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ARM: S5PV310: Optimize interrupt source searching code 

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 __ffs().
The __ffs() is implemented using clz instruction.

Suggested-by: Junseok Jung <jundols.jung@samsung.com>
Signed-off-by: Changhwan Youn <chaos.youn@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
This commit is contained in:
Changhwan Youn 2010-09-29 20:31:42 +09:00 committed by Kukjin Kim
parent 8d75c9128a
commit 0c0f909689
1 changed files with 1 additions and 5 deletions
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6
arch/arm/mach-s5pv310/irq-combiner.c
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@ -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 = __ffs(status);
cascade_irq = combiner_irq + (chip_data->irq_offset & ~31);
if (unlikely(cascade_irq >= NR_IRQS))