>>>>> "Tyrel" == Tyrel Beede <tb90@mail.csuchico.edu> writes:

  Tyrel> I read the important information in the "Design and Implementation of
  Tyrel> the UVM"... really an amzing docuement.  Anyway, a little bit more on
  Tyrel> topic I was wondering about the trap.c source and if it really needed
  Tyrel> all of the #ifdef stuff to determine if the code should run for the sh3
  Tyrel> or the sh4 cpu.  It looks kinda ugly and I was wondering why would
  Tyrel> prevent this from being cleaned up?  Also from the code it looks like
  Tyrel> the general register r15 is used for a special purpose?  Does it hold
  Tyrel> the base address of the PDT or something?

I'll leave the #ifdef question to someone who has a better
understanding of sh3, I'm sh4 only.

r15 is the stack pointer.  That's a pretty special purpose, yes.  :)

  // Marcus