Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0 */
       2             : /*
       3             :  * Copyright (c) 2000,2002,2005 Silicon Graphics, Inc.
       4             :  * All Rights Reserved.
       5             :  */
       6             : #ifndef __XFS_BIT_H__
       7             : #define __XFS_BIT_H__
       8             : 
       9             : /*
      10             :  * XFS bit manipulation routines.
      11             :  */
      12             : 
      13             : /*
      14             :  * masks with n high/low bits set, 64-bit values
      15             :  */
      16             : static inline uint64_t xfs_mask64hi(int n)
      17             : {
      18             :         return (uint64_t)-1 << (64 - (n));
      19             : }
      20 23004933740 : static inline uint32_t xfs_mask32lo(int n)
      21             : {
      22 23004933740 :         return ((uint32_t)1 << (n)) - 1;
      23             : }
      24             : static inline uint64_t xfs_mask64lo(int n)
      25             : {
      26             :         return ((uint64_t)1 << (n)) - 1;
      27             : }
      28             : 
      29             : /* Get high bit set out of 32-bit argument, -1 if none set */
      30             : static inline int xfs_highbit32(uint32_t v)
      31             : {
      32   108629700 :         return fls(v) - 1;
      33             : }
      34             : 
      35             : /* Get high bit set out of 64-bit argument, -1 if none set */
      36             : static inline int xfs_highbit64(uint64_t v)
      37             : {
      38   167180880 :         return fls64(v) - 1;
      39             : }
      40             : 
      41             : /* Get low bit set out of 32-bit argument, -1 if none set */
      42             : static inline int xfs_lowbit32(uint32_t v)
      43             : {
      44  1011809671 :         return ffs(v) - 1;
      45             : }
      46             : 
      47             : /* Get low bit set out of 64-bit argument, -1 if none set */
      48    84673407 : static inline int xfs_lowbit64(uint64_t v)
      49             : {
      50    84673407 :         uint32_t        w = (uint32_t)v;
      51    84673407 :         int             n = 0;
      52             : 
      53    84673407 :         if (w) {        /* lower bits */
      54    42087152 :                 n = ffs(w);
      55             :         } else {        /* upper bits */
      56    42586255 :                 w = (uint32_t)(v >> 32);
      57    42586255 :                 if (w) {
      58    42534331 :                         n = ffs(w);
      59    42534331 :                         if (n)
      60    42530081 :                                 n += 32;
      61             :                 }
      62             :         }
      63    84673407 :         return n - 1;
      64             : }
      65             : 
      66             : /* Return whether bitmap is empty (1 == empty) */
      67             : extern int xfs_bitmap_empty(uint *map, uint size);
      68             : 
      69             : /* Count continuous one bits in map starting with start_bit */
      70             : extern int xfs_contig_bits(uint *map, uint size, uint start_bit);
      71             : 
      72             : /* Find next set bit in map */
      73             : extern int xfs_next_bit(uint *map, uint size, uint start_bit);
      74             : 
      75             : #endif  /* __XFS_BIT_H__ */