hi there, pls how could I write the code for a 64 bit adder in such a way that I dont have to do something like this 64 times: sum(0) <= A1(0) XOR A2(0) ; carry(0) <= A1(0) AND A2(0) ; sum(1) <= A1(1) XOR A2(1) XOR carry(0) ; carry(1) <= (A1(1) AND A2(1)) OR (A1(1) AND carry(0)) OR (A2(1) AND carry(0)) ; (thats with reference to the addaccu tutorial) Thanks GIIE --------------------------------- Do You Yahoo!? Send FREE Valentine eCards with Yahoo! Greetings!