| 摘要 |
PURPOSE:To curtail the quantity of a hardware and to attain a high speed by executing the substantial part of an addition only in a column in which an augend and an addend are present and adding a carry after a next step. CONSTITUTION:A first means for executing an intermediate addition in which the augend and the addend are present, a second means for saving the addition in a part in which one number, namely either the augend or the addend is present and making the other number namely, the addend or the augend directly a sum, a third means for storing the carry generated according to the addition of the first means and adding in the addition after the next step and a fourth means for directly outputting externally a part in which one low order number, namely, only the augend or the addend is present from a part in which the columns are overlapped are provided. To the addition of numbers except a number in which the most significant column of the respective steps of an addition tree is situated at the lowest order and a number in which it is situated in the order next to the lowest order, the addition of the two numbers is simultaneously executed by the first - the third means to obtain the sum. Thereby, the quantity of the hardware is curtailed and the high speed is attained. |
