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kernel/linux-imx6_3.14.28/fs/xfs/xfs_bit.h 2.14 KB
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  /*
   * Copyright (c) 2000,2002,2005 Silicon Graphics, Inc.
   * All Rights Reserved.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it would be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write the Free Software Foundation,
   * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   */
  #ifndef __XFS_BIT_H__
  #define	__XFS_BIT_H__
  
  /*
   * XFS bit manipulation routines.
   */
  
  /*
   * masks with n high/low bits set, 64-bit values
   */
  static inline __uint64_t xfs_mask64hi(int n)
  {
  	return (__uint64_t)-1 << (64 - (n));
  }
  static inline __uint32_t xfs_mask32lo(int n)
  {
  	return ((__uint32_t)1 << (n)) - 1;
  }
  static inline __uint64_t xfs_mask64lo(int n)
  {
  	return ((__uint64_t)1 << (n)) - 1;
  }
  
  /* Get high bit set out of 32-bit argument, -1 if none set */
  static inline int xfs_highbit32(__uint32_t v)
  {
  	return fls(v) - 1;
  }
  
  /* Get high bit set out of 64-bit argument, -1 if none set */
  static inline int xfs_highbit64(__uint64_t v)
  {
  	return fls64(v) - 1;
  }
  
  /* Get low bit set out of 32-bit argument, -1 if none set */
  static inline int xfs_lowbit32(__uint32_t v)
  {
  	return ffs(v) - 1;
  }
  
  /* Get low bit set out of 64-bit argument, -1 if none set */
  static inline int xfs_lowbit64(__uint64_t v)
  {
  	__uint32_t	w = (__uint32_t)v;
  	int		n = 0;
  
  	if (w) {	/* lower bits */
  		n = ffs(w);
  	} else {	/* upper bits */
  		w = (__uint32_t)(v >> 32);
  		if (w && (n = ffs(w)))
  		n += 32;
  	}
  	return n - 1;
  }
  
  /* Return whether bitmap is empty (1 == empty) */
  extern int xfs_bitmap_empty(uint *map, uint size);
  
  /* Count continuous one bits in map starting with start_bit */
  extern int xfs_contig_bits(uint *map, uint size, uint start_bit);
  
  /* Find next set bit in map */
  extern int xfs_next_bit(uint *map, uint size, uint start_bit);
  
  #endif	/* __XFS_BIT_H__ */