How to reverse the QNX4.25 with IDA Pro?

Hello all,
I have to reverse a program made by QNX4 to C, then recompiler and biuld it .
Could you give me some ideas?
Thanks for your replay.

You mean take an executable and turn it into C. This is close to impossible. If the executable contains debug symbol it might be worth it. Otherwise you’d end up with a C program with functions and variables names that are totaly meaningless.

There are probably some program out there that can turn assembly code into C.

We can give IDA pro a Plugin ,then IDA Pro can recognize most of the library functions of QNX or watcom. I have completed 10 thousands of lines C. But I don’t know what it is can ber used to do. The head let me did.

Is there a question in your last post?

No yet.
I have compliered the codes got from an executable , and it runs well. So I think it is possible to turn an executable into C.

I didn’t say it was impossible I’m saying that is close to useless because you’d have to be a hacker type of guy to understand what the program is doing. Unless all you want to do is change to some text, change language etc, I guess in those cases it would make sense.

oh, Thanks ~_~

I did this once with “rec”, but the app was about 3 MB as executable.

4/5 could be de(re)compiled to sources, but the Vars were all:


Functions were similar:

fI024521 {


Unreadable, totally unreadable. Since i just tried to find a hardcoded password (strings did not help) for getting unstuck in a small but funny adventure game (do not remember what game it was, but i was surely was pis…d of at not getting the one freaking safe to open), i thought give it a shot. After checking one day source lines i gave up. There is no reasonable structure or workflow with decompiled code. Maybe a Code Visualizer would help here, but at that time there was no such thing … at least non with reasonable output ^^, which is/was obvious the same with rec.

No reasonable output ←

When I was in college a friend of mind, border line genius, downloaded the firmware running in the Commore64 external floppy drive (it has it’s own CPU).

I remember seeing him, laying on the floor with this 15 foot printout of the assembly code. Somehow he manage to understand it all and wrote some code that could take control of the floppy head, which he used to write data between the tracks in some sort of funky pattern. That became a copy protection for games which if my memory is right made it into two games.


I remember a similar thing happening in college with a brilliant guy I met in first year residence at Waterloo. He actually managed to download programs to the CPU in the C64 drive to run programs in parallel with those on the C64 for true multi-tasking. All in hand assembly of course which now seems incredible given the time and effort needed to do it.

I also remember that copy protection becoming very popular on C64 games around 1987-1988 time frame so that you needed special copy programs that wrote those parameterized tracks to the disk. By early 1989 it was obsolete since there were easier ways around it.