| 摘要 |
An apparatus and method are provided for performing an addition operation on operands A and B in order to produce a result R, the operands A and B and the result R being floating point values each having a significand and an exponent. The apparatus comprises prediction circuitry for generating a shift indication based on a prediction of the number of leading zeros that would be present in an output produced by subjecting the operands A and B to an unlike signed addition. Further, result pre-normalization circuitry performs a shift operation on the significands of both operand A and operand B prior to addition of the significands, this serving to discard a number of most significant bits of the significands of both operands as determined by the shift indication in order to produce modified significands for operands A and B. Operand analysis circuitry detects, with reference to the exponents of operands A and B, the presence of a leading bit cancellation condition, and addition circuitry is configured, in the presence of the leading bit cancellation condition, to perform an addition of the modified significands for operands A and B, in order to produce the significand of the result R. Such an approach provides a particularly simple and efficient apparatus for performing addition operations. |
