An 8-bit risc-cpu system

A RISC-CPU, n-1 technology, applied in the field of 8-bit RISC-CPU system, can solve the problems of inflexible addressing mode, reduced code efficiency and addressing efficiency, and achieve efficient addressing and improve code efficiency.

Active Publication Date: 2022-05-17
合肥磐芯电子有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Of course, RISC CPU also has disadvantages, such as the addressing mode is not flexible enough, especially when the data memory is large, the code efficiency and addressing efficiency will be reduced

Method used

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  • An 8-bit risc-cpu system
  • An 8-bit risc-cpu system
  • An 8-bit risc-cpu system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047]Embodiment one: this implementation is a data register address mapping method of an 8-bit RISC-CPU system: the method divides the logical address into a single mapping area and a multi-mapping area, and a logical address in a single mapping area corresponds to an actual physical address, and Divided into different banks, one actual physical address in the multi-mapping area has multiple logical addresses, the single-mapping area is all general-purpose registers, and the multi-mapping area has general-purpose registers and special function registers.

[0048] The principle of mapping partitions and sub-banks is as follows:

[0049] Divide the logical address into low 8 bits and high n bits, where n is less than 8, which is determined by the total size of the data memory composed of the RAM connected to the CPU (as a general-purpose register) and special function registers. The size of the data memory is 5k, that is, the maximum code Take the address 0x13FF as an example, ...

Embodiment 2

[0052] Embodiment two: as attached figure 2 Shown, the data memory structure of the present invention, this figure is 0x13FF with the maximum logic address of data memory, and the general-purpose register and the special function register of the multi-mapping area each account for half as an example, first according to "the logic address whose address high n bits are an even number The area is a single-mapping area, and the logical address area with an odd number is multi-mapping area” method to partition the address, the logical address of the single-mapping area (hexadecimal): 0000~00FF (BANK0), 0200~02FF (BANK1), 0400~04FF (BANK2), 0600~06FF(BANK3), 0800~08FF(BANK4), 0A00~0AFF(BANK5), 0C00~0CFF(BANK6), 0E00~0EFF(BANK7), 1000~10FF(BANK8), 1200~12FF( BANK9), this area is generally used as a general-purpose register, and each logical address corresponds to an actual physical address of RAM; the logical address of the multi-mapping area (hexadecimal): 0100~01FF, 0300~03FF, 050...

Embodiment 3

[0053] Embodiment three: as attached image 3 As shown, the address composition modes of the 4 kinds of addressing modes of the data memory of the present invention and the related indirect addressing operation registers, a few specific examples are given below, combined with the attached figure 2 To illustrate the addressing operation of the present invention:

[0054] Direct addressing:

[0055]

[0056]

[0057] The above program realizes 3 operations: lines 2 and 3 pass the value of 0x210 to 0x110; lines 4 and 5 pass the value of 0x211 to 0x180; lines 6 and 7 pass the value of 0x180 to 0x212.

[0058] Among them, 0x210, 0x211, and 0x212 are general-purpose registers in the single-mapping area, 0x110 are general-purpose registers in the multi-mapping area, and 0x180 and 181 are special function registers in the multi-mapping area.

[0059] The above transmission process only needs to use the page cutting instruction BANKBSR0 to write the high address of 0x210 into ...

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Abstract

The invention discloses an 8-bit RISC-CPU system. Including instruction register, instruction decoder, data memory addressing unit, program counter, accumulator, arithmetic logic operation unit, interrupt processing unit and stack processing unit; the instruction register receives the program instruction and transmits it to the instruction decoder and arithmetic logic operation unit; the instruction decoder translates the program instruction and transmits it to the program counter; the data memory addressing unit transmits the data to the accumulator and the arithmetic logic operation unit. The present invention generates a multi-mapping area that does not need to cut pages no matter how big the data memory is, and realizes addressing by one instruction by optimizing the address partition, and puts frequently used special function registers and some general-purpose registers in this area, and only the used single The general-purpose registers in the mapping area are page-cut to achieve efficient addressing and improve code efficiency.

Description

technical field [0001] The invention belongs to the technical field of integrated circuits, in particular to an 8-bit RISC-CPU system. Background technique [0002] With the development of integrated circuits, the application of integrated chips is becoming more and more extensive. CPU is the most common and core component of these integrated circuits. At present, there are mainly two structures of CISC (Complex Instruction Set) and RISC (Reduced Instruction Set) CPU, the CPUs of the two architectures have their own characteristics, and the RISC CPU has the advantages of simplified instruction set, fixed instruction length, small and simple decoding system, and most instructions are completed in one cycle, and its application is expanding day by day. Of course, RISC CPU also has disadvantages, such as the addressing mode is not flexible enough, especially when the data memory is large, the code efficiency and addressing efficiency will be reduced. Contents of the invention...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F9/32G06F9/34
CPCG06F9/321G06F9/34Y02D10/00
Inventor 岳卫杰
Owner 合肥磐芯电子有限公司
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