1/* find_last_bit.c: fallback find next bit implementation
 2 *
 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)
 6 *
 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.
11 */
12
13#include <linux/bitops.h>
14#include <linux/export.h>
15#include <asm/types.h>
16#include <asm/byteorder.h>
17
18#ifndef find_last_bit
19
20unsigned long find_last_bit(const unsigned long *addr, unsigned long size)
21{
22	unsigned long words;
23	unsigned long tmp;
24
25	/* Start at final word. */
26	words = size / BITS_PER_LONG;
27
28	/* Partial final word? */
29	if (size & (BITS_PER_LONG-1)) {
30		tmp = (addr[words] & (~0UL >> (BITS_PER_LONG
31					 - (size & (BITS_PER_LONG-1)))));
32		if (tmp)
33			goto found;
34	}
35
36	while (words) {
37		tmp = addr[--words];
38		if (tmp) {
39found:
40			return words * BITS_PER_LONG + __fls(tmp);
41		}
42	}
43
44	/* Not found */
45	return size;
46}
47EXPORT_SYMBOL(find_last_bit);
48
49#endif