Re: [avr-gcc-list] gcc signal overhead, redundant code, bug (?), far from optimal

[David Kelly]

On Aug 18, 2005, at 1:21 PM, Szikra Istvan wrote:

> Thank You for the fast response, but I'm not sure if I understand  
> you right.
>
> INTERRUPTs can be interrupted (by other interrupts or signals) and  
> SIGNALS
> not.

Yup. And I responded faster than my brain could shift gears and got  
my INTERRUPT and SIGNAL crossed.

> All my questions still remain!

Believe J"org addressed everything in full. That the compiler simply  
can't know that other routines have left __zero_reg__ alone and the  
compiler expects to find zero there.

As for SREG, no telling what another routine was doing with the  
status bits so it too has to be saved and restored before any of its  
contents possibly get modified. CISC CPUs do this for you when  
stacking the IRQ, and on RTI.

--
David Kelly N4HHE, address@hidden
========================================================================
Whom computers would destroy, they must first drive mad.