BITMAP_BITREMAP(9) Basic Kernel Library Functions BITMAP_BITREMAP(9)NAMEbitmap_bitremap - Apply map defined by a pair of bitmaps to a single
int bitmap_bitremap(int oldbit, const unsigned long * old,
const unsigned long * new, int bits);
bit position to be mapped
defines domain of map
defines range of map
number of bits in each of these bitmaps
Let old and new define a mapping of bit positions, such that whatever
position is held by the n-th set bit in old is mapped to the n-th set
bit in new. In the more general case, allowing for the possibility that
the weight ´w´ of new is less than the weight of old, map the position
of the n-th set bit in old to the position of the m-th set bit in new,
where m == n % w.
The positions of unset bits in old are mapped to themselves (the
Apply the above specified mapping to bit position oldbit, returning the
new bit position.
For example, lets say that old has bits 4 through 7 set, and new has
bits 12 through 15 set. This defines the mapping of bit position 4 to
12, 5 to 13, 6 to 14 and 7 to 15, and of all other bit positions
unchanged. So if say oldbit is 5, then this routine returns 13.
COPYRIGHTKernel Hackers Manual 2.6. November 2013 BITMAP_BITREMAP(9)