System and method for instruction set conversion based on mapping of both block address and block offset

An instruction set conversion system and method is provided, which can convert guest instructions to host instructions for processor core execution. Through configuration, instruction sets supported by the processor core are easily expanded. A method for real-time conversion between host instruction addresses and guest instruction addresses is also provided, such that the processor core can directly read out the host instructions from a higher level cache, reducing the depth of a pipeline.