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[ARM] 5339/1: fix __fls() on ARM

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Commit 0c65f459ce intended to fix truncation issues with fls() on
ARMv5+ by renaming it to __fls() and wrapping it into a C function.
However that didn't take into account the fact that __fls() already
already had different semantics in the kernel.

Let's move the __fls() code into fls() function directly, and redefine
__fls() with the appropriate semantics.  While at it, bring a generic
__fls() definition for pre ARMv5 too.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Nicolas Pitre 2008-12-04 03:59:41 +01:00 committed by Russell King
parent 82676d7625
commit 94fc733664
1 changed files with 10 additions and 6 deletions
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16
arch/arm/include/asm/bitops.h
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@ -237,6 +237,7 @@ extern int _find_next_bit_be(const unsigned long *p, int size, int offset);
#if __LINUX_ARM_ARCH__ < 5
#include <asm-generic/bitops/ffz.h>
#include <asm-generic/bitops/__fls.h>
#include <asm-generic/bitops/__ffs.h>
#include <asm-generic/bitops/fls.h>
#include <asm-generic/bitops/ffs.h>
@ -277,16 +278,19 @@ static inline int constant_fls(int x)
* the clz instruction for much better code efficiency.
*/
#define __fls(x) \
( __builtin_constant_p(x) ? constant_fls(x) : \
({ 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);
int ret;
if (__builtin_constant_p(x))
return constant_fls(x);
asm("clz\t%0, %1" : "=r" (ret) : "r" (x) : "cc");
ret = 32 - ret;
return ret;
}
#define __fls(x) (fls(x) - 1)
#define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); })
#define __ffs(x) (ffs(x) - 1)
#define ffz(x) __ffs( ~(x) )