'bx lr' vs 'mov pc,lr'

[Uwe Kleine-König]

On Mon, Sep 14, 2009 at 04:47:35AM +0300, Felipe Contreras wrote:
> On Mon, Sep 14, 2009 at 3:20 AM, Jamie Lokier <jamie at shareable.org> wrote:
> > Felipe Contreras wrote:
> >> > Why do you want bx?  bx isn't available on older CPUs.
> >>
> >> Isn't it faster? I don't know if it would make sense to try it on
> >> newer CPUs.
> >
> > That's interesting.  Do you know if it's faster?
> 
> Nope, I'm assuming because of this:
> http://newsgroups.derkeiler.com/Archive/Comp/comp.sys.arm/2006-04/msg00031.html

For ARM9EJ-S the docs can be found at

	http://infocenter.arm.com/help/topic/com.arm.doc.ddi0222b/I1028171.html

.  bx takes 3 cycles, mov (with dest=pc) takes 4 cycles.

Best regards
Uwe

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