Direct assignment of code to function pointer: not working in gcc 4.x

[Anibal Caceres Hernando]

    Hi,
    The following code was working properly in gcc 3.3.3, but is not 
working if I compile it with gcc 4.1.2., it gives a Segmentation 
Violation when it's run.
What the code does do is to generate assembler opcodes and then execute 
them directly as if they were a function, using a function pointer.
Following is a simplified version of the code:

#include <stdio.h>

typedef void  (*FunctionType)();

int main() {
    char *code = new char[5];
    int codeIndex = 0;
    printf("Start!!\n");

    code[codeIndex++]=0x55; //push %ebp
    code[codeIndex++]=0x89; //mov    %esp,%ebp
    code[codeIndex++]=0xe5;    //"

    code[codeIndex++]=0xc9; //LEAVE
    code[codeIndex++]=0xc3; //RET

    FunctionType invoke=(FunctionType)&code[0];
    invoke();

    printf("Finish!!\n");
    return 0;
}

    If this is compiled with gcc 3.3.3 it executes without any problem: 
prints "Start!!", then executes invoke(), which does nothing, as you can 
see (the assembler is just a call to an empty function), and finally it 
prints "Finish!!".
    But the problem happens when I compile this using gcc 4.1.2 (and the 
same happens with 4.2.2): prints "Start!!", and it gives a Segmentation 
Violation when it starts executing invoke (I've seen using the gdb that 
the SIGSEGV happens just in the first instruction, in the "push %ebp").
    I guess something related with this should have been changed from 
gcc 3.x to gcc 4.x, and I would like to know what is it, and if there's 
a problem to have this kind of code working in gcc 4.x
    Thank you very much.
    Kind regards,

    Anibal Caceres.