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author | Ingo Molnar <mingo@elte.hu> | 2009-01-12 11:32:03 +0100 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-01-12 11:32:03 +0100 |
commit | e3ee1e123183ca9847e74b7b8e2694c9e3b817a6 (patch) | |
tree | 652a84674ed05eaa46a813de2223af0bd0168a5a /lib/find_last_bit.c | |
parent | 5762ba1873b0bb9faa631aaa02f533c2b9837f82 (diff) | |
parent | c59765042f53a79a7a65585042ff463b69cb248c (diff) | |
download | kernel-crypto-e3ee1e123183ca9847e74b7b8e2694c9e3b817a6.tar.gz kernel-crypto-e3ee1e123183ca9847e74b7b8e2694c9e3b817a6.tar.xz kernel-crypto-e3ee1e123183ca9847e74b7b8e2694c9e3b817a6.zip |
Merge commit 'v2.6.29-rc1' into timers/hrtimers
Conflicts:
kernel/time/tick-common.c
Diffstat (limited to 'lib/find_last_bit.c')
-rw-r--r-- | lib/find_last_bit.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/lib/find_last_bit.c b/lib/find_last_bit.c new file mode 100644 index 00000000000..5d202e36bdd --- /dev/null +++ b/lib/find_last_bit.c @@ -0,0 +1,45 @@ +/* find_last_bit.c: fallback find next bit implementation + * + * Copyright (C) 2008 IBM Corporation + * Written by Rusty Russell <rusty@rustcorp.com.au> + * (Inspired by David Howell's find_next_bit implementation) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/bitops.h> +#include <linux/module.h> +#include <asm/types.h> +#include <asm/byteorder.h> + +unsigned long find_last_bit(const unsigned long *addr, unsigned long size) +{ + unsigned long words; + unsigned long tmp; + + /* Start at final word. */ + words = size / BITS_PER_LONG; + + /* Partial final word? */ + if (size & (BITS_PER_LONG-1)) { + tmp = (addr[words] & (~0UL >> (BITS_PER_LONG + - (size & (BITS_PER_LONG-1))))); + if (tmp) + goto found; + } + + while (words) { + tmp = addr[--words]; + if (tmp) { +found: + return words * BITS_PER_LONG + __fls(tmp); + } + } + + /* Not found */ + return size; +} +EXPORT_SYMBOL(find_last_bit); |