Rockbox.org home
release
dev builds
extras
themes manual
wiki
device status forums
mailing lists
IRC bugs
patches
dev guide



Rockbox mail archive

Subject: Re: busy loop

Re: busy loop

From: Edgar Toernig <froese_at_gmx.de>
Date: Tue, 15 Jun 2010 19:36:45 +0200

pouly amaury wrote:
>
> for (x = (unsigned)(FREQ>>22); x; x--)
> asm volatile("":::"memory");
>
> Clobbering memory is likely to prevent gcc from optimizing the loop away.

But it will break with loop-unrolling (i.e. -O3). x times nothing
is nothing ;-) You *have* to use a nop-instruction.

And the cast is bogus - only silences the compiler without fixing
the problem.

Ciao, ET.
Received on 2010-06-15


Page was last modified "Jan 10 2012" The Rockbox Crew
aaa