Chapter 2: Data Representation

Download CD Content

2.1 Chapter Overview

A major stumbling block many beginners encounter when attempting to learn assembly language is the common use of the binary and hexadecimal numbering systems. Many programmers think that hexadecimal (or hex^[1]) numbers represent absolute proof that God never intended anyone to work in assembly language. While it is true that hexadecimal numbers are a little different from what you may be used to, their advantages outweigh their disadvantages by a large margin. Therefore, understanding these numbering systems is important because their use simplifies other complex topics including bit operations, signed numeric representation, character codes, and packed data.

This chapter discusses several important concepts including the binary and hexadecimal numbering systems, binary data organization (bits, nibbles, bytes, words, and double words), signed and unsigned numbering systems, arithmetic, logical, shift, and rotate operations on binary values, bit fields, and packed data. This is basic material, and the remainder of this text depends upon your understanding of these concepts. If you are already familiar with these terms from other courses or study, you should at least skim this material before proceeding to the next chapter. If you are unfamiliar with this material or only vaguely familiar with it, you should study it carefully before proceeding. All of the material in this chapter is important! Do not skip over any material. In addition to the basic material, this chapter also introduces some new HLA statements and HLA Standard Library routines.

^[1]Hexadecimal is often abbreviated as hex even though, technically speaking, hex means base 6, not base 16.