Surely that's just normal floating point but missing e.g. normalisation? Floating point is literally an int exponent and an int mantissa. Except real floating point adjusts the exponent to avoid integer overflow in the mantissa - which is where rounding happens.
In DPA the mantissa just overflows (silently in the C implementation) and then what?
In DPA the mantissa just overflows (silently in the C implementation) and then what?