root/include/linux/bits.h

INCLUDED FROM

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __LINUX_BITS_H
   3 #define __LINUX_BITS_H
   4 
   5 #include <linux/const.h>
   6 #include <asm/bitsperlong.h>
   7 
   8 #define BIT(nr)                 (UL(1) << (nr))
   9 #define BIT_ULL(nr)             (ULL(1) << (nr))
  10 #define BIT_MASK(nr)            (UL(1) << ((nr) % BITS_PER_LONG))
  11 #define BIT_WORD(nr)            ((nr) / BITS_PER_LONG)
  12 #define BIT_ULL_MASK(nr)        (ULL(1) << ((nr) % BITS_PER_LONG_LONG))
  13 #define BIT_ULL_WORD(nr)        ((nr) / BITS_PER_LONG_LONG)
  14 #define BITS_PER_BYTE           8
  15 
  16 /*
  17  * Create a contiguous bitmask starting at bit position @l and ending at
  18  * position @h. For example
  19  * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
  20  */
  21 #define GENMASK(h, l) \
  22         (((~UL(0)) - (UL(1) << (l)) + 1) & \
  23          (~UL(0) >> (BITS_PER_LONG - 1 - (h))))
  24 
  25 #define GENMASK_ULL(h, l) \
  26         (((~ULL(0)) - (ULL(1) << (l)) + 1) & \
  27          (~ULL(0) >> (BITS_PER_LONG_LONG - 1 - (h))))
  28 
  29 #endif  /* __LINUX_BITS_H */