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* Copyright (c) 2000 Silicon Graphics, Inc. All Rights Reserved.
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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* This program is distributed in the hope that it would be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* Further, this software is distributed without any warranty that it is
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* free of the rightful claim of any third person regarding infringement
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* or the like. Any license provided herein, whether implied or
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* otherwise, applies only to this software file. Patent licenses, if
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* any, provided herein do not apply to combinations of this program with
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* other software, or any other product whatsoever.
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write the Free Software Foundation, Inc., 59
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* Temple Place - Suite 330, Boston MA 02111-1307, USA.
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* Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
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* Mountain View, CA 94043, or:
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* For further information regarding this notice, see:
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* http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
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* XFS bit manipulation routines, used in non-realtime code.
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* Index of low bit number in byte, -1 for none set, 0..7 otherwise.
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const char xfs_lowbit[256] = {
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-1, 0, 1, 0, 2, 0, 1, 0, /* 00 .. 07 */
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3, 0, 1, 0, 2, 0, 1, 0, /* 08 .. 0f */
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4, 0, 1, 0, 2, 0, 1, 0, /* 10 .. 17 */
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3, 0, 1, 0, 2, 0, 1, 0, /* 18 .. 1f */
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5, 0, 1, 0, 2, 0, 1, 0, /* 20 .. 27 */
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3, 0, 1, 0, 2, 0, 1, 0, /* 28 .. 2f */
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4, 0, 1, 0, 2, 0, 1, 0, /* 30 .. 37 */
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3, 0, 1, 0, 2, 0, 1, 0, /* 38 .. 3f */
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6, 0, 1, 0, 2, 0, 1, 0, /* 40 .. 47 */
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3, 0, 1, 0, 2, 0, 1, 0, /* 48 .. 4f */
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4, 0, 1, 0, 2, 0, 1, 0, /* 50 .. 57 */
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3, 0, 1, 0, 2, 0, 1, 0, /* 58 .. 5f */
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5, 0, 1, 0, 2, 0, 1, 0, /* 60 .. 67 */
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3, 0, 1, 0, 2, 0, 1, 0, /* 68 .. 6f */
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4, 0, 1, 0, 2, 0, 1, 0, /* 70 .. 77 */
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3, 0, 1, 0, 2, 0, 1, 0, /* 78 .. 7f */
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7, 0, 1, 0, 2, 0, 1, 0, /* 80 .. 87 */
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3, 0, 1, 0, 2, 0, 1, 0, /* 88 .. 8f */
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4, 0, 1, 0, 2, 0, 1, 0, /* 90 .. 97 */
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3, 0, 1, 0, 2, 0, 1, 0, /* 98 .. 9f */
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5, 0, 1, 0, 2, 0, 1, 0, /* a0 .. a7 */
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3, 0, 1, 0, 2, 0, 1, 0, /* a8 .. af */
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4, 0, 1, 0, 2, 0, 1, 0, /* b0 .. b7 */
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3, 0, 1, 0, 2, 0, 1, 0, /* b8 .. bf */
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6, 0, 1, 0, 2, 0, 1, 0, /* c0 .. c7 */
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3, 0, 1, 0, 2, 0, 1, 0, /* c8 .. cf */
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4, 0, 1, 0, 2, 0, 1, 0, /* d0 .. d7 */
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3, 0, 1, 0, 2, 0, 1, 0, /* d8 .. df */
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5, 0, 1, 0, 2, 0, 1, 0, /* e0 .. e7 */
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3, 0, 1, 0, 2, 0, 1, 0, /* e8 .. ef */
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4, 0, 1, 0, 2, 0, 1, 0, /* f0 .. f7 */
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3, 0, 1, 0, 2, 0, 1, 0, /* f8 .. ff */
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* Index of high bit number in byte, -1 for none set, 0..7 otherwise.
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const char xfs_highbit[256] = {
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-1, 0, 1, 1, 2, 2, 2, 2, /* 00 .. 07 */
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3, 3, 3, 3, 3, 3, 3, 3, /* 08 .. 0f */
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4, 4, 4, 4, 4, 4, 4, 4, /* 10 .. 17 */
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4, 4, 4, 4, 4, 4, 4, 4, /* 18 .. 1f */
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5, 5, 5, 5, 5, 5, 5, 5, /* 20 .. 27 */
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5, 5, 5, 5, 5, 5, 5, 5, /* 28 .. 2f */
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5, 5, 5, 5, 5, 5, 5, 5, /* 30 .. 37 */
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5, 5, 5, 5, 5, 5, 5, 5, /* 38 .. 3f */
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6, 6, 6, 6, 6, 6, 6, 6, /* 40 .. 47 */
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6, 6, 6, 6, 6, 6, 6, 6, /* 48 .. 4f */
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6, 6, 6, 6, 6, 6, 6, 6, /* 50 .. 57 */
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6, 6, 6, 6, 6, 6, 6, 6, /* 58 .. 5f */
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6, 6, 6, 6, 6, 6, 6, 6, /* 60 .. 67 */
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6, 6, 6, 6, 6, 6, 6, 6, /* 68 .. 6f */
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6, 6, 6, 6, 6, 6, 6, 6, /* 70 .. 77 */
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6, 6, 6, 6, 6, 6, 6, 6, /* 78 .. 7f */
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7, 7, 7, 7, 7, 7, 7, 7, /* 80 .. 87 */
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7, 7, 7, 7, 7, 7, 7, 7, /* 88 .. 8f */
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7, 7, 7, 7, 7, 7, 7, 7, /* 90 .. 97 */
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7, 7, 7, 7, 7, 7, 7, 7, /* 98 .. 9f */
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7, 7, 7, 7, 7, 7, 7, 7, /* a0 .. a7 */
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7, 7, 7, 7, 7, 7, 7, 7, /* a8 .. af */
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7, 7, 7, 7, 7, 7, 7, 7, /* b0 .. b7 */
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7, 7, 7, 7, 7, 7, 7, 7, /* b8 .. bf */
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7, 7, 7, 7, 7, 7, 7, 7, /* c0 .. c7 */
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7, 7, 7, 7, 7, 7, 7, 7, /* c8 .. cf */
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7, 7, 7, 7, 7, 7, 7, 7, /* d0 .. d7 */
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7, 7, 7, 7, 7, 7, 7, 7, /* d8 .. df */
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7, 7, 7, 7, 7, 7, 7, 7, /* e0 .. e7 */
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7, 7, 7, 7, 7, 7, 7, 7, /* e8 .. ef */
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7, 7, 7, 7, 7, 7, 7, 7, /* f0 .. f7 */
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7, 7, 7, 7, 7, 7, 7, 7, /* f8 .. ff */
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* Count of bits set in byte, 0..8.
