1BITMAP_REMAP(9)         Basic Kernel Library Functions         BITMAP_REMAP(9)
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NAME

6       bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
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SYNOPSIS

9       void bitmap_remap(unsigned long * dst, const unsigned long * src,
10                         const unsigned long * old, const unsigned long * new,
11                         int bits);
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ARGUMENTS

14       dst
15           remapped result
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17       src
18           subset to be remapped
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20       old
21           defines domain of map
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23       new
24           defines range of map
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26       bits
27           number of bits in each of these bitmaps
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DESCRIPTION

30       Let old and new define a mapping of bit positions, such that whatever
31       position is held by the n-th set bit in old is mapped to the n-th set
32       bit in new. In the more general case, allowing for the possibility that
33       the weight 'w' of new is less than the weight of old, map the position
34       of the n-th set bit in old to the position of the m-th set bit in new,
35       where m == n % w.
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37       If either of the old and new bitmaps are empty, or if src and dst point
38       to the same location, then this routine copies src to dst.
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40       The positions of unset bits in old are mapped to themselves (the
41       identify map).
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43       Apply the above specified mapping to src, placing the result in dst,
44       clearing any bits previously set in dst.
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46       For example, lets say that old has bits 4 through 7 set, and new has
47       bits 12 through 15 set. This defines the mapping of bit position 4 to
48       12, 5 to 13, 6 to 14 and 7 to 15, and of all other bit positions
49       unchanged. So if say src comes into this routine with bits 1, 5 and 7
50       set, then dst should leave with bits 1, 13 and 15 set.
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53Kernel Hackers Manual 3.10         June 2019                   BITMAP_REMAP(9)
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