs, the main program and the subroutine program are stored in the resident area of the main storage area, the plurality of overlay programs are stored in the peripheral storage area, and executed by the main program. An overlay control method for a program, comprising selecting a corresponding overlay program from the plurality of overlay programs in the peripheral storage area based on a timing determination result and copying and storing the selected overlay program in the overlay area of the main storage area. 2. A required storage area capacity of each overlay program to be stored in the peripheral storage area is calculated and compared with each other. If the storage area capacities are not equal, a part of the program corresponding to the difference is calculated. The program is moved from each overlay program side to the main program side and stored in the main storage area, and the remaining respective programs whose storage area capacities are substantially equalized are stored as the overlay programs in the peripheral storage area. 2. The program overlay control method according to claim 1, further comprising: