Re: reenabling interrupts on return from function

[Justin Carlson <justin@cs.cmu.edu>]

On Sat, 2002-06-15 at 14:49, Justin Carlson wrote:
> I'm obviously missing something basic here.
> 
> Looking at stackframe.h, I see this code as a part of RESTORE_SOME
> 
> 
> 		mfc0	t0, CP0_STATUS;                  \
> 		.set	pop;                             \
> 		ori	t0, 0x1f;                        \
> 		xori	t0, 0x1f;                        \
> 		mtc0	t0, CP0_STATUS;                  
> 

OK, this was a stupid question; the answer was staring me in the face
(the restoration of the status register from the stack), and I didn't
see it.

However, I still don't see the point of the above code.  Why do we
explicitly clear bits 4-0 of the status register just before reloading
it from the system stack?  

-Justin