GCC's assembly output of an empty program on x86, win32

Question

I write empty programs to annoy the hell out of stackoverflow coders, NOT. I am just exploring the gnu toolchain.

Now the following might be too deep for me, but to cont

Answer 1

I don't have all answers but I can explain what I know.

ebp is used by the function to store the initial state of esp during its flow, a reference to where are the arguments passed to the function and where are its own local variables. The first thing a function does is to save the status of the given ebp doing pushl %ebp, it is vital to the function that make the call, and than replaces it by its own current stack position esp doing movl %esp, %ebp. Zeroing the last 4 bits of ebp at this point is GCC specific, I don't know why this compiler does that. It would work without doing it. Now finally we go into business, call ___main, who is __main? I don't know either... maybe more GCC specific procedures, and finally the only thing your main() does, set return value as 0 with movl $0, %eax and leave which is the same as doing movl %ebp, %esp; popl %ebp to restore ebp state, then ret to finish. ret pops eip and continue thread flow from that point, wherever it is (as its the main(), this ret probably leads to some kernel procedure which handles the end of the program).

Most of it is all about managing the stack. I wrote a detailed tutorial about how stack is used some time ago, it would be useful to explain why all those things are made. But its in portuguese...