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Diffstat (limited to 'lib/libzpool/kernel.c')
| -rw-r--r-- | lib/libzpool/kernel.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/lib/libzpool/kernel.c b/lib/libzpool/kernel.c index 49d17ece3..3d85093e2 100644 --- a/lib/libzpool/kernel.c +++ b/lib/libzpool/kernel.c @@ -1071,6 +1071,50 @@ highbit64(uint64_t i) return (h); } +/* + * Find lowest one bit set. + * Returns bit number + 1 of lowest bit that is set, otherwise returns 0. + * This is basically a reimplementation of ffsll(), which is GNU specific. + */ +int +lowbit64(uint64_t i) +{ + register int h = 64; + if (i == 0) + return (0); + + if (i & 0x00000000ffffffffULL) + h -= 32; + else + i >>= 32; + + if (i & 0x0000ffff) + h -= 16; + else + i >>= 16; + + if (i & 0x00ff) + h -= 8; + else + i >>= 8; + + if (i & 0x0f) + h -= 4; + else + i >>= 4; + + if (i & 0x3) + h -= 2; + else + i >>= 2; + + if (i & 0x1) + h -= 1; + + return (h); +} + + static int random_fd = -1, urandom_fd = -1; static int |