JPS63282543A - Virtual address conversion system - Google Patents

Abstract

PURPOSE:To allow users to share a region and to reduce an address conversion table by converting the shared region by a shared region conversion table and then performing address conversion by using a conversion table corresponding to an actual storage. CONSTITUTION:A virtual address 10 is converted into a unified address only for the shared region by using the shared region conversion table 12 corresponding to a virtual storage. Virtual addresses 10 of respective users are converted into the same value as to the same shared region. Here, the value is used to retrieve the conversion table 13 corresponding to the actual storage and then the same actual address 15 is obtained as to the shared region. The conversion table 13 corresponding to the actual storage is retrieved as to an unshared region by virtual addresses 10 by the users, so actual addresses corresponding to the individuals are obtained. Consequently, the user can share the region and even when the virtual storage becomes large, the address conversion table need not be made large.

Description

[Detailed Description of the Invention] [Summary] When converting a virtual address to a real address by referring to a conversion table, it is noted that the area shared among users is smaller than the non-shared area.

Prepare a virtual memory-compatible shared area conversion table that converts addresses to unique addresses only for the shared area, and use the real memory-compatible conversion table after converting the shared area using the shared area conversion table. By performing address conversion, it is possible to share 11 areas among users, and it is also possible to reduce the size of the address conversion table.

[Industrial application field]

The present invention relates to a virtual address conversion method that allows a computer system that employs a multiple virtual memory method to use a conversion table whose size does not depend on the virtual memory size when converting a virtual address to a real address. It is.

[Conventional technology]

FIG. 3 shows an example of the conventional method.

In a computer system that uses multiple virtual memory, the third
(A) As shown in the figure, by dynamically converting the virtual address IO to the real address 15 using the conversion table 30, the virtual space for each user is mapped to the real memory on the main storage device.

The structure of this conversion table 30 can be roughly divided into two types, one shown in FIG. 3(b) and the other shown in FIG. 3(c).

In the method shown in FIG. 3(b), the page number of the real address is entered in the entry of the translation table 30 prepared for virtual memory correspondence for every five users, and the page number of the virtual address is used as an index to convert the translation table 30. With reference to this, the corresponding real page number in the real memory 31 is obtained.

On the other hand, in the method shown in FIG. 3(C), the conversion table 30
Prepare an entry corresponding to real memory in , and find the value of - from the user ID and virtual address.

Position the entry corresponding to real memory using this.

A match between the user ID held there and the virtual address is checked to determine the corresponding real page number. Figure 3 (
The one shown in c) is a so-called associative conversion table 30.
is used.

[Problem that the invention seeks to solve]

FIG. 4 is an explanatory diagram of problems with the conventional method.

The method shown in FIG. 3(b) has a problem in that as the virtual storage expands, a larger conversion table 30 is required. On the other hand, in the method shown in FIG. 3(c), the conversion table 30
The advantage is that the size of is determined by the size of real memory and does not depend on the size of virtual memory. However, this method has a problem in that an area on the same main storage device cannot be shared among different users.

That is, as shown in FIG. 4, the virtual space 40a of user a
and a virtual space 40b of user b.

Consider that by associating the area of virtual address v1 and the area of virtual address (2) in each virtual space with the area of real address R1 of the real memory 31, that area is made a shared area. In the case of the method shown in FIG. 3 (b), the translation table is prepared for virtual memory, so the virtual address Vl
, V2 can be individually associated with the real address R1. However, in the method shown in FIG. 3(C), since the translation table is configured to correspond to real memory, it is not possible to associate multiple virtual addresses with one area, and therefore it is not possible to share the area between users. Can not.

The present invention aims to solve the above problems, and the size of the conversion table does not substantially depend on the virtual memory size.

It also aims to provide a method that allows areas to be shared among users.

Measures to solve problem C] FIG. 1 shows a block diagram of the principle of the present invention.

In FIG. 1, IO is a virtual address indicating the position in the virtual space for each user, 11 is a tag indicating whether it is a shared area or a non-shared area, 12 is a conversion table for shared area, and 13 is a conversion table for real storage.

14 is a conversion table search unit 915 that refers to the conversion table 13 corresponding to real memory and converts a virtual address into a real address.
represents a real address indicating a location in real memory.

The tag 11 of the virtual address 10 indicates whether this virtual address is a shared area or a non-shared area. The shared area conversion table 12 is a table having information for converting a virtual address of a shared area or a part thereof into a virtual address or a part thereof uniquely determined for the shared area in the system.

