A half adder takes two binary inputs and generates ... Now we have the final full adder circuit design. As nice as this design appears, it is not practical as an accumulator, e.g. a register ...

This is the groundwork for the half adder . The next step is the operational logic, which of course falls upon macros: /* Full adder macros */ /* Out = (A ^ B) ^ cin */ #define FULL_ADD_OUT( a ...