Before revision: Two's complement (negate) : A (or B) is subtracted from zero and the difference appears at Y. Increment: A (or B) is increased by one and the resulting value appears at Y. Decrement: A (or B) is decreased by one and the resulting value appears at Y.
After revision: Two's complement : A (or B) is subtracted from zero and the difference appears at Y. Increment: A (or B) is increased by one and the resulting value appears at Y. Decrement: A (or B) is decreased by one and the resulting value appears at Y.