Access controller and access control method

An access controller and access control technology, applied in the direction of instruments, memory systems, memory address/allocation/relocation, etc., can solve problems such as slow program execution speed

CN100538666CInactive Publication Date: 2009-09-09KK TOSHIBA
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2009-09-09
Estimated Expiration
Not applicable · inactive patent

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Abstract

An access controller includes an access control cache configured to store access control data associating address range information with access permissions. The access control cache reads access control data by selecting a cache line. A line determination device receives an object code of an assembler instruction to be executed by the CPU, and determines a cache line to be selected for accessing the access control cache from the object code. The cache memory determination device determines a cache hit in a case where a memory address to be accessed by an assembly instruction is included in an address range, and outputs a corresponding access permission.
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Description

technical field

[0001] The present invention relates to an apparatus and method for speeding up access to a control cache. Background technique

[0002] When the information of the access control data of each program instruction is referred to, the execution speed of the program becomes slow. Therefore, some pieces of information of the access control data are allocated on the access control cache including the high speed memory. The access control data is referred to only when the access control information of the memory area to be accessed by the program instruction is not allocated on the access control cache (cache miss).

[0003] A Mondrian memory is described in "Mondrian Memory Protection" by Emmett Witchel, Josh Cates, and Kriste Asanovic at the Tenth International Conference on Architectural Support for Programming Languages ​​and Operating Systems (ASPLOS-X), San Jose, California, October 2002 Protection (MMP) scheme. As many access control cache memory areas as...

Examples

Embodiment Construction

[0014] In order to improve the cache hit rate in an access-controlled cache scheme, it is important to simply extract the information (key) required for predicting the memory area to be accessed by a program instruction, and This information is used for judging the memory area. The use of a register number as a key for storing a memory address to be accessed by a program instruction assumes that there is a correlation between a register number storing a memory address to be accessed by a program instruction and an actual memory area to be accessed.

[0015] In contrast, the access control cache device according to the present embodiment uses information based on an assembly instruction to be executed by a program as a key instead of a general-purpose register number to ensure a high cache hit rate. The reason why it is quite effective to use keywords based on assembly instructions in predicting memory regions to be accessed by program instructions is as follows. That is, asse...