Emulator and method for supporting NVM soft breakpoint debugging

Abstract

The invention discloses an emulator and method for supporting NVM soft breakpoint debugging and relates to the technical field of chip emulation. The emulator comprises an emulator debugging module and emulator hardware, wherein the emulator hardware mainly comprises a chip function debugging module, a CPU, a chip MMU, a chip NVM, a chip RAM, a debugging RAM and other modules. The emulator debugging module writes an erasing and writing program and breakpoint data into an erasing and writing program RAM and a breakpoint storage RAM of the debugging RAM respectively, backs up codes of breakpoint addresses in the chip NVM into the breakpoint storage RAM according to the breakpoint data, and controls the CPU to carry out the erasing and writing program to write the codes of the breakpoint addresses in the NVM to be a breakpoint instruction, and the breakpoint setting function is achieved; the breakpoint instruction in the chip NVM is changed back to the backup codes of the breakpoint storage RAM, and the breakpoint removing function is achieved.

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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