The FMAC family of operations adds to the potential overflow range by generating significand values from zero up to but not including four. In this case it is possible for the final exponent to require incrementing by two to normalize the significand.

The bounce thresholds for the FADD family in Table 23.8 and for the FMUL family in Table 23.9 incorporate this additional factor. Those ranges are used to detect potential exceptions for the FMAC family.