a data processor for execution of tagged data and tagless data has a decoder for discriminating whether the data is tagged or tagless one and in case of a tagged data , separates a tag part and uses the remaining part for address computation . the data processor also comprises a unit for evaluating the tag part and a micro program controller for multi - branching in accordance with the evaluation result of the tag part . the tag evaluating unit includes an extender eliminating part for extracting the tag part from data on a data bus , a plurality of tag part storing registers for storing the tag part from the eliminating part under the control of the micro program controller , and a tag multi - way jump encoder for generating a tag multi - way jump address to feed it to the controller on the basis of the outputs of the registers and a signal from the micro program controller , thereby enabling tag multi - way jump .