Michal Nazarewicz wrote:
>
Hi :-)
> On Tue, 28 Sep 2010 14:45:59 +0200, Sergei Shtylyov <sshtylyov@xxxxxxxxxx>
> wrote:
>
> > Hello.
> >
> > On 28-09-2010 5:31, Kukjin Kim wrote:
> >
> >> From: Changhwan Youn<chaos.youn@xxxxxxxxxxx>
> >
> >> It is reported by Junseok Jung that using clz instruction is
> >> better instead of using for-loop to find the interrupt source.
> >> This patch modifies interrupt source searching code using __fls().
> >> The __fls() is implemented using clz instruction.
> >
> >> Suggested-by: Junseok Jung<jundols.jung@xxxxxxxxxxx>
> >> Signed-off-by: Changhwan Youn<chaos.youn@xxxxxxxxxxx>
> >> Signed-off-by: Kukjin Kim<kgene.kim@xxxxxxxxxxx>
> >> ---
> >> arch/arm/mach-s5pv310/irq-combiner.c | 6 +-----
> >> 1 files changed, 1 insertions(+), 5 deletions(-)
> >
> >> diff --git a/arch/arm/mach-s5pv310/irq-combiner.c b/arch/arm/mach-s5pv310/irq-
> combiner.c
> >> index 0f70521..39e3647 100644
> >> --- a/arch/arm/mach-s5pv310/irq-combiner.c
> >> +++ b/arch/arm/mach-s5pv310/irq-combiner.c
> >> @@ -66,11 +66,7 @@ static void combiner_handle_cascade_irq(unsigned int
> irq, struct irq_desc *desc)
> >> if (status == 0)
> >> goto out;
> >>
> >> - for (combiner_irq = 0; combiner_irq< 32; combiner_irq++) {
> >> - if (status & 0x1)
> >> - break;
> >> - status>>= 1;
> >> - }
> >> + combiner_irq = __fls(status);
> >
> > But the loop finds the *first* set bit, not the last...
>
> __ffs than?
>
Yes, already re-submitted.
Thanks.
Best regards,
Kgene.
--
Kukjin Kim <kgene.kim@xxxxxxxxxxx>, Senior Engineer,
SW Solution Development Team, Samsung Electronics Co., Ltd.
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