JPH0351014B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention has a page table address translation processing method, particularly a segment table and a page table provided for address translation from a virtual address to a real address. The present invention relates to a page table address conversion processing method for quickly determining the virtual address where the page table is located in a data processing device.

[Problems to be solved by conventional technology and invention]

There is a virtual storage method that allocates an independent virtual space (virtual storage area) for each job and executes processing. FIG. 4 shows an example of the configuration of the virtual storage system. 101 in the figure is a given virtual address, 102 is a segment table, 103
is a page table, 104 is a TLB, and 105 is a real page as a result of conversion.

When a virtual address 101 is given, (i) a predetermined entry in the segment table 102 is indexed based on the index s in the address 101, and (ii) a specified page table 103 is indexed based on the contents of the entry. , a predetermined entry is indexed based on the index p in the address 101, and (iii) the content of the entry and the intra-page displacement d in the address 101 are indexed.
A real page 105 is obtained by this. and,
The resulting information on the correspondence between the virtual address and the real address is entered into the TLB 104 and used as a quick lookup table for subsequent conversion.

In this method, so-called segment tables and page tables that describe the address relationship between virtual addresses and real addresses on main memory are used to convert virtual addresses into real addresses on main memory. In such a data processing device, I want to know the real address and virtual address of the page table (B) that manages the virtual page (A) based on the virtual page (A) that I am currently focusing on. There are cases.

In this case, conventionally, the virtual address of the virtual page (A) is given to execute the LRA (Load Real Address) instruction. As a result, the execution of the LRA command shown in Figure 2 (a)
Therefore, when determining the real address of the virtual page (A), the address of the page table is the fourth address.
The actual address of the page table is then determined (FIG. c), as is being determined as explained in connection with the figure. If it is necessary to obtain the virtual address of the page table (Part 2), the page frame table (PFT), which has a correspondence between the real address and virtual address based on the real address, is also used. indexes a table (not shown) called Purge Frame Table Entry (FIG. d), indexes one entry for which said correspondence is provided, namely the page frame table entry (PFTE) (d), and indexes the page frame table entry (PFTE) for which the corresponding purge frame table entry is provided. The stored VBN (Virtual Block)
The virtual address of the page table (Part 2) is calculated using the number (e) in the figure. That is, as will become clearer when corresponding to the above-mentioned FIG. 4, the above-mentioned
When the LRA instruction is executed, for example, at the beginning of the virtual address of the virtual page (A) as shown in Figure 3,
A corresponding segment table entry is obtained from a segment table (not shown) using 12 bits as a segment number. The start address (actual address) of the page table indicated by the segment table entry
and, for example, the page number shown in Figure 3.
In the illustrated page table (PGTE)
Find RBN (Real Block Number). Applicable
The real address of the virtual page (A) is obtained by adding, for example, the displacement within the page shown in FIG. 3 to the RBN. Since such processing is executed by the LRA instruction, the real address of the page table is determined during this process. And after that,
The virtual address of the page table is determined as described above. In this way, the virtual address of the page table is calculated through complex processing, which poses the problem of requiring many processing steps and lengthening the processing time. Ta.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides an address translation table that stores virtual address information where a page table in a system common area is located, and also provides a page specified by the address translation table entry. - Directly points to the virtual address of the table. In other words, each entry in the segment table 102 shown in FIG. 4 stores the real address of the corresponding page table 103, but in the present invention, the segment
As a comparison with the table 102, an address translation table is provided at the same level as the segment table 102, and each entry in the address translation table has a corresponding page number.
A virtual address (instead of a real address) of the table 103 is stored.
Furthermore, at this time, page tables for each space-specific area are provided at the same virtual address, so that a single address translation table is sufficient even if the spaces are different. Therefore, the page table address conversion processing method of the present invention converts the virtual address to a real address in a data processing device having a segment table and a page table that store conversion information for converting a virtual address to a real address. An address translation table is provided to store the virtual address information where the page table for Each corresponding page table is provided at the same virtual address in the space-specific area, and the virtual address at which each of the above page tables is located is calculated from the given virtual address by indexing the address conversion table. Characterized by what I did.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a configuration diagram of one embodiment of the present invention.

