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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 | 41 |
1 files changed, 41 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..fbbb43af7dc0 --- /dev/null +++ b/tools/testing/radix-tree/linux/bitops/ffs.h @@ -0,0 +1,41 @@ +#ifndef _ASM_GENERIC_BITOPS_FFS_H_ +#define _ASM_GENERIC_BITOPS_FFS_H_ + +/** + * ffs - find first bit set + * @x: the word to search + * + * This is defined the same way as + * the libc and compiler builtin ffs routines, therefore + * differs in spirit from the above ffz (man ffs). + */ +static inline int ffs(int x) +{ + int r = 1; + + if (!x) + return 0; + if (!(x & 0xffff)) { + x >>= 16; + r += 16; + } + if (!(x & 0xff)) { + x >>= 8; + r += 8; + } + if (!(x & 0xf)) { + x >>= 4; + r += 4; + } + if (!(x & 3)) { + x >>= 2; + r += 2; + } + if (!(x & 1)) { + x >>= 1; + r += 1; + } + return r; +} + +#endif /* _ASM_GENERIC_BITOPS_FFS_H_ */ |