...

Initial instruction

• Execution after reset starts at 0xfffffffc
  • A branch instruction (either b or ba; 26 bit range) to some boot code is loaded here
    • The Xilinx example branches to in block RAM (bram) at 0xffffff00
    • The RTEMS example branches to download_entry (but I'm not sure how)
  • Potentially a sc (system call) instruction could be loaded here? Any advantage to this?
    • Probably not as the corresponding ivor register (PPC 440) is not loaded yet
    • The PPC 405 doesn't have ivor registers, so it would continue executing at the system call vector

...

• Command line is in the first and only argument
  • In our system this is always a null pointer
• Disable interrupts
• Store command line
• Call bsp_start()
• Determine RTEMS work area and heap location and size
• Initialize RTEMS data structures
• Initialize the C library
  • This also installs the heap
• Call bsp_pretasking_hook()
• Wiki Markup\[Enable RTEMS debugging capabilities\]
• RTEMS initialization before loading device drivers
• Call bsp_predriver_hook()
• Initialize device drivers
• Call bsp_postdriver_hook()
• Start multitasking
  • Before starting the first task call any C++ static constructors.
  • Thread with entry point Init runs
  • Not clear how this returns. Perhaps when the last task is deleted?
• Call bsp_cleanup()
• Return to the start code
  • Not clear what's in the lr at this point, i.e., where do we return to?

...

• Announce what's running
• Configure the network from DHCP
• Set up the dynamic linkerunmigrated-wiki-markup
• \[Start the shell\]unmigrated-wiki-markup
• \[Start the debugger daemon ({{gdb}} stub)\]
• Create a Task
• Determine what the Task should run
  • Read metadata from flash
  • Read the front panel rotary switch
• Dynamically link the code
• Run the Task