| 摘要 |
PURPOSE:To reduce the number of hardware required for making addition to the utmost, by materializing the same multiplying system as that made by calculation with fingers written down on paper by means of hardware. CONSTITUTION:The a, b, c, and d of the diagram represent input data for multiplication corresponding to Formula I . The carry of (bXd) and (aXd+G) are performed by G-output and ROM13, respectively. Similarly, (aXc+F) is performed by an ROM11. Results CDE and ABf on the midway of the multiplication are outputted from ROMs 11 and 12 and ROMs 13 and 14, respectively. Then addition is performed on the results on the midway of calculation. First, addition of the lower-order digit E of the result of (bXc) to the low-order digit B of the result of (aXd+G) is performed by an adder 17. Then addition of the low order digit D of the result of (aXc+F) to the high-order digit A of the result of (aXd+G) is performed by an adder 16. Then addition of the high- order digit C of the result of (aXc+F) to outputs H, I, and J of adders 16 and 17 is performed by an adder 18 and addition of the higher digit K of the result of the addition to the output C of the ROM11 is performed by an adder 15. As a result, the final result of the multiplication wxyzf is obtained. |
