Memory access method and device

Abstract

The invention discloses a memory access method, comprising the steps of: judging whether data / instruction to be accessed by a CPU (Central Processing Unit) is in a same page with that which is currently accessed by the CPU, if not, triggering a page swapping mechanism; while swapping the page, storing the number of the page where the data / instruction to be accessed is located, and executing a page swap processing program; updating the data / instruction to be accessed to a program RAM (Random Access Memory) from the external storage; and ending the page swap processing program and resuming after modifying the value of the program counter to be the recorded value of the program counter when the page is determined to be invalid. The embodiment of the invention further provides a memory accessdevice. According to the memory access method and device provided by the invention, the problem that code swapping is required in each page swapping can be avoided, the page swapping code amount is reduced, a uniform interface is provided for each page swapping, so that designers are not needed to regard specific implementation details of the page swapping, and programming difficulty and debugging complexity of the program are obviously reduced.

Description

technical field [0001] The invention relates to computer technology, in particular to a memory access method and device. Background technique [0002] In current computer systems, especially embedded systems, the increasing computing power of hardware enables more and more system functions to be realized, and the scale of software that realizes these functions is also increasing accordingly, so that the executable code of the software The length is getting longer and longer. [0003] For legacy addressing ranges of 2 M The central processing unit (CPU) of the byte, M is a positive integer, and the once addressing range of the CPU in the memory (RAM) space is 2 M bytes, so that the maximum length of the executable code that can be executed each time is also 2 M byte. Obviously, if the length of the executable code exceeds the addressing range, even if all the executable code can be stored in the RAM space, the CPU cannot execute it all at once. At this time, the traditio...

AI Technical Summary

Problems solved by technology

Usually, the size of each page switching code used for page switching is about 32 to 48 bytes, and the number of page switching codes required by a normal-sized software is at least hundreds, which will make the RAM root space The stored page switching code is increased to more than 4KB, and for the RAM in the current integrated circuit, it is obviously unacceptable to use a space of 4KB or more to complete the page switching function, because the amount of RAM space is limited and The cost is high, and this method will cause a lot of RAM space to be occupied and cannot be reused

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