Texas Instruments TMS320C2x, User Manual

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Controlling the Linking Process
4-9 Linking C Code
Note: The _c_int0 Symbol
One important function contained in the run-time-support library is _c_int0.
The symbol _c_int0 is the starting point in boot.obj; if you use the
− c or − cr
linker option, _c_int0 is automatically defined as the entry point for the
program. If your program begins running from reset, you should set up the
reset vector to branch to _c_int0 so that the processor executes boot.obj first.
The boot.obj module contains code and data for initializing the run-time envi-
ronment. The module performs the following tasks:
1) Sets up the stack
2) Processes the run-time initialization table and autoinitializes global
variables (when using the − c option)
3) Calls main
4) Calls exit when main returns
Chapter 7 describes additional run-time-support functions that are included in
the library. These functions include ANSI C standard run-time support.
4.5.2 Specifying the Type of Initialization
The C compiler produces data tables for initializing global variables. Section
6.8.3,
Initialization Tables , on page 6-33 discusses the format of these tables.
These tables are in a named section called .cinit . The initialization tables are
used in one of the following ways:
-
Global variables are initialized at run time . Use the − c linker option (see
section 6.8.4, Autoinitialization of Variables at Run Time , on page 6-34).
-
Global variables are initialized at load time . Use the − cr linker option (see
section 6.8.5, Initialization of Variables at Load Time , on page 6-35).