| 摘要 |
PURPOSE: To prevent determination of the existence of preceding zero from being delayed by shifting the subtraction result of a subtractor in accordance with the leading zero prediction result of a leading zero predictor to execute required shift simultaneously with the completion of full subtraction. CONSTITUTION: In a normalizing device which determines the number of preceding zeros of the operation result from subtraction of an operand B from an operand A, operands A and B are stored in a register 10 and are supplied to a subtractor 70. Simultaneously with the calculation of a difference A-B in the subtractor 70, operands A and B are supplied to a preceding zero predictor 80 which determinates the accurate number of preceding zeros of the subtraction result. A first subtraction result 25 is shifted in a shifter 40 in accordance with a result 85 of the leading zero predictor 80 to output a result 60 directly and accurately normalized without using a normalizing corrector. The full subtractor 70 is so designed that is supplies a borrow signal 90 to the preceding zero predictor 80 as quickly as possible, and this supply is executed just before the full subtraction result is obtained. |
