When a variable is marked as volatile (SFR are volatile by definition) the
compiler will never optimize by assuming a given value for this variable.
--
Ori Idan
On 3/22/07, Raphael Neider <[EMAIL PROTECTED]> wrote:
Hi,
> TR0 = 0; // reset the timer
> while( TR0 == 0 ); // wait for the flag to be set.
> i++; // get out of the loop and increment
> }
> What is SDCC going to do in this case.
> Will it say that line corr. to "i++" as unreachable code.
> But how does the compiler know that?
>
If TR0 is not marked as `volatile' and does not refer to an SFR, SDCC
will believe that TR0 cannot be modified behind its back and thus assume
the loop to never be left: TR0 is 0 on entry to the loop, not changed
within, thus TR0 stays 0 forever.
Hope that helped,
Raphael
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