Antonelli, Terry, Stout & Kraus, LLP
Arithmetic unit capable of performing concurrent operations for high speed operation
 An arithmetic unit which accepts two numerical values and executes an operation by the use of the two numerical values; has an adder-subtracter for executing an addition or a subtraction on the basis of two numerical values obtained directly or indirectly from the accepted two numerical values; a normalizer for executing a normalizing process in which a mantissa part of an added or subtracted result is shifted so that a high-order digit having been developed anew in the result may come to a predetermined position, and in which an exponent part of the result is corrected in accordance with the number of shift places in the shift of the mantissa part; and a rounding device for executing a rounding process in which, on condition that the mantissa part of the added or subtracted result exceeds a predetermined number of digits, the number of digits of the mantissa part is reduced in conformity with a rounding mode designated beforehand. The rounding device executes at least part of the rounding process by the use of the numerical values not yet subjected to the normalizing process, in parallel with the execution of the adder-subtracter or the normalizer. 
Hitachi, Ltd.
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Hiromichi Kotaro Takashi Hidehito
Yamada Shimamura Hotta Takewa