Re: [avr-gcc-list] How to (efficeiently !!!) test a bit withinamulti-byte intege

[Dave Hansen]

From: Vincent Trouilliez <address@hidden>

[...]

> About the -Os flag, I noticed this morning that it managed MASSIVE code
> size reduction ! SO far I had been using just -O (I guess that means no
> particular optimisation ?), and the program is about 13KB in size. With
> -Os, it's only 10KB !!!  Sadly, for some reason, when compiled with this
> flag, my program misbehaves badly (I get massive corruption of the LCD
> display) !! Too bad... :o(

I believe it was Gerry Weinburg who once wrote that "optimization is easy -- 
if you don't have to get the right answer."

I suspect, though, that some of your code might be relying on behavior 
that's not guaranteed (e.g., the value of an uninitialized variable) rather 
than a bug in the optimizer.

Regards,

  -=Dave