Generation of exponent values

A separate comparing unit 618 is configurable to compare exponent values and to store one of said pair of exponent values dependent upon the result of said comparison. This comparison value then remains available for subsequent operations performed by associate circuitry, including arithmetic logic units 605, 606 and a normalisation circuit 619. The normalisation circuit determines the extent to which associate mantissa require shifting operations to be performed in order to normalise a block of floating point values. Processing elements are controlled by clocking some on rising edges of clock pulses, some on falling edges and some on both.