Re: RFA: Mark DIVS and DIVU SH2A instructions as unusable in delayslots

[Nick Clifton <nickc at redhat dot com>]

Hi Joern,

> >  The problem is that the SH2A's "divs" and "divu" instructions should
> >  not be placed into the delay slot of a branch/jump instruction
> >  because they might cause an exception.  This is caught by the
> >  simulator which was how the problem was uncovered.
>
> Does that mean that exceptions thrown by a div[su] instruction in a 
> delay slot need special handling by the exception handler[s], or that 
> the processor doesn't allow these instructions in a delay slot at all?

My understanding is that this processor does not allow these 
instructions in the delay slots at all.  Or rather that the presence of 
such instructions in the delay slot is illegal and their behaviour will 
be undefined.  This was confirmed for us by Allan Tajii of Renesas.

Cheers
  Nick