projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
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 | */ | |
| 10 | int 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 | } | |
| 36 | EXPORT_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 | */ | |
| 44 | int 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 | } | |
| 70 | EXPORT_SYMBOL(find_next_zero_bit); |