projects / deliverable / linux.git / blame
| 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); |