library IEEE;  
  use IEEE.Std_Logic_1164.all;

entity wire_delay is
  generic(a_to_b_loss : time := 1 ns;
          b_to_a_loss : time := 2 ns);
  port
    (A : inout Std_Logic;
     B : inout Std_Logic
     );
end wire_delay;

architecture behave of wire_delay is
begin

  ABC0_Lbl: process
    variable ThenTime_v : time := 0 ns;

    function max(t1,t2 : time) return time is
    begin
        if (t1 > t2) then
          return t1;
        else
          return t2;
        end if;
    end;

  begin
    wait on A'transaction, B'transaction
                      until ThenTime_v + max(a_to_b_loss, b_to_a_loss) < now;
    -- Break
    ThenTime_v := now;
    A <= 'Z';
    B <= 'Z';
    wait for 0 ns;

    -- Make
    A <= transport B after b_to_a_loss;
    B <= transport A after a_to_b_loss;

  end process ABC0_Lbl;
end behave;