HP 68000 Series, User Manual

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Symbolic Referencing
The debugger references symbols in a different manner than the standard C
language definition. Therefore, understanding how variables are allocated and
stored in memory is important. The following sections describe symbol
storage classes and data types. These sections are followed by a discussion on:
•
R eferencing symbols with root, module, and function names.
•
Making stack references.
In the following paragraphs, the notion of a ’module’ is synonymous with a file
in C. In fact, the module name is simply the basename of the source file with
no suffix.
Storage Classes
All variables and functions in a C source program have a storage class that
defines how the variable or function is created and accessed. The storage
classes are:
•
extern (global)
•
static
•
automatic
•
register
C preprocessor symbols are not available to the debugger. The following
paragraphs describe each storage class used in a C source program.
Extern (global)
Global variables in a C program are declared outside of a function and are
accessible to all functions. Storage for these variables is allocated only once.
Thereafter, references are made to the previously allocated space.
Global functions can be called from any other function.
Static
Static variables in a C program are allocated permanent storage and can be
local to a module or local to a function.
Chapter 10: Expressions and Symbols in Debugger Commands
Symbolic Referencing
432