Abstract: The present invention relates to a method and circuit for performing multiply-operations in an arithmetic unit of a computer processor. In a multiplier thereof, zero detection of the resulting product bit string (22) is needed for a proper setting of condition code and overflow status information. Zero detection according to prior art decreases the calculation speed in the multiplier. In order to provide a method and respective electronic circuit, wherein the zero detection is earlier completed, it is proposed to use a leading zero anticipation (LZA) hardware—i.e., an LZA circuit (40), which exists usually anyway in floating point processor adders for calculating the number of leading zeros for operand normalization purposes—for performing a zero detection of the product by aid of the partial results (16, 17) emerging at the output of the Wallace tree of the multiplier.

Abstract: A method of determining a biased leading-zero count for a floating-point operation is disclosed. First, a binary vector is divided into subvectors. Then, multiple subvector leading-zero counts are generated. The subvector leading-zero counts are biased by a constant amount. Next, one or more prefix bits are calculated. Finally, at least a portion of a selected subvector leading-zero count is concatenated to the prefix bits to yield a total leading-zero count for the binary vector.