Commit | Line | Data |
---|---|---|
746479cd HC |
1 | /* |
2 | * MSB0 numbered special bitops handling. | |
3 | * | |
48002bd5 | 4 | * The bits are numbered: |
746479cd | 5 | * |0..............63|64............127|128...........191|192...........255| |
746479cd HC |
6 | * |
7 | * The reason for this bit numbering is the fact that the hardware sets bits | |
8 | * in a bitmap starting at bit 0 (MSB) and we don't want to scan the bitmap | |
9 | * from the 'wrong end'. | |
10 | */ | |
11 | ||
12 | #include <linux/compiler.h> | |
13 | #include <linux/bitops.h> | |
14 | #include <linux/export.h> | |
15 | ||
7d7c7b24 | 16 | unsigned long find_first_bit_inv(const unsigned long *addr, unsigned long size) |
746479cd HC |
17 | { |
18 | const unsigned long *p = addr; | |
19 | unsigned long result = 0; | |
20 | unsigned long tmp; | |
21 | ||
22 | while (size & ~(BITS_PER_LONG - 1)) { | |
23 | if ((tmp = *(p++))) | |
24 | goto found; | |
25 | result += BITS_PER_LONG; | |
26 | size -= BITS_PER_LONG; | |
27 | } | |
28 | if (!size) | |
29 | return result; | |
30 | tmp = (*p) & (~0UL << (BITS_PER_LONG - size)); | |
31 | if (!tmp) /* Are any bits set? */ | |
32 | return result + size; /* Nope. */ | |
33 | found: | |
34 | return result + (__fls(tmp) ^ (BITS_PER_LONG - 1)); | |
35 | } | |
7d7c7b24 | 36 | EXPORT_SYMBOL(find_first_bit_inv); |
746479cd | 37 | |
7d7c7b24 HC |
38 | unsigned long find_next_bit_inv(const unsigned long *addr, unsigned long size, |
39 | unsigned long offset) | |
746479cd HC |
40 | { |
41 | const unsigned long *p = addr + (offset / BITS_PER_LONG); | |
42 | unsigned long result = offset & ~(BITS_PER_LONG - 1); | |
43 | unsigned long tmp; | |
44 | ||
45 | if (offset >= size) | |
46 | return size; | |
47 | size -= result; | |
48 | offset %= BITS_PER_LONG; | |
49 | if (offset) { | |
50 | tmp = *(p++); | |
51 | tmp &= (~0UL >> offset); | |
52 | if (size < BITS_PER_LONG) | |
53 | goto found_first; | |
54 | if (tmp) | |
55 | goto found_middle; | |
56 | size -= BITS_PER_LONG; | |
57 | result += BITS_PER_LONG; | |
58 | } | |
59 | while (size & ~(BITS_PER_LONG-1)) { | |
60 | if ((tmp = *(p++))) | |
61 | goto found_middle; | |
62 | result += BITS_PER_LONG; | |
63 | size -= BITS_PER_LONG; | |
64 | } | |
65 | if (!size) | |
66 | return result; | |
67 | tmp = *p; | |
68 | found_first: | |
69 | tmp &= (~0UL << (BITS_PER_LONG - size)); | |
70 | if (!tmp) /* Are any bits set? */ | |
71 | return result + size; /* Nope. */ | |
72 | found_middle: | |
73 | return result + (__fls(tmp) ^ (BITS_PER_LONG - 1)); | |
74 | } | |
7d7c7b24 | 75 | EXPORT_SYMBOL(find_next_bit_inv); |