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author | Takashi Iwai <tiwai@suse.de> | 2009-01-15 18:27:20 +0100 |
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committer | Takashi Iwai <tiwai@suse.de> | 2009-01-15 18:27:20 +0100 |
commit | c0106d72b8d71696dbe9dc80e2c77d4ac63f7531 (patch) | |
tree | ca96d2baecb0555e36219ed6968dc8e306e530ca /lib/find_last_bit.c | |
parent | 5852973c129cf7c7e6c229abb7250673fc2a50c9 (diff) | |
parent | eff317d0834ad1ff03f747f6bc2d76b9a9c95160 (diff) | |
download | kernel-crypto-c0106d72b8d71696dbe9dc80e2c77d4ac63f7531.tar.gz kernel-crypto-c0106d72b8d71696dbe9dc80e2c77d4ac63f7531.tar.xz kernel-crypto-c0106d72b8d71696dbe9dc80e2c77d4ac63f7531.zip |
Merge branch 'topic/asoc' into next/asoc
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); |