[U-Boot] [PATCH 4/8] arm: add __ilog2 function

Rob Herring
2011-06-11T21:46:48Z

From: Rob Herring <rob.herring@calxeda.com>

Add __ilog2 function for ARM. Needed for ahci.c

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
---
arch/arm/include/asm/bitops.h | 9 +++++++++
1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/arch/arm/include/asm/bitops.h b/arch/arm/include/asm/bitops.h
index 270f163..0420182 100644
--- a/arch/arm/include/asm/bitops.h
+++ b/arch/arm/include/asm/bitops.h
@@ -106,6 +106,15 @@ static inline int test_bit(int nr, const void * addr)
return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7));
}

+extern __inline__ int __ilog2(unsigned int x)
+{
+ int ret;
+
+ asm("clz\t%0, %1" : "=r" (ret) : "r" (x));
+ ret = 31 - ret;
+ return ret;
+}
+
/*
* ffz = Find First Zero in word. Undefined if no zero exists,
* so code should check against ~0UL first..
--
1.7.4.1