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1 /* find_last_bit.c: fallback find next bit implementation
3 * Copyright (C) 2008 IBM Corporation
4 * Written by Rusty Russell <rusty@rustcorp.com.au>
5 * (Inspired by David Howell's find_next_bit implementation)
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
13 #include <linux/bitops.h>
14 #include <linux/module.h>
15 #include <asm/types.h>
16 #include <asm/byteorder.h>
18 unsigned long find_last_bit(const unsigned long *addr
, unsigned long size
)
23 /* Start at final word. */
24 words
= size
/ BITS_PER_LONG
;
26 /* Partial final word? */
27 if (size
& (BITS_PER_LONG
-1)) {
28 tmp
= (addr
[words
] & (~0UL >> (BITS_PER_LONG
29 - (size
& (BITS_PER_LONG
-1)))));
38 return words
* BITS_PER_LONG
+ __fls(tmp
);
45 EXPORT_SYMBOL(find_last_bit
);