2.1 Introduction

In this chapter, we begin our study of microprocessors by studying instruction sets—the programmer’s interface to the hardware. Although we hope to do as much programming as possible in high-level languages, the instruction set is the key to analyzing the performance of programs. By understanding the types of instructions that the CPU provides, we gain insight into alternative ways to implement a particular function.

We use four CPUs as examples. The ARM processor [Fur96, Jag95, Slo04] is widely used in cell phones and many other systems. (The ARM architecture comes in several versions; we will concentrate on ARM version 7.) The PIC16F is an 8-bit microprocessor designed for very efficient, low-cost implementations. The Texas Instruments C55x and C64x are two very different digital signal processors (DSPs) [Tex01, Tex02, Tex10]. The C55x has a more traditional architecture while the C64x uses very-long instruction word (VLIW) techniques to provide high-performance parallel processing.

We will start with a brief introduction to the terminology of computer architectures and instruction sets, followed by detailed descriptions of the ARM, PIC16F, C55x, and C64x instruction sets.