79071eb0b2
This keeps xfs_lowbit64 as it was since there aren't good generic helpers there ... Patch inspired by Andi Kleen. SGI-PV: 981498 SGI-Modid: xfs-linux-melb:xfs-kern:31472a Signed-off-by: David Chinner <david@fromorbit.com> Signed-off-by: Eric Sandeen <sandeen@sandeen.net> Signed-off-by: Donald Douwsma <donaldd@sgi.com> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
93 lines
2.4 KiB
C
93 lines
2.4 KiB
C
/*
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* Copyright (c) 2000,2002,2005 Silicon Graphics, Inc.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef __XFS_BIT_H__
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#define __XFS_BIT_H__
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/*
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* XFS bit manipulation routines.
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*/
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/*
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* masks with n high/low bits set, 32-bit values & 64-bit values
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*/
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#define XFS_MASK32HI(n) xfs_mask32hi(n)
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static inline __uint32_t xfs_mask32hi(int n)
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{
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return (__uint32_t)-1 << (32 - (n));
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}
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#define XFS_MASK64HI(n) xfs_mask64hi(n)
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static inline __uint64_t xfs_mask64hi(int n)
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{
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return (__uint64_t)-1 << (64 - (n));
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}
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#define XFS_MASK32LO(n) xfs_mask32lo(n)
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static inline __uint32_t xfs_mask32lo(int n)
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{
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return ((__uint32_t)1 << (n)) - 1;
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}
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#define XFS_MASK64LO(n) xfs_mask64lo(n)
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static inline __uint64_t xfs_mask64lo(int n)
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{
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return ((__uint64_t)1 << (n)) - 1;
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}
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/* Get high bit set out of 32-bit argument, -1 if none set */
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static inline int xfs_highbit32(__uint32_t v)
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{
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return fls(v) - 1;
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}
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/* Get high bit set out of 64-bit argument, -1 if none set */
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static inline int xfs_highbit64(__uint64_t v)
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{
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return fls64(v) - 1;
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}
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/* Get low bit set out of 32-bit argument, -1 if none set */
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static inline int xfs_lowbit32(__uint32_t v)
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{
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unsigned long t = v;
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return (v) ? find_first_bit(&t, 32) : -1;
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}
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/* Get low bit set out of 64-bit argument, -1 if none set */
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static inline int xfs_lowbit64(__uint64_t v)
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{
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__uint32_t w = (__uint32_t)v;
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int n = 0;
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if (w) { /* lower bits */
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n = ffs(w);
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} else { /* upper bits */
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w = (__uint32_t)(v >> 32);
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if (w && (n = ffs(w)))
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n += 32;
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}
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return n - 1;
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}
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/* Return whether bitmap is empty (1 == empty) */
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extern int xfs_bitmap_empty(uint *map, uint size);
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/* Count continuous one bits in map starting with start_bit */
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extern int xfs_contig_bits(uint *map, uint size, uint start_bit);
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/* Find next set bit in map */
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extern int xfs_next_bit(uint *map, uint size, uint start_bit);
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#endif /* __XFS_BIT_H__ */
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