A simple processor
The 6502 processor architecture and a small subset of its instructions were introduced in Chapter 1, Introducing Computer Architecture. In this section, we will build upon that foundation to present some of the functional components universally employed in processor architectures, from the tiniest embedded controllers to the most powerful server CPUs.
The integrated circuit at the core of a computer system goes by a few different names: the Central Processing Unit (CPU), microprocessor, or, simply, processor. A microprocessor is a single integrated circuit that implements all the functions of a processor. This book will refer to all categories of CPUs and microprocessors as processors.
A processor like the 6502 contains three logically distinct functional units:
