Data processing apparatus and method for multiplying floating point operands

A method of operating a data processing apparatus to multiply first and second normalized floating point operands in order to generate a result, each normalized floating point operand comprising a significand and an exponent, the method comprising:

• computing a result exponent for a normalized version of the result;
• generating a rounding value by shifting a rounding constant in a first direction by a shift amount that is dependent on the result exponent;
• multiplying the significands of the first and second normalized floating point operands to generate first and second partial products;
• adding the first and second partial products and the rounding value to generate a normalized result significand;
• and
• shifting the normalized result significand in a second direction opposite to said first direction, by said shift amount in order to generate a rounded result significand.

A data processing apparatus for multiplying first and second normalized floating point operands to generate a result, each normalized floating point operand comprising a significand and an exponent, the data processing apparatus comprising:

• exponent determination means for computing a result exponent for a normalized version of the result;
• rounding value generation means for generating a rounding value by shifting a rounding constant in a first direction by a shift amount that is dependent on the result exponent;
• partial product generation means for multiplying the significands of the first and second normalized floating point operands to generate first and second partial products;
• adder means for adding the first and second partial products and the rounding value to generate a normalized result significand;
• and
• shifting means for shifting the normalized result significand in a second direction opposite to said first direction, by said shift amount in order to generate a rounded result significand.