LXR linux/fs/xfs/libxfs/xfs

   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 */
  16static inline uint64_t xfs_mask64hi(int n)
  17{
  18        return (uint64_t)-1 << (64 - (n));
  19}
  20static inline uint32_t xfs_mask32lo(int n)
  21{
  22        return ((uint32_t)1 << (n)) - 1;
  23}
  24static 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 */
  30static inline int xfs_highbit32(uint32_t v)
  31{
  32        return fls(v) - 1;
  33}
  34
  35/* Get high bit set out of 64-bit argument, -1 if none set */
  36static inline int xfs_highbit64(uint64_t v)
  37{
  38        return fls64(v) - 1;
  39}
  40
  41/* Get low bit set out of 32-bit argument, -1 if none set */
  42static inline int xfs_lowbit32(uint32_t v)
  43{
  44        return ffs(v) - 1;
  45}
  46
  47/* Get low bit set out of 64-bit argument, -1 if none set */
  48static inline int xfs_lowbit64(uint64_t v)
  49{
  50        uint32_t        w = (uint32_t)v;
  51        int             n = 0;
  52
  53        if (w) {        /* lower bits */
  54                n = ffs(w);
  55        } else {        /* upper bits */
  56                w = (uint32_t)(v >> 32);
  57                if (w) {
  58                        n = ffs(w);
  59                        if (n)
  60                                n += 32;
  61                }
  62        }
  63        return n - 1;
  64}
  65
  66/* Return whether bitmap is empty (1 == empty) */
  67extern int xfs_bitmap_empty(uint *map, uint size);
  68
  69/* Count continuous one bits in map starting with start_bit */
  70extern int xfs_contig_bits(uint *map, uint size, uint start_bit);
  71
  72/* Find next set bit in map */
  73extern int xfs_next_bit(uint *map, uint size, uint start_bit);
  74
  75#endif  /* __XFS_BIT_H__ */
  76