| 摘要 |
PURPOSE:To increase the arithmetic speed as compared with a conventional device and to simplify the circuit configuration by constituting a polarity converting means with rounding processes by using only one adding means as to the numerical expression conversion device which can perform two kinds of rounding process. CONSTITUTION:A 1st bit inverting circuit 8 inverts the bits of the integer part of a numeral obtained by a shifter 2 which functions as a decimal-point positioning means and sends out the inversion result. The output of this inverting circuit 8 is supplied to one input of an adding circuit 11. An AND circuit 9 ANDs the detection signal B and rounding-off direction command signal C from the overflow numeral presence/absence detection part 2a of the shifter 2. The output of the AND circuit 9 is further inverted by a 2nd bit inverting circuit 10 and then inputted to the other input of the adding circuit 11 as a carry-up numeral. The adding circuit 11 adds the output values of the 1st and 2nd bit inverting circuits 8 and 10 and supplies the sum to a selector 6 as a negative numeral in fixed point representation to be outputted finally. |