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const char xfs_countbit[256] = {
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0, 1, 1, 2, 1, 2, 2, 3, /* 00 .. 07 */
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1, 2, 2, 3, 2, 3, 3, 4, /* 08 .. 0f */
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1, 2, 2, 3, 2, 3, 3, 4, /* 10 .. 17 */
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2, 3, 3, 4, 3, 4, 4, 5, /* 18 .. 1f */
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1, 2, 2, 3, 2, 3, 3, 4, /* 20 .. 27 */
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2, 3, 3, 4, 3, 4, 4, 5, /* 28 .. 2f */
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2, 3, 3, 4, 3, 4, 4, 5, /* 30 .. 37 */
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3, 4, 4, 5, 4, 5, 5, 6, /* 38 .. 3f */
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1, 2, 2, 3, 2, 3, 3, 4, /* 40 .. 47 */
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2, 3, 3, 4, 3, 4, 4, 5, /* 48 .. 4f */
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2, 3, 3, 4, 3, 4, 4, 5, /* 50 .. 57 */
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3, 4, 4, 5, 4, 5, 5, 6, /* 58 .. 5f */
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2, 3, 3, 4, 3, 4, 4, 5, /* 60 .. 67 */
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3, 4, 4, 5, 4, 5, 5, 6, /* 68 .. 6f */
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3, 4, 4, 5, 4, 5, 5, 6, /* 70 .. 77 */
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4, 5, 5, 6, 5, 6, 6, 7, /* 78 .. 7f */
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1, 2, 2, 3, 2, 3, 3, 4, /* 80 .. 87 */
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2, 3, 3, 4, 3, 4, 4, 5, /* 88 .. 8f */
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2, 3, 3, 4, 3, 4, 4, 5, /* 90 .. 97 */
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3, 4, 4, 5, 4, 5, 5, 6, /* 98 .. 9f */
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2, 3, 3, 4, 3, 4, 4, 5, /* a0 .. a7 */
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3, 4, 4, 5, 4, 5, 5, 6, /* a8 .. af */
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3, 4, 4, 5, 4, 5, 5, 6, /* b0 .. b7 */
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4, 5, 5, 6, 5, 6, 6, 7, /* b8 .. bf */
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2, 3, 3, 4, 3, 4, 4, 5, /* c0 .. c7 */
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3, 4, 4, 5, 4, 5, 5, 6, /* c8 .. cf */
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3, 4, 4, 5, 4, 5, 5, 6, /* d0 .. d7 */
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4, 5, 5, 6, 5, 6, 6, 7, /* d8 .. df */
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3, 4, 4, 5, 4, 5, 5, 6, /* e0 .. e7 */
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4, 5, 5, 6, 5, 6, 6, 7, /* e8 .. ef */
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4, 5, 5, 6, 5, 6, 6, 7, /* f0 .. f7 */
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5, 6, 6, 7, 6, 7, 7, 8, /* f8 .. ff */
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* xfs_highbit32: get high bit set out of 32-bit argument, -1 if none set.
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else if (v & 0x0000ffff)
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return i + xfs_highbit[(v >> i) & 0xff];
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* xfs_lowbit64: get low bit set out of 64-bit argument, -1 if none set.
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if (v & 0x00000000ffffffff)
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if (v & 0x000000000000ffff)
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if (v & 0x00000000000000ff)
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if (v & 0x0000000000ff0000)
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else if (v & 0xffffffff00000000)
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if (v & 0x0000ffff00000000)
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if (v & 0x000000ff00000000)
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if (v & 0x00ff000000000000)
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return i + xfs_lowbit[(v >> i) & 0xff];
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return i + xfs_lowbit[(vw >> i) & 0xff];
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} else if ((vw = v >> 32)) {
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return i + xfs_lowbit[(vw >> (i - 32)) & 0xff];
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* xfs_highbit64: get high bit set out of 64-bit argument, -1 if none set.
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if (v & 0xffffffff00000000)
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if (v & 0xffff000000000000)
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if (v & 0xff00000000000000)
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if (v & 0x0000ff0000000000)
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else if (v & 0x00000000ffffffff)
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if (v & 0x00000000ffff0000)
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if (v & 0x00000000ff000000)
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if (v & 0x000000000000ff00)
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return i + xfs_highbit[(v >> i) & 0xff];
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if ((vw = v >> 32)) {
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return i + xfs_highbit[(vw >> (i - 32)) & 0xff];
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} else if ((vw = v)) {
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return i + xfs_highbit[(vw >> i) & 0xff];
added
removed
libxfs/xfs_bit.c