The conversion table 13 for real storage is a table having information for converting virtual addresses for each user into real addresses for real storage.

The conversion table search unit 14 searches the tag 1 of the virtual address 10.
When 1 indicates a shared area.

Based on the result of address conversion using the shared area conversion table 12, the conversion table 1 corresponding to the real memory is created.
3 to find the real address 15. If tag 11 of virtual address 10 indicates a non-shared area,
Similar to the conventional conversion shown in FIG. 3(c), address conversion is performed using a conversion table corresponding to real storage.

[Effect]

In general, areas shared between users are smaller than non-shared areas. The present invention has been made with attention to this point. That is, only for the shared area, the virtual address 10 is converted using the shared area conversion table 12 that supports virtual memory.
to a unique address. This allows for the same shared area.

Each user's virtual address 10 is translated to the same value. Therefore, if the conversion table search unit 14 searches the conversion table 13 corresponding to real storage using this value, the same real address 15 can be obtained for the shared area.

Regarding the non-shared area, since the conversion table 13 corresponding to real storage is searched using the virtual address 10 for each user, the corresponding real address 15 can be obtained.

〔Example〕

FIG. 2 shows an embodiment of the invention.

In FIG. 2, the same reference numerals as in FIG. 1 correspond to those shown in FIG. 20 is a control register.

21 is a shared ID output circuit, 22 and 23 are selectors, 2
4 represents an arithmetic unit.

In this embodiment, the shared/unshared unit is a segment unit consisting of a plurality of pages. The virtual address 10 consists of a first 1-bit tag 11, a segment ID, a page ID, and an offset within the page.

The common area conversion table 12 is provided for each user,
It is pointed to from a predetermined control register 20. The control register 20 also has a user ID, which is information that identifies a user (space). In the common area conversion table 12,
A true segment ID uniquely determined by the system is set in advance for each segment in the virtual space that is currently a shared area.

When the tag 11 of the virtual address 10 is "0", the virtual address 10 indicates a non-shared area.

The selectors 22 and 23 each lead the segment ID of the virtual address 10 and the user ID of the control register 20 to the arithmetic unit 24 as they are. Conversion to a real address by the arithmetic unit 24 is performed in the same manner as in the conventional art. For example, the computing unit 24
converts the segment ID and user ID into a negative value (for example, j) using a hashing circuit or the like, and uses j as an index to search the conversion table 13 corresponding to the real memory.

The illustrated section A in the conversion table 13 corresponding to real storage stores the corresponding user ID and segment ID.

If a page ID is set and the value matches the input value of the arithmetic unit 24, the page number of the real address stored in that entry is extracted.

Generate real address.

When the tag 11 of the virtual address 10 is '1', the virtual address 10 indicates a shared area. In this case, the segment ID of the virtual address 10 is.

The shared area conversion table 12 converts the segment ID into a true segment ID for the shared area that is uniquely determined by the system. The selectors 22 and 23 respectively guide the true segment ID read from the shared area conversion table 12 and the output of the shared ID output circuit 21, here rOJ, to the arithmetic unit 24. The following operation is the same as for the non-shared area above.

A real address is obtained from the conversion table 13 corresponding to real memory.

〔Effect of the invention〕

As explained above, according to the present invention, it becomes possible to convert a shared area to a real address using a conversion table compatible with real memory, making it possible to share the area among users. With.

Even if the virtual memory becomes larger, there is no need to enlarge the address translation table accordingly.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the principle of the present invention, and Fig. 2U! J shows one embodiment of the wooden invention, FIG. 3 shows an example of a conventional method, and FIG. 4 shows an explanatory diagram of problems with the conventional method. In the figure, 10 is a virtual address, 11 is a tag, 12 is a conversion table for shared area, 13 is a conversion table for real storage,
14 represents a conversion table search unit, and 15 represents a real address.

Claims (1)

[Claims] In a computer system that adopts a multiplexed virtual memory method, there is provided a tag (11) for identifying whether a virtual address is a shared area or a non-shared area, and a tag (11) for each user corresponding to the real memory. Conversion table (1) for real memory that has information for converting virtual addresses to real addresses
3), and a shared area conversion table (corresponding to virtual memory) that has information for converting the virtual address of the shared area or a part thereof into a virtual address or a part thereof uniquely determined for the shared area in the system. 12) and the tag (11) indicates that it is a shared area, address conversion is performed using the shared area conversion table (12), and based on the result, the conversion table (12) for real storage is converted. 13) A virtual address translation method comprising: means (14) for searching.