diff options
| author | Rob Herring <rob.herring@calxeda.com> | 2011-06-28 10:39:40 -0500 |
|---|---|---|
| committer | John Rigby <john.rigby@linaro.org> | 2011-06-30 12:23:33 +0100 |
| commit | 5c4b44bc48bd184c0fe0cd10fea5883f172b537f (patch) | |
| tree | d311a247778cbb232d8359b166b0160d389ef143 | |
| parent | 5d0f72e52e83f99cfab203de3e6d62885a35d6e5 (diff) | |
arm: add __ilog2 function
Add __ilog2 function for ARM. Needed for ahci.c
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Albert ARIBAUD <albert.aribaud@free.fr>
| -rw-r--r-- | 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 270f163ee..04201822e 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.. |