4.4 Symbols

A symbol represents a value and can be comprised of one or more characters chosen from the set composed of all letters, digits, the underline character (_), and the period (.). Symbols may not begin with a digit. The case of the letters is significant (for example, foo is a different symbol than Foo). There is no length limit and all characters are significant.

Each symbol has exactly one name. Each name in an assembly language program refers to exactly one symbol. You may use that symbol name any number of times in a program.