Initialize components with an internal ID

Question

I should create a structure (entity "A") composed of N components (entities "B"). Each component has several inputs and outputs and an internal signal ID (must be static), that identificates the component from 0 to N-1. Each component perform some operation based on ID. My problem is how to attribuite a static ID to each component at initialization time (during the port mapping). Obviously the components are "created" in for..generate loop, because N could be generic.

Answer 1

Declare a generic for your components, assign it the loop index of the generate, and, internally, assign the generic to the signal:

entity insider is
  generic(id: natural);
  port(
    ...
  );
end entity insider;

architecture arc of insider is
  signal s: natural;
begin
  ...
  s <= id;
  ...
end architecture arc;

...

architecture arc of outsider is
  ...
begin
  ...
  g: for i in 1 to 10 generate
    i: entity work.insider
      generic map(id => i)
      port map(
        ...
      );
  end generate g;
  ...
end architecture arc;