Hacking Notes:

- Memory_Retr (and Memory_Retr*) DO NOT do any sign extension.
   8 bit read on FFFFFFFF returns 000000FF.
   
- EA_GetValue does do sign extenstion.
   8 bit read on xxxxxxF0 returns FFFFFFF0.
   
- Any jump address in the VBR that is FFFFFFFF (ie, way up in ROM on the real
   coldfire).. will be passed to Monitor_HandleException(Vector).  This 
   includes things like the TRACE exception (#9).  So yes, you can override
   any exception handler (just like in the real thing).

- Our dBug (a dBUG clone) runs completely on exceptions.. the only way to get
   into dBug is through an exception.


