MRM_CRT0
<ol>
<li>define .data
<li>define __unhandled_exception et al.
<li>define .text
<li>set things up so the application will run. This *must* be called start
<li>if the user provided us with flags (symbol name 'crt0_flags') for the startup code, load them now.  If not, use defaults.
<li>if user provided an initialization list, process it now this is typically used to set up hardware that is critical to system operation,
 for example chip selects, watchdog timers, etc.
<li>See if user supplied their own stack (__stack != 0). If not, then leave it as set by the ROM monitor/exception vector. [note: stack is provided]
<li> if the user provided a hardware init function, call it now.  this is done first so that hardware is all set up for the rest of crt0 [NOTE: no hook provided]
<li>If bit 0 of crt0_flags is set, then do a jump to the init routine with the return address in D0; otherwise do a normal jsr. [NOTE: bit not set]
<li>If bit 1 of crt0_flags is clear, then zero out the bss section.  [NOTE: bit IS clear]
<li> copy .data image, if there is one, from ROM to RAM.
<li>if ADD_DTORS defined then put __do_global_dtors in the atexit list so the destructors get run.
<li> call the main routine from the application to get it going. applications executes, and terminates somehow
<li> drop down into exit incase the user doesn't. This should drop control back to the ROM monitor, if there is one. This calls the
 exit() from the C library so the C++ tables get cleaned up properly.
<li>Lastly, we define a default handler for exceptions not otherwise handled in the application code.
</ol>