| 摘要 |
PURPOSE:To curtail the quantity of a hardware required for extending a code by generating a code and an extension code of a multiplicand inputted to a multi-input adder by a selecting signal from a decode of a booth and a code of an original multiplicand. CONSTITUTION:(n) pieces of decoders 1 fetch bits of a multiplier by three bits each and output a code (+ or -) conforming to an algorithm of a booth and an X0,X1,X2 instructing signal. (n) pieces of selectors 2 receive the code (+ or -) and the X0,X1,X2 instructing signal from these decoders 1, and generate a code and an extension code of a multiplicand. Also, the selector 2 is constituted so that the lower digit is shifted ot the right by two bits each from its upper digit. That is, the code and the extension code of the multiplicand inputted to the selector 2 are generated by a selecting signal (code+ or -and X0,X1,X2) given from a decoder 2 of the booth and a code of an original multiplicand X. In such a way, the quantity of a hardware required for extending the code can be curtailed. |
