tic tac toe

I have not taken the time to set up a simulation, but as for the line 69 error I have an answer.

When the following block executes:

  if D_in = "11" then	
    C <= 0;
  elsif C < n-1 then
    C <= C + 1;
end if;

C can equal n.

This is an issue since:

.
  signal memory_last_row : std_logic_vector (0 to 2*n-1) ;	 -- because D_in has 2 bits the memory needs to be 2*D_in
  signal changed_chk     : std_logic_vector (0 to n-1) ;
.
.
  memory_last_row(2*C)    <= D_in(1);
  memory_last_row(2*C+1)  <= D_in(0);

Assume n = 3, so C = 3 after the execution of C < n if statement. When you calculate the declared size of the signal memory_last_row (2*3-1 = 5) and the index you are trying to select (2*3 = 6), you are out of bounds.