diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /lib/find_next_bit.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'lib/find_next_bit.c')
-rw-r--r-- | lib/find_next_bit.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/lib/find_next_bit.c b/lib/find_next_bit.c new file mode 100644 index 000000000000..d08302d2a42c --- /dev/null +++ b/lib/find_next_bit.c | |||
@@ -0,0 +1,55 @@ | |||
1 | /* find_next_bit.c: fallback find next bit implementation | ||
2 | * | ||
3 | * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. | ||
4 | * Written by David Howells (dhowells@redhat.com) | ||
5 | * | ||
6 | * This program is free software; you can redistribute it and/or | ||
7 | * modify it under the terms of the GNU General Public License | ||
8 | * as published by the Free Software Foundation; either version | ||
9 | * 2 of the License, or (at your option) any later version. | ||
10 | */ | ||
11 | |||
12 | #include <linux/bitops.h> | ||
13 | |||
14 | int find_next_bit(const unsigned long *addr, int size, int offset) | ||
15 | { | ||
16 | const unsigned long *base; | ||
17 | const int NBITS = sizeof(*addr) * 8; | ||
18 | unsigned long tmp; | ||
19 | |||
20 | base = addr; | ||
21 | if (offset) { | ||
22 | int suboffset; | ||
23 | |||
24 | addr += offset / NBITS; | ||
25 | |||
26 | suboffset = offset % NBITS; | ||
27 | if (suboffset) { | ||
28 | tmp = *addr; | ||
29 | tmp >>= suboffset; | ||
30 | if (tmp) | ||
31 | goto finish; | ||
32 | } | ||
33 | |||
34 | addr++; | ||
35 | } | ||
36 | |||
37 | while ((tmp = *addr) == 0) | ||
38 | addr++; | ||
39 | |||
40 | offset = (addr - base) * NBITS; | ||
41 | |||
42 | finish: | ||
43 | /* count the remaining bits without using __ffs() since that takes a 32-bit arg */ | ||
44 | while (!(tmp & 0xff)) { | ||
45 | offset += 8; | ||
46 | tmp >>= 8; | ||
47 | } | ||
48 | |||
49 | while (!(tmp & 1)) { | ||
50 | offset++; | ||
51 | tmp >>= 1; | ||
52 | } | ||
53 | |||
54 | return offset; | ||
55 | } | ||