| 摘要 |
PURPOSE:To discriminate the sign of a signed digit number by providing a first n-bit ((n) is a positive integer) shift register a second n-bit shift register, and a first coming signal discriminating the circuit to which the most significant bit of each register is inputted. CONSTITUTION:When one digit of the signed digit number is expressed with a pair of bits in the same positions of first and second n-bit shift registers 1 and 2, -1, 0, and +1 of each digit of the signed digit number are expressed with (1, 0), (0, 0), and (0, 1) respectively. First bits and second bits between parentheses are held in registers 1 and 2 respectively. When two registers 1 and 2 are simultaneously left shifted repeatedly, the most significant bit of the n-bit shift register having upper non-zero bits goes to '1' before that of the other n-bit shift register goes to '1'. This state is detected by a first coming signal discriminating circuit 8 to discriminate whether the most significant non-zero digit of the signed digit number is -1 or +1, and thus, the sign is discriminated with the simple constitution to facilitate design. |
