| [34] | 1 | /* from linux/arch/powerpc/lib/bitops.c */ |
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| 2 | |
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| 3 | #include <asm/types.h> |
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| 4 | #include <asm/bitops.h> |
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| 5 | |
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| 6 | #define BITOP_WORD(nr) ((nr) / BITS_PER_LONG) |
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| 7 | |
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| 8 | /** |
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| 9 | * find_next_bit - find the next set bit in a memory region |
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| 10 | * @addr: The address to base the search on |
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| 11 | * @offset: The bitnumber to start searching at |
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| 12 | * @size: The maximum size to search |
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| 13 | */ |
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| 14 | unsigned long find_next_bit(const unsigned long *addr, unsigned long size, |
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| 15 | unsigned long offset) |
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| 16 | { |
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| 17 | const unsigned long *p = addr + BITOP_WORD(offset); |
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| 18 | unsigned long result = offset & ~(BITS_PER_LONG-1); |
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| 19 | unsigned long tmp; |
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| 20 | |
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| 21 | if (offset >= size) |
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| 22 | return size; |
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| 23 | size -= result; |
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| 24 | offset %= BITS_PER_LONG; |
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| 25 | if (offset) { |
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| 26 | tmp = *(p++); |
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| 27 | tmp &= (~0UL << offset); |
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| 28 | if (size < BITS_PER_LONG) |
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| 29 | goto found_first; |
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| 30 | if (tmp) |
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| 31 | goto found_middle; |
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| 32 | size -= BITS_PER_LONG; |
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| 33 | result += BITS_PER_LONG; |
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| 34 | } |
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| 35 | while (size & ~(BITS_PER_LONG-1)) { |
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| 36 | if ((tmp = *(p++))) |
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| 37 | goto found_middle; |
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| 38 | result += BITS_PER_LONG; |
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| 39 | size -= BITS_PER_LONG; |
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| 40 | } |
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| 41 | if (!size) |
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| 42 | return result; |
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| 43 | tmp = *p; |
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| 44 | |
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| 45 | found_first: |
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| 46 | tmp &= (~0UL >> (BITS_PER_LONG - size)); |
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| 47 | if (tmp == 0UL) /* Are any bits set? */ |
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| 48 | return result + size; /* Nope. */ |
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| 49 | found_middle: |
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| 50 | return result + __ffs(tmp); |
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| 51 | } |
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| 52 | |
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| 53 | /* |
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| 54 | * This implementation of find_{first,next}_zero_bit was stolen from |
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| 55 | * Linus' asm-alpha/bitops.h. |
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| 56 | */ |
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| 57 | unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, |
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| 58 | unsigned long offset) |
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| 59 | { |
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| 60 | const unsigned long *p = addr + BITOP_WORD(offset); |
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| 61 | unsigned long result = offset & ~(BITS_PER_LONG-1); |
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| 62 | unsigned long tmp; |
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| 63 | |
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| 64 | if (offset >= size) |
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| 65 | return size; |
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| 66 | size -= result; |
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| 67 | offset %= BITS_PER_LONG; |
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| 68 | if (offset) { |
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| 69 | tmp = *(p++); |
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| 70 | tmp |= ~0UL >> (BITS_PER_LONG - offset); |
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| 71 | if (size < BITS_PER_LONG) |
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| 72 | goto found_first; |
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| 73 | if (~tmp) |
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| 74 | goto found_middle; |
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| 75 | size -= BITS_PER_LONG; |
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| 76 | result += BITS_PER_LONG; |
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| 77 | } |
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| 78 | while (size & ~(BITS_PER_LONG-1)) { |
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| 79 | if (~(tmp = *(p++))) |
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| 80 | goto found_middle; |
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| 81 | result += BITS_PER_LONG; |
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| 82 | size -= BITS_PER_LONG; |
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| 83 | } |
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| 84 | if (!size) |
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| 85 | return result; |
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| 86 | tmp = *p; |
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| 87 | |
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| 88 | found_first: |
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| 89 | tmp |= ~0UL << size; |
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| 90 | if (tmp == ~0UL) /* Are any bits zero? */ |
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| 91 | return result + size; /* Nope. */ |
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| 92 | found_middle: |
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| 93 | return result + ffz(tmp); |
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| 94 | } |
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