An emulator and method supporting nvm soft breakpoint debugging

Abstract

The invention introduces an emulator and method supporting NVM soft breakpoint debugging, and relates to the technical field of chip emulation. The emulator includes an emulator debugging module and emulator hardware. The emulator hardware mainly includes modules such as a chip function debugging module, a CPU, a chip MMU, a chip NVM, a chip RAM, and a debugging RAM. The emulator debugging module writes the erasing program and breakpoint data into the erasing program RAM and breakpoint storage RAM of the debugging RAM respectively, and backs up the code of the chip NVM breakpoint address to the breakpoint storage RAM according to the breakpoint data, and controls The CPU executes the erasing program to write the code of the NVM breakpoint address as a breakpoint instruction to realize the breakpoint setting function; change the chip NVM breakpoint instruction back to the breakpoint storage RAM backup code to realize the breakpoint clearing function.

Description

technical field [0001] The invention relates to a chip emulator, in particular to an emulator and method supporting NVM soft breakpoint debugging. Background technique [0002] Breakpoint debugging is the main debugging method of the smart card chip emulator. The emulator usually supports hard breakpoint debugging. Due to the limitation of the number of hard breakpoint registers in the CPU debugging module, the number of hard breakpoints supported by the emulator is small, such as ARM7 core Up to two hard breakpoints are supported. [0003] Soft breakpoints are implemented by setting characteristic values ​​in the code, which are usually called breakpoint instructions. When it is necessary to set a soft breakpoint at a certain address code, the emulator will first backup and protect the code here, and then write the preset breakpoint instruction into this address to overwrite the original code data. When the program runs to the breakpoint instruction, an interrupt will be ...

AI Technical Summary

Problems solved by technology

Since the chip program memory is usually NVM, a few hard breakpoints are difficult to meet the needs of engineers for in-depth debugging. It is hoped that the emulator supports NVM soft breakpoint debugging

In order to solve the problem that NVM cannot set soft breakpoints, some emulators have realized the function of setting soft breakpoints on FLASH. The realization principle is to set soft breakpoints to perform erasing and writing operations on Flash, which requires the emulator to have the Flash programming function, and Ability to write breakpoint instructions in the shortest possible time

Since it takes a certain amount of time to erase and write Flash, you will feel a pause when the Flash breakpoint is executed, and the user experience is not good.

In addition, because the FLASH erasing program and download data are cached in the chip RAM, it is necessary to download the erasing program every time a breakpoint operation is performed to protect the user RAM data, which makes the emulator design complicated.

[0005] In order to solve the problem that the breakpoint debugging speed of the above solution is slow and the chip RAM data needs to be protected, the present invention proposes an emulator that uses hardware circuits to support NVM chip soft breakpoint debugging

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