Abstract: The present invention discloses an apparatus for removing unnecessary instruction and method thereof. The apparatus and operating method thereof include: a comparing circuit for comparing a plurality of instructions and a predetermined pattern, so as to generate a plurality of comparing signals; a control logic for generating an instruction-selecting signal and a stride signal according to the plurality of comparing signals; and a multiplexer for receiving the plurality of instructions and outputting at least one of the received instructions to a processing unit according to the instruction-selecting signal. Furthermore, the processing circuit processes the instruction outputted by the multiplexer according to the stride signal.

Abstract: The present invention discloses a method for compressing instruction codes. This method comprises: compressing an instruction block including a plurality of instructions according to Huffman-Encoding technique; determining whether it's necessary to insert no-operation (nop) instructions among the plurality of compressed instructions according to a compression ratio, so as to generate a plurality of new instruction blocks conforming with the compression ratio; if it's necessary to insert nop instructions, inserting nop instructions among the plurality of compressed instructions to form the plurality of new instruction blocks; and repeating the above-mentioned steps until no nop instructions have to be inserted.