JPH0334045A - Store-in cache device - Google Patents

Abstract

PURPOSE:To improve the access performance by retrieving a directory control part and storing data into a data storage part at the time in a store request process. CONSTITUTION:An address register 1 is prepared to store the address informa tion on the access requests together with a store data register 8 which stores the data information on the store requests, and a read data register 9 which stores the data read out of a data storage part 7. Then a directory control part 2 is retrieved and at the same time the read/write accesses are given to the part 7 in a store request process. As a result, the store request processing performance is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a store-in cache device in a data processing device, and particularly to an improvement in the processing method for operand store requests.

[Prior Art 1] FIG. 3 is a block diagram showing the configuration of a conventional store-in cache device. In the figure, (■) is an address register that stores address information regarding an access request to the store-in cache device. (2) is a directory control unit that performs a search based on part of the address information. (3) is a directory entry; (4) is a comparison circuit that compares the part of the address information that is not involved in the directory search with the directory information in directory entry (3); 6 (5) is a control circuit that makes the directory entry Inputs the tag information in (3) and the comparison result of the comparison circuit (4), and controls the operation regarding the access request to this store-in cache device. (6) is a control latch that is sent to the control circuit (5). (7) is a data storage unit, and (8) is a store data register 1 that stores information regarding a store request. It is a data register.

FIG. 4 is a diagram showing the structure of directory entry (3). In the figure, (3a) and (3b) are directory information (3a) and tag information (3b) regarding data in the corresponding data storage unit (7>). Note that the directory control unit of the store-in cache device An example of the tag information <3b) in AGM Transactions on Computer Systems (^C
M Transactions Computer Sy
stems), Vol. 4, No. 4, 1'), November 1986, pages 273 to 282. Here, it is assumed that the structure is as follows.

Invalid: Indicates that the corresponding information in the data storage unit is invalid.

Readable; the corresponding information in the data storage is valid;
Indicates that read access to this information is possible.

Writable: The corresponding information in the data storage is valid and
Indicates that both read access and store access regarding this information are possible.

FIG. 5 is an operational flowchart showing store request processing in a conventional storage system.

Next, the operation of the conventional example will be explained. In addition.

Since the purpose of the present invention is to improve the store request processing in the storage device, only the operation in response to the store request will be described below.

When the store request is accepted in step S2 of FIG. 5, address information and data information regarding the store request are stored in the address register (]) and the store data register (8), respectively. Subsequently, in step S2, the directory control unit (2) searches for the address information in the address register (1) to find the directory entry (
3> is read out, and a comparison circuit (4>) compares the directory information 19 (3a) with the address information in the address register (1>).This comparison result and the tag information (3b>
Accordingly, in step S3, the control circuit (5) determines whether or not it is possible to store data in the data storage section (7>), and if possible, turns on the control latch (6).In other words, if the comparison result is a match. , and the control latch (6) is turned on only when the tag information (3b) is writable.If the control latch (6) is determined to be on in step S3, the process advances to step S5 and the data in the store data register (8>) is turned on. The data information is stored in the data storage unit (7), the store request process is processed, and the next access request is accepted in step S6.

On the other hand, if the control latch (6) is determined to be off in step S3, the directory entry (3) is
Directory information (3a) and tag information (3b) within
After the operation for changing the state to a state in which data can be stored is performed, the process advances to step S5, and data is stored in the data storage section <7).

[Problems to be Solved by the Invention] In the conventional store-in cache device as described above, in the case of processing a store request, searching the directory control unit,
It is necessary to process the search results in the order of determination and data storage in the data storage unit, which poses a problem in that access performance deteriorates.

The present invention was made to solve this problem, and is a store-in cache that improves access performance by simultaneously executing a search in a directory control unit and storing data in a data storage unit during store request processing. The purpose is to obtain equipment.

[Means to solve the problem] A store-in cash device according to the present invention.

A store iso cache device having a directory control unit and a data storage unit, an address register storing address information regarding an access request to the store iso cache device, and a store register storing data information regarding the store request; a read data register for storing data read from the data storage unit, and simultaneously performs a search by the directory control unit regarding store address information in the address register and read/write access to the data storage unit in response to the store request. At the same time, the information in the redo data register is re-stored in the storage location related to the store address information in the data storage section according to the search result of the directory control section.

