Fuente: Wipo "digitalization" A data processing apparatus to perform a digit-recurrence operation on an input value comprises receiver circuitry for receiving a remainder value of a previous iteration of the digit-recurrence operation. Comparison circuitry performs comparisons on most significant bits of the remainder value of the previous iteration of the digit-recurrence operation with each of a plurality of selection constants associated with available digits of a next digit of a result of the digit-recurrence operation and outputs the next digit of the result of the digit-recurrence operation based on the comparisons. Each of the selection constants is associated with one of the available digits and an input parameter. Storage circuitry stores a subset of the selection constants, the subset of the selection constants excluding an excluded selection constant from the selection constants, which is associated with an excluded digit from the available digits.