Cumulative summation unit

A method of cumulative summation of a series of numeric additives, each additive having a format and comprising a plurality of bit-sequences which make up said additive, said bit-sequences being presented in series, said method comprising the steps of:

• storing at least one cumulative summation running total (RTn) of the series of numeric additives;
• selecting from the plurality of bit-sequences in a predetermined order according to the format a first bit-sequence and selecting from the cumulative summation running total RTn according to the format a second bit-sequence corresponding to the first bit-sequence;
• receiving the first bit-sequence to form a first operand (O1) and the second bit-sequence to form a second operand (O1);
• adding the first and second operands to provide a result as a third bit-sequence;
• and
• updating the storage means (130) with the third bit-sequence.

A method of summation of two floating point format additives including the steps of:

• a) comparing exponent portions of each additive to identify a byte-shift value (46) and a bit-shift value (47);
• b) selecting a first mantissa byte from the first additive as a first operand (O1);
• c) selecting a corresponding byte from the second additive, the corresponding byte being selected according to the byte-shift value;
• d) bit-shifting the corresponding byte according to the bit-shift value to form a second operand (O2);
• e) performing an addition or subtraction operation on the first and second operands (O1, O2);
• and
• f) repeating steps b) to e) for successive mantissa bytes of each additive.