Circuitry comprises: a set of bit processing circuitries to apply two or more successive instances of bitwise processing to an ordered bit array; each bit processing circuitry for a given bit position within the ordered bit array comprising: bit shifting circuitry to selectively apply a bit shift of a respective input bit to a next bit processing circuitry in a first direction relative to the ordered bit array, in response to an active state of a bit shift control signal, the bit shifting circuitry not applying the bit shift in response to an inactive state of the bit shift control signal; and bit shift control circuitry to selectively allow or inhibit a bit shifting operation in response to one or more inhibit control signals; in which: the bit shift control circuitry is configured to selectively propagate an output inhibit control signal, indicating that a bit shifting operation should be inhibited, as an inhibit control signal to bit processing circuitry applying a next instance of the bitwise processing at the given bit position, in dependence upon the bit shift control signal and the one or more inhibit control signals.