Method of increasing storage in processor

Abstract

A method for increasing the memory space of processor which has a CPU and a fixed memory includes providing a extended memory, using an address extender to extend data address and register address in the mode of increasing the number of bits, using a stack pointer to extend stack address in the mode of increasing the number of bits, and storing the increased data to the extended memory.

Description

technical field [0001] The invention relates to a method for increasing the memory in a processor, in particular to a method for increasing the stack memory of the internal data memory in the processor. Background technique [0002] MCS (Micro Computer System) is Intel's general term for microprocessors, and the MCS-31 / 32 and 51 / 52 series processors developed by Intel are widely used in the industry. Generally speaking, a microprocessor only contains a small amount of memory and input and output points. Taking the MCS-51 series single chip as an example, it has a program memory of 4K bytes, a data memory of 128 bytes, and 32 input and output points. The MCS-52 series processors increase the program memory to 8K bytes and the data memory to 256 bytes, while the MCS-31 / 32 and 51 / 52 series processors also use an 8-bit central processing unit unit. The program memory is used to store the program written by the user, which belongs to the read-only memory (ROM), and the data mem...

AI Technical Summary

Problems solved by technology

However, due to the increasingly complex development of the system, the required stack memory and data memory have increased in a large amount. Although the data memory 12 can be expanded by using an external data memory, the size of the stack memory is still limited by the internal memory provided by the processor. data storage

Because the size of the stack memory is limited, in this way, complex programs often have insufficient stack memory, because the program must use the stack to record when calling a subroutine, but limited by the size of the stack memory, in the program It can only call a certain number of subroutines. Moreover, if parameters need to be passed in the subroutine, it is necessary to use a large number of stacks.

However, because the instruction of MCS-51 / 52 is eight bits in length, under the limitation of its instruction set, only one byte (eight bits) is used to represent its internal memory location, so its internal memory size is always limited to 256 words Knot (two to the eighth power)

In the case that the size of the stack memory cannot be expanded, the programmer must pay attention to the number of stacks used when writing the program, which makes the development of the program more difficult

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