Performance hit of vtable lookup in C++

Question

I\'m evaluating to rewrite a piece of real-time software from C/assembly language to C++/assembly language (for reasons not relevant to the question parts of the code are ab

Answer 1

This is unrelated to your question, but if you are that keen on performance you could use templates to do a loop unroll for the todolist:

void (*todo[3])(void *);
void *param[3];

void f1(void*) {std::cout<<"1" << std::endl;}
void f2(void*) {std::cout<<"2" << std::endl;}
void f3(void*) {std::cout<<"3" << std::endl;}

template
struct Obj {
    static void apply()
    {
        todo[N-1](param[N-1]);
        Obj::apply();
    }
};

template<> struct Obj<0> { static void apply() {} };

todo[0] = f1;
todo[1] = f2;
todo[2] = f3;

Obj::apply();