1. A method of operating a graphics system, wherein the method comprises: receiving an input; performing a scale and bias operation on the input to generate an output value, wherein said performing the scale and bias operation comprises: if the input is within a first range of inputs: inhibiting performance of a calculation on the input to generate the output value; and generating the output value equal to a first output value associated with the first range of inputs; and if the input is not within the first range of inputs, performing the calculation on the input to generate the output value.