Nowadays, for general products, as long as you know the functions you want, they can be realized through MCU+peripheral hardware. There is no need to copy other people's things, which is a waste of time and money!
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Published on 2019-10-16 11:22
Decompiling is like analyzing a pile of shit to understand the digestion (compilation) process of food (source code). If you don’t know the digestion principle, you can’t perfectly reverse it. Similarly, if you don’t know the compilation principle of the compilation tool, you can’t perfectly reverse it.
This post was last edited by wsmysyn on 2018-12-27 10:55 Hex is actually almost the same as the program burned into the flash. In the intel hex-80 format, I remember that it is roughly the address offset, then the length, then the binary program code stored in the sram, and finally a checksum. The data actually written into the sram can be extracted through the tool. . Then the extracted data can be converted from binary code to assembly form using a disassembly tool. (If you have enough experience, you can manually calculate the execution process of the code based on the MCS51 instruction set, the program entry address, and the interrupt vector entry address.) If you have enough experience, you can reverse the code from the assembly code to C language. Disadvantages: 1. As you can see from the above description, it is possible to convert from hex to C language, but if you use hex to convert it into someone's original C file, it is absolutely impossible. 2. Is the disassembly tool intelligent? Because the code generated by compilation and linking is not necessarily stored in continuous space. If the decompilation tool cannot identify it, it is likely to disassemble the discontinuous area as part of the code, which may cause disassembly errors and affect analysis. However, the binary file generated by hex can be manually intervened, the offset address can be calculated manually, and the disassembly can be started at the specified offset address. 3. It is easier to convert more obvious assembly statements into C. For example, 90E6017480F0 can be directly written as a C language sentence: IFCONFIG = 0x80; However, the original C language has a more complex syntax, which is difficult to see from the assembler. There are also some function parameter passing, etc., and you need to read the assembly code carefully to determine what parameters are passed. 4. In summary, the above steps cannot be omitted from hex to C. Can it be converted to C? The answer is possible. How difficult is it? Look at the length of the code, estimate the complexity of the source code, and your own knowledge reserves. However, if you have the time for analysis, you might as well write it yourself. . Advantages: 1. Through analysis, you have mastered the MCS-51 instruction set and can calculate the CPU execution process by hand based on the binary code. 2. By calculating the CPU execution process by hand, you have mastered the firmware working process of 8051 at the binary level 3. You understand how the machine instructions corresponding to the C language statements are implemented. 4. That's it...
If you are not a professional, don't do it. It's better to write it yourself if you have the time. ------------------------------------------------------------------------------------ Direct search: USB to TTL wireless version
Nowadays, for general products, as long as you know the functions you want, they can be realized through MCU+peripheral hardware. There is no need to copy other people's things, which is a waste of time and money!
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