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[ARM] fix fls() for 64-bit arguments 

arm's fls() is implemented as a macro, causing it to misbehave when passed
64-bit arguments.  Fix.

Cc: Nickolay Vinogradov <nickolay@protei.ru>
Tested-by: Krzysztof Halasa <khc@pm.waw.pl>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Andrew Morton 2008-07-23 15:35:22 -07:00 committed by Russell King
parent 9d9fa83bea
commit 0c65f459ce
1 changed files with 8 additions and 1 deletions
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9
include/asm-arm/bitops.h
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@ -277,9 +277,16 @@ static inline int constant_fls(int x)
* the clz instruction for much better code efficiency. * the clz instruction for much better code efficiency.
*/ */
#define fls(x) \ #define __fls(x) \
( __builtin_constant_p(x) ? constant_fls(x) : \ ( __builtin_constant_p(x) ? constant_fls(x) : \
({ int __r; asm("clz\t%0, %1" : "=r"(__r) : "r"(x) : "cc"); 32-__r; }) ) ({ int __r; asm("clz\t%0, %1" : "=r"(__r) : "r"(x) : "cc"); 32-__r; }) )
/* Implement fls() in C so that 64-bit args are suitably truncated */
static inline int fls(int x)
{
return __fls(x);
}
#define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); }) #define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); })
#define __ffs(x) (ffs(x) - 1) #define __ffs(x) (ffs(x) - 1)
#define ffz(x) __ffs( ~(x) ) #define ffz(x) __ffs( ~(x) )