linux-master/lib/bitmap.c

561  * 	@orig: original untranslated bitmap
566  * n-th bit of @relmap is set, the m-th bit of @orig is set, and
571  * In other words, @orig is mapped onto (surjectively) @dst,
575  * Any set bits in @orig above bit number W, where W is the
577  * In particular, if for all bits m set in @orig, m >= W, then
581  * @orig bitmap over itself so that all its set bits x are in the
583  * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
586  *  Let's say @relmap has bits 30-39 set, and @orig has bits
590  *  When bit 0 is set in @orig, it means turn on the bit in
595  *  When bit 1 is set in @orig (as in the above example), it
604  *  @orig (i.e. bits 3, 5, 7 and 9) were also set.
606  *  When bit 11 is set in @orig, it means turn on the bit in
610  *  11 was set in @orig had no affect on @dst.
626  *	bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
630  *  various @orig's.  I list the zero-based positions of each set bit.
632  *  using bitmap_fold() to fold the @orig bitmap modulo ten
636  *      @orig           tmp            @dst
655  * If either of @orig or @relmap is empty (no set bits), then @dst
658  * If (as explained above) the only set bits in @orig are in positions
664 void bitmap_onto(unsigned long *dst, const unsigned long *orig,
669 	if (dst == orig)	/* following doesn't handle inplace mappings */
677 	 *		n = find_nth_bit(orig, bits, m);
678 	 *		if (test_bit(m, orig))
686 		if (test_bit(m, orig))
695  *	@orig: original larger bitmap
699  * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
703 void bitmap_fold(unsigned long *dst, const unsigned long *orig,
708 	if (dst == orig)	/* following doesn't handle inplace mappings */
712 	for_each_set_bit(oldbit, orig, nbits)