I have code :
#include <iostream>
void fun(double _v)
{
    std::cout<<"_v="<<_v<<std::endl;
    long long int var=static_cast< long long int >(_v*1000.);
    std::cout<<"var="<<var<<std::endl;
}
int main(int ac, char** av)
{
    fun(33.33);
    return 0;
}
I try to compile this code on Linux x86_64 with GCC 4.8.2 (g++ test.cpp -o test64), I get result in console:

_v=33.33
var=33330

but when I try to compile this code on Linux i686 with GCC 4.8.2 (g++ test.cpp -o test32), I get result in console:

_v=33.33
var=33329

But if I replace "long long int var=static_cast< long long int >(_v*1000.);" to "double t = _v*1000.; long int var=static_cast< long long int >(t);" I get the result on Linux i686 with GCC 4.4.5:

_v=33.33
var=33330