APPARATUS AND METHOD FOR FIXED POINT TO FLOATING POINT CONVERSION AND NEGATIVE POWER OF TWO DETECTOR

摘要

A data processing system 2 supports conversion of fixed point numbers to floating point numbers. The result floating point numbers may be subnormal. A first shifter 28 shifts input signals representing the fixed point number by a first shift amount depending upon a leading zero count within an integer portion followed by a fractional portion of the fixed point number. A second shifter 30 shifts the input signals by a second shift amount depending upon the variable point position within the fixed point number. A subnormal result detector 34 generates a selection signal in dependence upon detection of a combination of a variable point position and the count of leading zeros which corresponds to the floating point number having a subnormal value. Selection circuitry 32 selects one of the outputs from the first shifter or the second shifter to form the significand in dependence upon the selection signal generated by the subnormal result detector.