[avr-gcc-list] Detecting ++/-- overflow

[Wallace White]

Speaking of overflows... what's an efficient way to detect when an 
increment or decrement results in an over- or underflow?

Here's what I'm doing now:

    signed int counter, overflow;

    // Increment counter
    if (counter == INT_MAX) {
        counter = INT_MIN;
        overflow++;
    } else {
        counter++;
    }

But you'd like to do something more like this: (I say this not having 
written assembly in a long time)

    counter++;
    if (bit_is_set(SREG, V)) {
        overflow++;
    }

I don't know what you can count on the status register being preserved, 
though, and I don't really know how multiple byte and signed/unsigned 
types are handled. Looks like the INC instruction sets the overflow (V) 
flag for signed overflow only...

Thanks,
Wallace