8. Program Loading and Running

Even after a program is written, compiled, and linked into an executable object file, there are still many tasks that need to be performed before the program does its job. The program must be loaded onto the target, memory and registers must be initialized, and the program must be set to running.

Some of these tasks need to be built into the program itself. Bootstrapping is the process of a program performing some of its own initialization. Many of the necessary tasks are handled for you by the compiler and linker, but if you need more control over these tasks, it helps to understand how the pieces are expected to fit together.

This chapter will introduce you to the concepts involved in program loading, initialization, and startup.

This chapter does not cover dynamic loading.

This chapter currently provides examples for the C6000 device family. Refer to your device documentation for various device-specific aspects of bootstrapping.

Table of Contents

• 8.1. Loading
  • 8.1.1. Load and Run Addresses
  • 8.1.2. Bootstrap Loading
    • 8.1.2.1. Boot, Load, and Run Addresses
    • 8.1.2.2. Primary Bootloader
    • 8.1.2.3. Secondary Bootloader
    • 8.1.2.4. Boot Table
    • 8.1.2.5. Bootloader Routine
• 8.2. Entry Point
• 8.3. Run-Time Initialization
  • 8.3.1. The _c_int00 Function
  • 8.3.2. RAM Model vs. ROM Model
    • 8.3.2.1. Autoinitializing Variables at Run Time (--rom_model)
    • 8.3.2.2. Initializing Variables at Load Time (--ram_model)
    • 8.3.2.3. The --rom_model and --ram_model Linker Options
  • 8.3.3. About Linker-Generated Copy Tables
    • 8.3.3.1. BINIT
    • 8.3.3.2. CINIT
• 8.4. Arguments to main
• 8.5. Run-Time Relocation
• 8.6. Additional Information