Assembly Question C++ Source

The transformation from C++ loses information. The mapping from machine code to assembly is quite simple. The mapping from assembly to C++ is very complex, and in general cannot be determined with any kind of accuracy (you could guess, I suppose).

If somebody bothered to write such a program (by using the "guess the mapping" method), it would produce output that would (when compiled) yeild the original input only for the most trivial cases.

Such a program would be completely useless, because the resulting C++ would look nothing like the original C++ that compiled the original .exe, which is why nobody has really bothered to put for the effort.

It is possible to turn the assembly into C++ code, however, it depends if you know the compiler and the compilation rules which built the executable file.

for example, the following line could be compiled in many different ways (two are shown here)

a *= 2;

where a is an unsigned int, could be either

mov eax, a
mul eax, 2
mov a, eax

or

mov eax, a
lea eax, dword ptr [eax * 2]
mov a, eax

This is of course using x86 assembler. So if you know how the compiler has done it you can get it in C++, otherwise learn assembler.

So is thier any roms that have been done this way that you know of and how is C++ mapping to machine code more complex, an example?

Even if it were possible, shall we have a competition to try to list the legal applications? Bet you can't name 10 :)

you could try the open source boomerang decompiler at http://boomerang.sourceforge.net/ but even the people who make it admit that it's not too accurate.

Quote:

Original post by EasilyConfused Even if it were possible, shall we have a competition to try to list the legal applications? Bet you can't name 10 :)

key word being 'legal' huh?

Heh heh.
[cool]