JPH05158784A - Method for acquiring and releasing memory - Google Patents

Abstract

PURPOSE:To reduce an overhead and to improve the processing speed at the time of the acquisition and the release of data necessary at the time of executing a program or a memory area to be used as an operating area. CONSTITUTION:A memory area 1 which stores a memory is equipped with a memory pool part 2 used at the time of operating the acquisition and the release of the memory in the memory area and a memory releasing table part 3 which stores the address and the data of the memory pool released at the time of the release of the memory. Also, a program processing part 4 which processes a program requesting the memory is equipped with a memory acquisition processing means 5 which operates a memory acquisition processing and a memory releasing processing means 6 which operates a memory releasing processing. At the time of the release of the memory, the address of the acquisition and release judgement data (a) of the released memory pool part 2 is set at a release memory and address (c) and the data length (b) of the acquired memory is set at a release data length (d). At the time of the acquisition of the memory, an empty memory is obtained from the memory releasing table part 3 by referring to the address of the released acquisition and release judgement data of the memory pool part 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention acquires data necessary for program execution and a memory area used as a work area.
Regarding the release method. Recently, an IC memory card, an IC chip or the like has been frequently used as an internal memory (RAM) in a small terminal or the like. In order to effectively use these memories, a method is generally adopted in which a memory area is acquired (allocated) when a program needs the memory, and the memory is released (deallocated) when the memory is no longer needed.

As described above, in the case of dynamically acquiring and releasing the memory, the overhead (processing time) of acquiring and releasing the memory is greater than using a fixed memory area.
Will grow. Therefore, in the RAM memory, it is necessary to effectively use the memory area by reducing the overhead for obtaining the memory free area and releasing the used area.

In the dynamic acquisition / release of memory, the largest overhead is the search of free memory. If the memory is repeatedly acquired and released within a limited range of memory, the memory will be mixed with used areas and unused areas as if eaten by a bug. A conceptual diagram of the memory area is shown in FIG. 5A shows an unused state of the memory area, and FIG. 5B shows a mixed state of the used and unused memory areas.

When a free memory is acquired from the memory in the state as shown in FIG. 5B, it is determined which area in the memory is used and which is unused in order from the lower byte of the memory or the upper byte. If there is enough unused area, the area is acquired, and if there is not enough area, the next unused area must be searched.

[0005]

2. Description of the Related Art FIG. 6 shows a conventional operation flowchart for memory acquisition. In the figure, the memory state (whether free or not) used for acquisition / release is checked in order from the upper (or lower) address, and the free memory is searched. The upper (or lower) portion is the program area and precedes the memory area where data can be input. Therefore, the operation flow relates to acquisition of a memory area into which data can be input. (1) 'Set the search range value (memory capacity, that is, the range to be checked). (2) 'Set the search initial address. (3) 'Check if the address setting area is empty memory. If it is not empty memory, add the address. (4) 'If it is a free memory area, check whether the amount of free memory is sufficient. (5) 'If the amount of free memory is sufficient, acquire the memory area. (6) 'If the memory area is acquired, it is determined that there is a free memory, and the address of the free memory is restored to finish. (7) 'If the amount of free memory is not enough, add (increment) the address. (8) 'Check if the area of the added address is larger than the search range value, that is, if there is a remaining amount in the memory area, and if there is a remaining amount, return to the free memory check in (3)'. (9) 'If the address area is smaller than the search range value, that is, if there is no remaining amount in the memory area, the process ends with no free memory.

[0006]

Therefore, the overhead (processing time) for searching a free memory is large,
There has been a problem that the processing time for acquiring the memory is long.

It is an object of the present invention to reduce the overhead at the time of searching for a free memory and improve the processing speed of memory acquisition / release.

[0008]

FIG. 1 is a block diagram showing the principle of the present invention. In the figure, 1 is a memory area for storing a memory, 2 is a memory pool unit used when acquiring / releasing a memory in the memory area, and 3 is an address and data of the memory pool released at the time of releasing the memory. A memory release table unit, 4 is a program processing unit that processes a program that requests memory, 5 is a memory acquisition processing unit that performs a memory acquisition process in the processing unit, and 6 is a memory release processing unit that performs a memory release process.

The memory pool unit 2 is composed of acquisition / release determination data a for determining whether the memory has been acquired or released, and a data length b of the acquired memory. The release determination data a is set to the acquired data, and the acquired memory data length b is set to the memory data length. The memory release table unit 3 includes a release memory address c for storing the address of the memory pool released at the time of releasing the memory and a release data length d for storing the data length of the released memory.

At the time of releasing the memory, the address of the acquisition / release judgment data a of the released memory pool unit 2 is set in the released memory address c, and the data length b of the acquired memory is set.
Is set to the release data length d. When the memory is acquired, the free memory is acquired by referring to the address of the acquired acquisition / release determination data a of the memory pool unit 2 from the memory release table 3.

[0011]

FIG. 2 shows an operation flowchart (No. 1) when the memory is released by the memory release processing means 6 of the present invention, and FIG. 3 is an operation flowchart (No. 2) when the memory is obtained by the memory acquisition processing means 5.

