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#1 Nov. 4, 2005 14:53:18

Dave H.
Registered: 2009-11-02
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[avr-gcc-list] How to (efficeiently !!!) test a bit withinamulti-byte intege

From: Vincent Trouilliez <>

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 behaviorthat's not guaranteed (e.g., the value of an uninitialized variable) ratherthan a bug in the optimizer.Regards,


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