METHOD/APPARATUS FOR CONVERSION OF HIGHER ORDER BITS OF 64-BIT INTEGER TO FLOATING POINT USING 53-BIT ADDER HARDWARE

A floating point unit capable of converting a 64-bit integer number to a floating point format is provided. The floating point unit includes an 11-bit zero/one complement detect circuitry in an exponent datapath of the floating point unit, where the 11-bit zero/one complement detect circuitry is used to determine a shift count for a right shifter in a large exponent difference mantissa datapath of the floating point unit. The 11-bit zero/one complement detect circuitry determines shift counts based on particular bit groupings of the 64-bit operand.