The operation flow chart of the memory release processing means 6 shown in FIG. 2 at the time of memory release is as follows:
Receive an address. (2) It is checked whether the acquisition / release determination data a of the address is acquired data. (3) If the acquired area is not acquired data, the release address is abnormal and the process ends. (4) If the acquired area is acquisition data, release data is set in acquisition / release determination data a. (5) The release memory address c is set in the memory release table 3. (6) Set the release data length d in the memory release table 3. (7) Memory release processing ends.

The operation flow chart for memory acquisition by the memory acquisition processing means 5 of FIG. 3 is as follows: (11) When the memory release table head address is set from the address of the memory release table 3, the acquisition / release determination data ( Release data) a, release memory address c of memory release table 3
To set. (12) Set the required memory length from the program. (13) Memory release table 3 to release memory address c
To win. (14) The acquisition / release determination data a of the address is checked to see if it is a released area (released data), and if it is not released data, it is incremented to the next released memory address position. (15) If it is release data, it is checked whether the requested memory length is shorter than the release data length d. (16) If it is short, the release memory address c in the memory release table 3 is cleared and the release data length d is also set. Clear, (17) Acquire memory area e and end. (18) If the requested memory length is longer than the release data length d, the release memory address c of the memory release table 3 is incremented to the next release memory address position c. (19) It is checked whether the memory release table 3 is finished. If it is not finished, the process returns to (13) and the memory release table 3 is returned.
Repeat the procedure to obtain the free memory address c from. (20) If there is no corresponding released memory, the free memory is searched sequentially from the beginning of the memory pool unit 2 as in the conventional case.

[0014]

FIG. 4 shows an embodiment of a memory area configuration diagram of the present invention. In the figure, 11 is a memory area, 12 is a memory pool section, and 13 is a memory release table section. In the memory area 11, the upper area is preceded by the area of the memory release table section 13, and the lower area thereof is occupied by the area of the memory pool section 12. Memory pool section
Reference numeral 12 includes acquisition / release determination data a, acquisition data length b, and acquired memory area e. The memory release table unit 13 includes release memory address c and release data length d.

In the memory release table 13 of the memory area 11, XXXXXXXX is the address of the acquired memory area, YYYY
YYYY indicates the acquired data length of the memory, in the memory pool section 12 of the memory area 11, AAAAAAAA is the memory acquisition / release determination data, BBBBBBBB is the acquired data length of the memory, and ----
---- indicates a memory area (acquisition / release). Each address and data is composed of 1 byte of 8 bits to 4 bytes of 32 bits. The released data length YYYYYYYY of the memory is the same as the acquired data length BBBBBBBB of the memory.

The memory release processing means checks the acquisition / release determination data AAAAAAAA in the memory pool section 12 based on the received memory address XXXXXXXX to be released, and if the acquired data is stored, obtains it. Data length
Write BBBBBBBB memory area --------. After that, the address of memory released to the memory release table unit 13XXXXX
Set XXXX and data length YYYYYYYY.

First, the processing means at the time of memory acquisition is the release memory address XXXXXXXX in the memory release table 13.
And release data length YYYYYYYY are searched, and whether there is release memory that satisfies the requested memory length is acquired / release determination data AAAA
Check AAAA. If there is the corresponding released memory, acquire the memory area of the acquired data length BBBBBBBB of that memory -------- and clear the released memory address XXXXXXXX and the data length YYYYYYYY in the memory release table 13. .. If there is no corresponding released memory, a free memory is searched sequentially from the beginning of the memory pool unit 12 as in the conventional case.

[0018]

As described above, according to the present invention, the free memory area can be known in advance when the memory is acquired by managing the released area by using the table. The processing time can be shortened.

[Brief description of drawings]

FIG. 1 is a block diagram of the principle of the present invention.

FIG. 2 is an operation flowchart of the present invention (No. 1)

FIG. 3 is an operation flowchart of the present invention (No. 2)

FIG. 4 is an example of a memory area configuration diagram.

FIG. 5 is a conceptual diagram of a memory area

FIG. 6 is an operation flowchart of a conventional example.

[Explanation of symbols]

 1, 11 memory area 2, 12 memory pool section 3, 13 memory release table section 4 program processing section 5 memory acquisition processing means 6 memory release processing means

Claims (1)

[Claims] 1. A memory area (1) for storing a memory,
A memory pool unit (2) used when acquiring / releasing a memory in the memory area, and a memory release table unit (3) storing the address and data of the memory pool released at the time of releasing the memory, The program processing unit (4) for processing the program requesting the memory is provided with a memory acquisition processing unit (5) for performing a memory acquisition process and a memory release processing unit (6) for performing a memory release process. The address of the acquisition / release determination data of the released memory pool section (2) is set to the release memory address of the memory release table (3), and the data length of the acquired memory is set to the release data length of the memory release table (3). When the memory is set and the memory is acquired, the released memory of the memory pool section (2) is acquired from the memory release table (3).
A method for acquiring / releasing memory, characterized by acquiring an empty memory by referring to an address of release judgment data.