Bit length converting circuit for floating-point numbers, and vibration correction control circuit using the bit length converting circuit

Abstract

The bit length reducing unit reduces the bit length of an operand expressed by a floating-point number and outputs the operand to a computing unit. The bit length increasing unit increases the bit length of the result value of operation represented by the floating-point number inputted from the computing unit and restores the original bit length. The bit length reducing unit discards a preset number of higher-order bits of the exponent part of the floating-point number and at the same time adds a positive or negative offset value to the exponent part with the higher-order bits discarded, according to an application to be executed by the computing unit. The bit length increasing unit restores the bits discarded by the bit length reducing unitfrom the exponent part of the floating-point number and at the same time subtracts an offset value from the exponent part.