architecture behavioral of accumulator_adder is begin behavior : process (a, b) is constant Tpd_in_out : time := 3 ns; variable carry_in : std_ulogic; variable carry_out : std_ulogic := '0'; begin for index in 0 to 21 loop carry_in := carry_out; -- of previous bit s(index) <= a(index) xor b(index) xor carry_in after Tpd_in_out; carry_out := (a(index) and b(index)) or (carry_in and (a(index) xor b(index))); end loop; ovf <= carry_out xor carry_in after Tpd_in_out; -- ovf is carry_out /= carry_in end process behavior; end architecture behavioral; <div align="center"><br /><script type="text/javascript"><!-- google_ad_client = "pub-7293844627074885"; //468x60, Created at 07. 11. 25 google_ad_slot = "8619794253"; google_ad_width = 468; google_ad_height = 60; //--></script> <script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js"> </script><br /> </div>