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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/i386/lib/bitops.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 'arch/i386/lib/bitops.c')
-rw-r--r--arch/i386/lib/bitops.c70
1 files changed, 70 insertions, 0 deletions
diff --git a/arch/i386/lib/bitops.c b/arch/i386/lib/bitops.c
new file mode 100644
index 000000000000..97db3853dc82
--- /dev/null
+++ b/arch/i386/lib/bitops.c
@@ -0,0 +1,70 @@
1#include <linux/bitops.h>
2#include <linux/module.h>
3
4/**
5 * find_next_bit - find the first set bit in a memory region
6 * @addr: The address to base the search on
7 * @offset: The bitnumber to start searching at
8 * @size: The maximum size to search
9 */
10int find_next_bit(const unsigned long *addr, int size, int offset)
11{
12 const unsigned long *p = addr + (offset >> 5);
13 int set = 0, bit = offset & 31, res;
14
15 if (bit) {
16 /*
17 * Look for nonzero in the first 32 bits:
18 */
19 __asm__("bsfl %1,%0\n\t"
20 "jne 1f\n\t"
21 "movl $32, %0\n"
22 "1:"
23 : "=r" (set)
24 : "r" (*p >> bit));
25 if (set < (32 - bit))
26 return set + offset;
27 set = 32 - bit;
28 p++;
29 }
30 /*
31 * No set bit yet, search remaining full words for a bit
32 */
33 res = find_first_bit (p, size - 32 * (p - addr));
34 return (offset + set + res);
35}
36EXPORT_SYMBOL(find_next_bit);
37
38/**
39 * find_next_zero_bit - find the first zero bit in a memory region
40 * @addr: The address to base the search on
41 * @offset: The bitnumber to start searching at
42 * @size: The maximum size to search
43 */
44int find_next_zero_bit(const unsigned long *addr, int size, int offset)
45{
46 unsigned long * p = ((unsigned long *) addr) + (offset >> 5);
47 int set = 0, bit = offset & 31, res;
48
49 if (bit) {
50 /*
51 * Look for zero in the first 32 bits.
52 */
53 __asm__("bsfl %1,%0\n\t"
54 "jne 1f\n\t"
55 "movl $32, %0\n"
56 "1:"
57 : "=r" (set)
58 : "r" (~(*p >> bit)));
59 if (set < (32 - bit))
60 return set + offset;
61 set = 32 - bit;
62 p++;
63 }
64 /*
65 * No zero yet, search remaining full bytes for a zero
66 */
67 res = find_first_zero_bit (p, size - 32 * (p - (unsigned long *) addr));
68 return (offset + set + res);
69}
70EXPORT_SYMBOL(find_next_zero_bit);