Floating point format converter

A computer program product for converting a binary floating point number represented in a binary floating point format to an equivalent decimal floating point number in a decimal floating point format, the binary floating point format having an associated first base value of two and being represented by a first significand value and a first exponent value, and the decimal floating point format having an associated second base value of ten and being represented by a second significand value and a second exponent value, comprising a non-transitory tangible computer readable storage medium storing an executable algorithm for causing a data processing system to perform the steps of:

• determining the second exponent value for the decimal floating point number by multiplying the first exponent value by a predefined constant and taking the integer portion of the result, the predefined constant being substantially equivalent to the logarithm of two divided by the logarithm of ten;
• determining a bias value that is substantially equivalent to two raised to the first exponent value divided by ten raised to the second exponent value, wherein the determination of the bias value includes:
• determining an intermediate bias value by addressing a look-up table with the second exponent value;
• and
• determining the bias value by applying a binary shift operation to the intermediate bias value, wherein a magnitude of the binary shift is determined responsive to the first exponent value;
• and
• determining the second significand value for the second floating point number by multiplying the first significand value by the bias value.

A floating-point unit including a floating point format converter for converting a binary floating point number represented in a binary floating point format to an equivalent decimal floating point number in a decimal floating point format, the binary floating point format having an associated first base value of two and being represented by a first significand value and a first exponent value, and the decimal floating point format having an associated second base value of ten and being represented by a second significand value and a second exponent value, comprising:

• a multiplier for determining the second exponent value for the decimal floating point number by multiplying the first exponent value by a predefined constant and taking the integer portion of the result, the predefined constant being substantially equivalent to the logarithm of two divided by the logarithm of ten;
• a look-up table unit for determining an intermediate bias value by addressing an intermediate bias look-up table with the second exponent value;
• a shift register for determining a bias value by applying a binary shift operation to the intermediate bias value, the magnitude of the binary shift being determined responsive to the first exponent value, wherein the determined bias value is substantially equivalent to two raised to the first exponent value divided by ten raised to the second exponent value;
• and
• a multiplier for determining the second significand value for the second floating point number by multiplying the first significand value by the bias value.