Abstract: A processor to calculate a floating-point dot-product that receives a sequence of first and second floating-point numbers in which the sequence of the first and second floating-point numbers having a sign, a mantissa value and an exponent value. A floating-point unit determines the floating-point dot-product of the sequences by adding the exponent values to determine an exponent product, calculating a shift amount as a one's complement of a low exponent, multiplying the mantissas of the sequences to determine a product value of the mantissas, right shifting the product value of the mantissa by the shift amount to generate a shifted product, selecting segments of an accumulator based on a high exponent, and adding the selected segments to the shifted product to generate a sum. The sum is then written into the selected segments of the accumulator.

Abstract: Techniques are presented to improve the speed of calculating floating-point dot-products, such as in a floating point unit (FPU). Rather than determine the full maximum exponent initially and wait until the full individual shift amounts are calculated to right-shift each mantissa product, each product of exponents is divided into two fields, a high field and a low field. The low field is used as a fine-grained shift amount to right-shift each mantissa product as soon as the mantissa product is ready, while only hi field participates in the maximum exponent calculation. This allows a dot-product computation to be speed up in two ways: Right-shifting of the mantissa product can begin as soon as the mantissa products are calculated, without waiting for the maximum exponent calculation; and calculation of the maximum exponent is sped up because it is calculated only on the high fields of the exponent, not its full-width.

Abstract: A circuit (10) for multiplying two floating point operands (A and C) while adding or subtracting a third floating point operand (B) removes latency associated with normalization and rounding from a critical speed path for dependent calculations. An intermediate representation of a product and a third operand are selectively shifted to facilitate use of prior unnormalized dependent resultants. Logic circuitry (24, 42) implements a truth table for determining when and how much shifting should be made to intermediate values based upon a resultant of a previous calculation, upon exponents of current operands and an exponent of a previous resultant operand. Normalization and rounding may be subsequently implemented, but at a time when a new cycle operation is not dependent on such operations even if data dependencies exist.

Abstract: A circuit (10) for multiplying two floating point operands (A and C) while adding or subtracting a third floating point operand (B) removes latency associated with normalization and rounding from a critical speed path for dependent calculations. An intermediate representation of a product and a third operand are selectively shifted to facilitate use of prior unnormalized dependent resultants. Logic circuitry (24, 42) implements a truth table for determining when and how much shifting should be made to intermediate values based upon the a resultant of a previous calculation, upon exponents of current operands and an exponent of a previous resultant operand. Normalization and rounding may be subsequently implemented, but at a time when a new cycle operation is not dependent on such operations even if data dependencies exist.