JPS61160162A - Page system of memory - Google Patents

Abstract

PURPOSE:To recognize a using page simply without using a specific hardware by previously writing information indicating each page address in a specific address of each page and reading out the information to recognize the using page. CONSTITUTION:A ROM10 is constituted by dividing its memory space into 2<n> pages and consisting of each page of 2<m> words and a certain page is specified by a page address consisting of n bits which is obtained from a page register 12. A certain word in one page is specified by an address consisting of m bits obtained from an address bus 14 and the data of one word which are specified synchronously with a READ signal are outputted to a data bus 16. In this case, the information indicating each page address is previously written in the leading address of each page of the ROM10. When all m bits of the address applied from the address bus 14 to the ROM10 are turned to '0' and a READ signal is generated, the data of the leading address of 'page 1' are readout and inputted to recognize the using page.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a memory paging system in a computer, and particularly to a technique for recognizing pages in use.

<Conventional technology> For example, in order to prevent a memory area for storing fixed data from occupying much of the limited address space, the following memory paging method is often adopted. ing.

In Figure 2, 10 is a ROM that stores fixed data.
A page is divided into 2n pages, each containing 2m words. An n-bit page address that specifies one page is given from page register 12, and an m-bit address that specifies one word of that page is given from address bus 1.
One word of data read out is output to the data bus 16. The page address is 0PU
K! It is set in the page register 12 by indirect processing or by an external operation.

It is necessary for the CPU etc. to recognize the page in use in ROM10, and for this purpose, the output side of the page register 12 and the data bus 16 are connected via a buffer 18,
The buffer 18 is operated as necessary, and the page address set in the page register 12 is transferred to the data bus 1.
I was trying to load it through 6.

<Problems to be Solved by the Invention> In the conventional page method described above, the buffer 18 and wiring for this are required in order to recognize pages in use, which increases hardware costs. This causes problems in device mounting.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to provide a nine-memory page system that improves the ability to easily recognize pages in use without using special hardware. It is in.

<Means for solving the problem> Therefore, in the present invention, instead of reading the contents of the page register and grating the page, information indicating the page address is written in advance at a specific address of each page. The system reads this information and recognizes the page in use.

<Operation> When the CPU or the like specifies the above specific address and reads data from the memory, the page in use (page address set in the page register) can be determined from the data.

<Embodiment> FIG. 1 shows a page system of a memory according to an embodiment of the present invention. As in the conventional example described above, lROMl0 is 2
It is divided into 2n pages with 1n words as 1 page,
One page is designated by the n-bit page address from page register ν, one word within one page is designated by the m-bit address from address 14, and the designated one is synchronized with the RItAD signal. Word data is output onto data bus 16.

In this embodiment, information indicating the respective page addresses is preliminarily added to the top address of each page in the ROM10, as shown in the figure "Page 1", "Page 2", "Page 3" to [Page 2m J]. It's written down.

Therefore, it is assumed that a page address is set in the page register 12 and "page 1" of the ROM 10 is in use. When it becomes necessary for the OPU etc. to know (read back) the page being used, the RO is sent from the address bus 14.
Set all m-bit addresses given to Ml0 to "0"
to generate the READ signal. Then, the data of the first address of "Page 1", that is, the information indicating that it is "Page 1", is read, and by reading this, it is possible to recognize the page in use.

Note that the page address information may be written to a specified address within each page, and is not limited to the first address.

<Effects of the Invention> As explained in detail above, in the memory page method according to the present invention, pages in use can be recognized by reading data at a specific address of each page, so page There is no need for any hardware to read the contents of registers, which is advantageous in terms of cost and implementation space.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional system. 100・ROM (memory). 120・Page register 14...Address bus 160・Data bus

Claims (1)

[Claims] (1) Specify one of the 2^n pages with the n-bit page address set in the page register, and specify one of the 2^m words within one page with another m-bit address.
In the method of reading data by specifying one page, information indicating each page address is written in advance at a specific address within each page, and this information is read to recognize the page in use. Page method.