Programmable signal and processing circuit and method of depuncturing

A programmable signal processing circuit has an instruction processing circuit (23, 24, 26), with an instruction set that comprises a depuncture instruction. The instruction processing circuit (23, 24, 26) forms the depuncture result by copying bit metrics from a bit metrics operand and inserting one or more predetermined bit metric values between the bit metrics from the bit metric operand in the depuncture result. The instruction processing circuit (23, 24, 26) changes the relative locations of the copied bit metrics with respect to each other in the depuncture result as compared to the relative locations of the copied bit metrics with respect to each other in the bit metric operand, to an extent needed for accommodating the inserted predetermined bit metric value or values.