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author | Dmitry Torokhov <dtor_core@ameritech.net> | 2006-04-02 00:08:05 -0500 |
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committer | Dmitry Torokhov <dtor_core@ameritech.net> | 2006-04-02 00:08:05 -0500 |
commit | 95d465fd750897ab32462a6702fbfe1b122cbbc0 (patch) | |
tree | 65c38b2f11c51bb6932e44dd6c92f15b0091abfe /include/asm-generic/bitops/__ffs.h | |
parent | 642fde17dceceb56c7ba2762733ac688666ae657 (diff) | |
parent | 683aa4012f53b2ada0f430487e05d37b0d94e90a (diff) |
Manual merge with Linus.
Conflicts:
arch/powerpc/kernel/setup-common.c
drivers/input/keyboard/hil_kbd.c
drivers/input/mouse/hil_ptr.c
Diffstat (limited to 'include/asm-generic/bitops/__ffs.h')
-rw-r--r-- | include/asm-generic/bitops/__ffs.h | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/include/asm-generic/bitops/__ffs.h b/include/asm-generic/bitops/__ffs.h new file mode 100644 index 00000000000..9a3274aecf8 --- /dev/null +++ b/include/asm-generic/bitops/__ffs.h @@ -0,0 +1,43 @@ +#ifndef _ASM_GENERIC_BITOPS___FFS_H_ +#define _ASM_GENERIC_BITOPS___FFS_H_ + +#include <asm/types.h> + +/** + * __ffs - find first bit in word. + * @word: The word to search + * + * Undefined if no bit exists, so code should check against 0 first. + */ +static inline unsigned long __ffs(unsigned long word) +{ + int num = 0; + +#if BITS_PER_LONG == 64 + if ((word & 0xffffffff) == 0) { + num += 32; + word >>= 32; + } +#endif + if ((word & 0xffff) == 0) { + num += 16; + word >>= 16; + } + if ((word & 0xff) == 0) { + num += 8; + word >>= 8; + } + if ((word & 0xf) == 0) { + num += 4; + word >>= 4; + } + if ((word & 0x3) == 0) { + num += 2; + word >>= 2; + } + if ((word & 0x1) == 0) + num += 1; + return num; +} + +#endif /* _ASM_GENERIC_BITOPS___FFS_H_ */ |