The parallel full adder used to increment, decrement and subtract

Discussion in 'Homework Help' started by Jason87, Dec 11, 2009.

  1. Jason87

    Thread Starter Member

    Dec 10, 2009
    Figure attached uses the full adder whose inputs are defined as A and B. Given two external 3 bit registers X and Y i must use a truth table to show how the functions increment, (X+1), decrement, (X - 1) and subtract (X - Y) are obtained, together with add, (X + Y), using the adder under the control of signals s0 and s1? Any possible help?
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    What is the nature of the help you are looking for? Do you not understand binary arithmetic? Or do you not understand how to construct a truth table?