🚀 go-pugleaf

Given the following architecture body.
D and E are converted to correct values, but F gives a 0.
Any ideas why this doesn't work (especially since it works elsewhere)?

architecure adder of adder is
 signal d,e,f : integer;
 begin
  process (add_enable, add_in1, add_in2)
    if (add_enable, = '1') then
      d <= bin_int2(add_in1); -- convert 32-bit bit array to integer 
      e <= bin_int3(add_in2); -- convert 40-bit bit array to integer 
      f <= (d + e); -- add the integers together
    end if;
  end process;
end adder;