| 摘要 |
An apparatus and method for generating a sum of floating point input values are provided. To sum the values, multiple partial sum floating-point values are maintained and the partial sum to which an input value may be added is selected 62 in dependence upon a least significant portion of the exponent of the input value. If, when compared, the exponent of the input value is equal 64 to the exponent of the value stored in the selected partial sum, a mantissa sum of the input value and stored partial sum value replaces 66 the mantissa value of the selected partial sum value. If the exponent of the input value is larger, the selected partial sum value is replaced 68 with the input value. If the exponent of the input value is smaller, the selected partial sum value may be left unmodified 72. An associative and deterministic summation is thus provided: the final result 76 is ultimately independent of the order of accumulation of the input values. An intermediate format 60 may be used, which may have a larger encoding space than the input format; this may comprise a smaller expressible exponent range and a larger expressible mantissa range. |