In the figure, 1 represents a system common area, 2, 2-0 to 2-n represent a space specific area, 3 represents an address conversion table, and 4, 5-0 to 5-n represent a page table.

In FIG. 1, the virtual storage area is provided with a system common area 1 and a space specific area 2 as shown. And in system common area 1,
A page table 4 is provided to manage addresses of the area. In addition, each spatial specific area 2-
0 to 2-n, page tables 5-0 to 5-n are provided at the same virtual address position, respectively, and the single address translation table 3 provided in the system common area 1 It is structured so that points are given for each.

The address conversion table 3 in the figure is provided in the system common area 1 as described above, and the upper bits in the virtual address, for example 0 to 3 as shown in FIG.
A value generated based on an 11-bit segment number points to an address translation table entry corresponding to, for example, virtual addresses 0 to n shown in FIG. In other words, the address conversion table 3 is
The segment table entry of the conventionally prepared segment table has the same size as the so-called segment table.
As well as pointing to the real address of the table,
Points will be given. Each entry holds a virtual address indicating the location of the page table that manages the segment of the respective virtual storage area.
Specifically, for the entry group corresponding to the system common area 1, for example, the entry group consisting of segment (l+1) to segment n shown in FIG. For the entry group corresponding to the space-specific area 2, for example, the entry group consisting of segments 0 to 1 shown in FIG.
Set virtual addresses for each table group.

In addition, pages and
Each entry in Table 4 and space-specific area 2-
Page table 5- provided in 0 to 2-n
Needless to say, each entry from 0 to 5-n holds information for converting a predetermined virtual address into a real address, as in the prior art.

Next, a procedure for securing the necessary storage area for the page table 4 and the like will be explained.

When the system having the configuration shown in FIG. 1 is initially started, the storage area necessary for the page table 4 that manages the system common area 1 described above is secured in a preferential and fixed manner. Similarly, when creating a space, the storage areas required for the page tables 5-0 to 5-n that manage the space-specific areas 2-0 to 2-n are given priority in all space-specific areas 2. Fixedly secure it so that it has a virtual address. Furthermore, the secured page table 4
And an address translation table 3 for indexing virtual addresses pointing to page tables 5-0 to 5-n is created in the system common area 1. Then, real pages for page table 4 and page tables 5-0 to 5-n are allocated, respectively, when a request is made to reserve the first area for the virtual storage area managed by the page table.

After securing the storage area as described above, when obtaining the virtual address of the page table (B) that manages the virtual page from the virtual address of the virtual page (A), use the virtual address of the virtual page (A) to obtain the virtual address of the page table (B) that manages the virtual page. It is sufficient to obtain the segment number and obtain the address translation table entry corresponding to the segment number. This will give you the virtual address pointing to the page table (B). Furthermore, when it is desired to obtain the real address of the page table (B), the above-mentioned LRA instruction is executed for the obtained virtual address. This results in
You get a real address pointing to a page table.

〔Effect of the invention〕

As explained above, according to the present invention, an address translation table that stores virtual address information in which a page table is located in a system common area is provided, and a page table specified by the address translation table entry is provided. Since the virtual address of the page table can be directly pointed to, the virtual address pointing to the page table can be quickly calculated. Furthermore, since the page tables placed in each space-specific area are provided at the same virtual address, a single address conversion table is sufficient even if the spaces are different.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of one embodiment of the present invention, FIG. 2 is an explanatory diagram illustrating the operation of a conventional page table address conversion processing method, FIG. 3 is an explanatory diagram illustrating address expression, and FIG. 4 shows an example of the configuration of a conventionally known virtual storage system. In the figure, 1 represents a system common area, 2, 2-0 to 2-n represent a space specific area, 3 represents an address conversion table, and 4, 5-0 to 5-n represent a page table.

Claims (1)

[Claims] 1. Segment table and page table storing conversion information for converting virtual addresses to real addresses.
In a data processing device having a table, an address conversion table is provided for storing virtual address information in which a page table for converting the virtual address to a real address is located, and a page table corresponding to a system common area is provided. Page tables are provided in the system common area and corresponding to those in each space-specific area, respectively, at the same virtual address in the space-specific area, and from the virtual address given by indexing the address conversion table. A page table address conversion processing method characterized in that a virtual address at which each of the above page tables is located is calculated.