4.3.7 Specifying the Type of Global Variable Initialization

The C/C++ compiler produces data tables for initializing global variables. Section 6.9.3.4 discusses the format of these initialization tables. The initialization tables are used in one of the following ways:

• Global variables are initialized at run time. Use the --rom_model linker option (see Section 6.9.3.3).
• Global variables are initialized at load time. Use the --ram_model linker option (see Section 6.9.3.5).

If you use the linker command line without compiling any C/C++ files, you must use either the --rom_model or --ram_model option. These options tell the linker two things. First, they indicate that the linker should follow C/C++ conventions, using the definition of main() to link in the c_int00 boot routines. Second, they tell the linker whether to select initialization at run time or load time. If your command line fails to include one of these options when it is required, you will see "warning: no suitable entry-point found; setting to 0".

If you use a single command line to both compile and link, the --rom_model option is the default. If used, the --rom_model or --ram_model option must follow the --run_linker option (see Section 4.1).

For details on linking conventions for EABI with --rom_model and --ram_model, see Section 6.9.3.3 and Section 6.9.3.5, respectively.