1. An integrated circuit device comprising: at least one instruction processing module arranged to receive a bit-manipulation instruction, and in response to receiving the bit-manipulation instruction to select at least one bit from at least one source data register in accordance with a value of at least one control bit, select from candidate values a manipulation value for the at least one selected bit in accordance with a value of at least one further control bit, and store the selected manipulation value for the at least one selected bit in at least one output data register.