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author | Rich Felker <dalias@libc.org> | 2016-03-30 00:53:03 +0300 |
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committer | Rich Felker <dalias@libc.org> | 2016-03-30 00:53:03 +0300 |
commit | 16b02d711f4059b8338ef967064195b47cae65ea (patch) | |
tree | 6d3e0b7629210b56f8d6cfa39184c878d8a15367 /tools/testing/radix-tree/linux/bitops/__ffs.h | |
parent | b15d53d009558d14c4f394a6d1fa2039c7f45c43 (diff) | |
parent | f55532a0c0b8bb6148f4e07853b876ef73bc69ca (diff) | |
download | linux-16b02d711f4059b8338ef967064195b47cae65ea.tar.xz |
Merge tag 'v4.6-rc1'
Linux 4.6-rc1
Diffstat (limited to 'tools/testing/radix-tree/linux/bitops/__ffs.h')
-rw-r--r-- | tools/testing/radix-tree/linux/bitops/__ffs.h | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/tools/testing/radix-tree/linux/bitops/__ffs.h b/tools/testing/radix-tree/linux/bitops/__ffs.h new file mode 100644 index 000000000000..9a3274aecf83 --- /dev/null +++ b/tools/testing/radix-tree/linux/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_ */ |