Abstract: A data processor executes a table look-up and interpolate instruction which retrieves two adjacent table values from memory, interpolates between them and stores the result in a register. The same register contains, prior to the execution of the instruction, a value which is used both in calculating the address in memory from which the values are obtained and in performing the interpolation calculation. A major variant of the instruction involves obtaining the values to be interpolated between from registers, rather than from a table in memory. The combination of the two facilitates the performance of three-dimensional, or surface interpolations. It is also possible to select whether rounding is performed during the interpolation.