Microprocessors constitute one of the most important classes of VLSI chips. Over the last 25 years their architectures and capabilities have evolved rapidly to pack enormous computing power in them. However, this has made the task of designing successive generations of microprocessors increasingly complex. Methodologies used to design microprocessors have also accordingly changed from generation to generation. The purpose of this paper is to summarize these evolutions in architecture and design methodologies of microprocessors and present a microprocessor design example using a methodology that makes efficient use of the HDL-based design approach to create portable microprocessor designs for use in system-level integrated products.