JPH02300935A - Data change system for main storage - Google Patents

Abstract

PURPOSE:To economically and efficiently change data in a main storage by virtually dividing respective area in the main storage into plural blocks, changing data by means of setting respective blocks as a unit and setting the blocks including changed information in an idle area. CONSTITUTION:The main storage part is virtually divided at every 1000 addresses, and the change of data is processed in terms of blocks. When a change occurs in data (a) in the main storage part, data of a block 1 comes to be the object of the change, a block 1' including information after the change is stored in 6000th address and succeeding addresses being the idle areas. Then, the address of new data can be obtained by rewriting the head address of the block 1 into the head address of the block 1' and referring an address table. Thus, the change of data is facilitated and the number of packages, which requires exchange, is reduced, whereby economy is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a storage method in a main memory device, and in particular to data storage where modified data is obtained by determining the storage address using a table during metric access. Concerning the change method.

(Prior Art) Conventionally, when the main memory is a ROM, main memory data is changed as shown in FIG. 4 in this type of modification of data on the main memory.

In FIG. 4, in the main memory space, program A is stored in a space between address α and address β. Here, by modifying the program, addresses CI, C2
It is assumed that changes have occurred in two places.

In the conventional method, by converting the ROM package containing the changed part into a package containing the changed information,
Change main memory data. In Figure 4, package R
The ROM represented by 1, R3 is converted into the one in which the changed information is written.

(Problems to be Solved by the Invention) In the conventional main memory data change method described above, when a change occurs in a program, it is necessary to perform package conversion processing for each changed part. That is, the change method by replacing the package has the disadvantage that even if only one location is changed, the storage area for one package is wasted. If too much storage space is wasted in this way, it is uneconomical, and if the number of parts to be changed increases, the amount of work required to change the package increases proportionately.

An object of the present invention is to forbid direct reading based on the storage destination address of the read data given by the central processing unit when reading data in the main memory, always refer to the address table before reading, and to Virtually divides the area into multiple blocks, changes data using these blocks as a unit, sets blocks containing changed information as free space, and reads data from new blocks using the address table. It is an object of the present invention to provide a main memory data changing method configured to eliminate the above-mentioned drawbacks and to change data in the main memory economically and efficiently.

(Means for Solving the Problems) A main memory data modification method according to the present invention is configured to include a first processing means and a second processing means.

The first processing means prohibits direct reading based on the storage destination address of the read data given from the first central processing unit when reading data in the main memory, and performs reading after referring to an address table. It is.

The second processing means virtually divides each area of the main memory into a plurality of blocks, changes data in each block as a unit, and sets the block containing the changed information as a free area;
This is to read data from a new block using the address table.

(Implementation row) Next, the present invention will be explained with reference to the drawings.

FIG. 1 is an explanatory diagram showing an embodiment of a main memory data modification method according to the present invention.

In FIG. 1, the main memory section is virtually divided into 1000 addresses, and data changes are handled in units of blocks. In the address table, the address obtained from the central processing unit is divided by the number of addresses in one block, and the obtained value is used as a key to obtain the starting address of the block containing the data to be read.

For example, if address 1500 is given, the key will be 1 from the following equation (1) because one block is address 1000. That is, 1500 ÷ 10
00 = 1,---remainder 500 (1) If the key part of the address table is 1, the data part is 10
00, it turns out that the starting address of the block where the data to be read is stored is address 1000. Furthermore, since the remainder in equation 111 is 500, it is found that the 500th address from the beginning of the block is the address of the data to be read. That is, 1000 + 500 = 1500 121
The address obtained from equation 12) above is the actual address.

If a change occurs in the data in the main memory, the block
The data will be subject to change. The changed block that includes the changed information and corresponds to the block ■ is the block ■. In process (2), the contents of block (2) are stored from address 6000 onward, which was a free area. In the process @, the start address of the block ■ is rewritten to the start address of the block ■, and the new data address can be obtained by referring to the address table.

FIG. 2 is an explanatory diagram showing data reading processing.

Through the process (3) of obtaining an address from the central processing unit, it is determined that the key is 2. When the process @ that refers to the address table is executed, the start address of the data block is obtained from the data section, and the actual address is obtained by the process θ. In process [phase] K, the information at this address is read from the main memory.

In FIG. 8, the case of FIG. 2 is cited as a processing routine, and a flowchart is shown along with specific obtained values. Here, it is assumed that all data in the main storage section is read using the above method.

(Effects of the Invention) As explained above, the present invention sets the data change block of the main memory as a free area, converts the storage address of the read data given from the central processing unit into an actual address using the address table, Obtaining the changed data facilitates changing the data in the main memory, reduces the number of packages that need to be replaced, and promotes economicalization.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of a main memory data modification method according to the present invention. FIG. 2 is an explanatory diagram showing a processing sequence for reading data from the main memory. FIG. 8 is a flowchart showing the process of FIG. 2. FIG. 4 is an explanatory diagram showing a conventional main memory data changing method using a ROM as the main memory.

Claims (1)

[Claims] a first processing means for prohibiting direct reading based on a storage destination address of the read data given from the central processing unit when reading data in the main memory, and for reading after referring to an address table; Each area of storage is virtually divided into multiple blocks, data is changed using each block as a unit, blocks containing changed information are set as free areas, and data is transferred from the new block using the address table. 1. A method for changing data in a main memory, comprising a second processing means for reading data.