[Effect 1] In this invention, the search in the directory control unit and the read/write access to the data storage unit are performed at the same time, thereby improving the access performance of store request processing, and also improving the access performance of the data storage unit based on the search results. By making re-storage possible, if a state in which data cannot be stored in the data storage section is detected by searching the directory control section, the information in the data storage section can be returned to the state before the execution of the store request.

[Embodiment] FIG. 1 is a block diagram showing a store-in cache device according to an embodiment of the present invention. In the figure, 1 (1) ~
(9) is the same as the conventional one.

(10> is a selection circuit that selectively supplies the output of the store data register (8) or the output of the read data register (9) to the data storage! (7) depending on the state of the control latch (6).

FIG. 2 is a diagram showing an operational flowchart of store request processing according to an embodiment of the present invention.

When a store request is accepted in step 311 of FIG. 2 in the storage device configured as described above, the address information and data information regarding this store request are stored in the address register (1) and the store, respectively. Stored in data register (8). Subsequently, in step 311, a search by the directory control unit (2) regarding the address information in the address register (1) and a read/write access to the data storage unit (7) are performed simultaneously. Then, the directory entry <3) is read out, and it is determined in step S12 whether or not the store request processing is possible. In other words.

A comparison circuit (4) compares the directory information (3a) with the address information in the address register (1), and if the comparison result does not match, or if the tag information (3a)
b) is in an invalid or readable state, the control circuit (5
> turns off the control latch (6) as it is impossible to process the store request. Also, if the comparison result is -, and the tag information (3b
) is in the writable state, the control circuit (5>) determines that the store request can be processed and turns on the control latch (6).

On the other hand, read/write access to the data storage section (7) is performed in the following procedure.

First, a read access to the data storage unit (7) regarding the address information in the address register (1) is performed to read out the data before change, and this data before change is stored in the read data register (9). Next, the store data in the store data register (8) is stored in the data storage unit (7) by write access (step 311
).

With the above operations, the store request processing has been completed, so if it is determined in step 311 that the control latch (6) is in the on state, the next access request can be accepted in step S16 as the processing is completed. Also, step S
If the υ control latch (6) is determined to be off in step 12, the +! In order to return the '1 report to the state before the store request processing, the data before change in the read data register (9) is transferred to the selection circuit (10).
is supplied to the data storage unit (7) and re-stored.

moreover.

After a control operation for changing the directory information (3a> and tag information (3b) in the directory entry <3) to a state in which the store request can be processed is performed in step S14, the process advances to step S15 and the pig storage section (7) is executed. Store data is stored in .

[Effects of the Invention] As explained above, the present invention includes an address register in which address information related to an access request to a store-in-cache device is stored, a store data register in which data information related to a store request is stored, and a data readout from a data storage unit. This has the effect of improving the performance of store request processing, as it is equipped with a read data register for storing the stored data, and the directory control section search and read/write access to the data storage section are performed simultaneously during store request processing. .

[Brief explanation of drawings]

FIG. 1 is a block diagram of the configuration of a store isocash device according to an embodiment of the present invention, FIG. 2 is an operation flowchart of the present invention, FIG. 3 is a block diagram of the configuration of a conventional store-in cache device, and FIG. 4 is a block diagram of the configuration of a conventional store-in cache device. In the configuration block diagram of a directory entry in FIG. 3, reference numeral 5171 is a conventional operation flowchart. In the figure, (1)...address register, (2)...
Directory control unit, (3)...Directory entry, (4)...Comparison circuit, (5>...Control circuit, (
6)...Control latch, (7)...Data 3 self-storage section,
(8)...store data register, (9) read data register, (10)...selection circuit. Note that the same reference numerals in each figure indicate the same or equivalent parts.

Claims (1)

[Claims] A store-in cache device having a directory control unit and a data storage unit, the address register storing address information regarding an access request to the store-in cache device, and the store register storing data information regarding the store request. and a read data register for storing data read from the data storage unit, and in response to the store request, the directory control unit searches for store address information in the address register and read/write access to the data storage unit. The store-in method is characterized in that the information in the read data register is re-stored in the storage location related to the store address information in the data storage unit according to the search result of the directory control unit. cache device.