M68k C++ Exceptions working!

[Eric Valette]

Ian Lance Taylor wrote:
> 
>    Date: Fri, 14 Jan 2000 14:33:30 +0100
>    From: Eric Valette <valette at crf.canon.fr>
> 
>    Sorry to jump in but I may add the following (especially regarding the
>    recent discussion on the interrupt void* argument to hanlder). A single
>    per thread data software register is usually usefull for multi-thread
>    programming.
> 
> On the i386 I think that would be prohibitively expensive.  There are
> so few registers as it is.
> 
> It's true that many RISC architectures could easily support such a
> register.  In fact, some assign such a register in the conventional
> ABI.

This is not what I was thinking : unless it is specified in the ABI, you
must use a "software" register not
a hardware one.

> rtems_task_get_note(RTEMS_SELF, i, &v) is pretty efficient.  It's a
> single function call that has no loops and calls no other functions.
> (On the other hand, I'm not sure it's interrupt safe.)

I think it should be mapped directly in a global variable
like void* currentThreadCtx (especially if one day memory protection
is targetted...)

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