File: [Development] / xfs-linux-nodel / xfs_bit.c (download)
Revision 1.7, Sun Jan 30 09:59:06 2000 UTC (17 years, 8 months ago) by kenmcd
Branch: MAIN
Changes since 1.6: +11 -16
lines
Encumbrance review done.
Add copyright and license words consistent with GPL.
Refer to http://fsg.melbourne.sgi.com/reviews/ for details.
There is a slight change in the license terms and conditions words
to go with the copyrights, so most of the files are not getting
new GPL's, just updated versions ... but there are 20-30 more files
here as well.
|
/*
* Copyright (C) 1999 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; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will 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., 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
*/
#ident "$Revision: 1.5 $"
/*
* XFS bit manipulation routines, used in non-realtime code.
*/
#include <sys/types.h>
#include "xfs_bit.h"
/*
* Index of low bit number in byte, -1 for none set, 0..7 otherwise.
*/
const char xfs_lowbit[256] = {
-1, 0, 1, 0, 2, 0, 1, 0, /* 00 .. 07 */
3, 0, 1, 0, 2, 0, 1, 0, /* 08 .. 0f */
4, 0, 1, 0, 2, 0, 1, 0, /* 10 .. 17 */
3, 0, 1, 0, 2, 0, 1, 0, /* 18 .. 1f */
5, 0, 1, 0, 2, 0, 1, 0, /* 20 .. 27 */
3, 0, 1, 0, 2, 0, 1, 0, /* 28 .. 2f */
4, 0, 1, 0, 2, 0, 1, 0, /* 30 .. 37 */
3, 0, 1, 0, 2, 0, 1, 0, /* 38 .. 3f */
6, 0, 1, 0, 2, 0, 1, 0, /* 40 .. 47 */
3, 0, 1, 0, 2, 0, 1, 0, /* 48 .. 4f */
4, 0, 1, 0, 2, 0, 1, 0, /* 50 .. 57 */
3, 0, 1, 0, 2, 0, 1, 0, /* 58 .. 5f */
5, 0, 1, 0, 2, 0, 1, 0, /* 60 .. 67 */
3, 0, 1, 0, 2, 0, 1, 0, /* 68 .. 6f */
4, 0, 1, 0, 2, 0, 1, 0, /* 70 .. 77 */
3, 0, 1, 0, 2, 0, 1, 0, /* 78 .. 7f */
7, 0, 1, 0, 2, 0, 1, 0, /* 80 .. 87 */
3, 0, 1, 0, 2, 0, 1, 0, /* 88 .. 8f */
4, 0, 1, 0, 2, 0, 1, 0, /* 90 .. 97 */
3, 0, 1, 0, 2, 0, 1, 0, /* 98 .. 9f */
5, 0, 1, 0, 2, 0, 1, 0, /* a0 .. a7 */
3, 0, 1, 0, 2, 0, 1, 0, /* a8 .. af */
4, 0, 1, 0, 2, 0, 1, 0, /* b0 .. b7 */
3, 0, 1, 0, 2, 0, 1, 0, /* b8 .. bf */
6, 0, 1, 0, 2, 0, 1, 0, /* c0 .. c7 */
3, 0, 1, 0, 2, 0, 1, 0, /* c8 .. cf */
4, 0, 1, 0, 2, 0, 1, 0, /* d0 .. d7 */
3, 0, 1, 0, 2, 0, 1, 0, /* d8 .. df */
5, 0, 1, 0, 2, 0, 1, 0, /* e0 .. e7 */
3, 0, 1, 0, 2, 0, 1, 0, /* e8 .. ef */
4, 0, 1, 0, 2, 0, 1, 0, /* f0 .. f7 */
3, 0, 1, 0, 2, 0, 1, 0, /* f8 .. ff */
};
/*
* Index of high bit number in byte, -1 for none set, 0..7 otherwise.
*/
const char xfs_highbit[256] = {
-1, 0, 1, 1, 2, 2, 2, 2, /* 00 .. 07 */
3, 3, 3, 3, 3, 3, 3, 3, /* 08 .. 0f */
4, 4, 4, 4, 4, 4, 4, 4, /* 10 .. 17 */
4, 4, 4, 4, 4, 4, 4, 4, /* 18 .. 1f */
5, 5, 5, 5, 5, 5, 5, 5, /* 20 .. 27 */
5, 5, 5, 5, 5, 5, 5, 5, /* 28 .. 2f */
5, 5, 5, 5, 5, 5, 5, 5, /* 30 .. 37 */
5, 5, 5, 5, 5, 5, 5, 5, /* 38 .. 3f */
6, 6, 6, 6, 6, 6, 6, 6, /* 40 .. 47 */
6, 6, 6, 6, 6, 6, 6, 6, /* 48 .. 4f */
6, 6, 6, 6, 6, 6, 6, 6, /* 50 .. 57 */
6, 6, 6, 6, 6, 6, 6, 6, /* 58 .. 5f */
6, 6, 6, 6, 6, 6, 6, 6, /* 60 .. 67 */
6, 6, 6, 6, 6, 6, 6, 6, /* 68 .. 6f */
6, 6, 6, 6, 6, 6, 6, 6, /* 70 .. 77 */
6, 6, 6, 6, 6, 6, 6, 6, /* 78 .. 7f */
7, 7, 7, 7, 7, 7, 7, 7, /* 80 .. 87 */
7, 7, 7, 7, 7, 7, 7, 7, /* 88 .. 8f */
7, 7, 7, 7, 7, 7, 7, 7, /* 90 .. 97 */
7, 7, 7, 7, 7, 7, 7, 7, /* 98 .. 9f */
7, 7, 7, 7, 7, 7, 7, 7, /* a0 .. a7 */
7, 7, 7, 7, 7, 7, 7, 7, /* a8 .. af */
7, 7, 7, 7, 7, 7, 7, 7, /* b0 .. b7 */
7, 7, 7, 7, 7, 7, 7, 7, /* b8 .. bf */
7, 7, 7, 7, 7, 7, 7, 7, /* c0 .. c7 */
7, 7, 7, 7, 7, 7, 7, 7, /* c8 .. cf */
7, 7, 7, 7, 7, 7, 7, 7, /* d0 .. d7 */
7, 7, 7, 7, 7, 7, 7, 7, /* d8 .. df */
7, 7, 7, 7, 7, 7, 7, 7, /* e0 .. e7 */
7, 7, 7, 7, 7, 7, 7, 7, /* e8 .. ef */
7, 7, 7, 7, 7, 7, 7, 7, /* f0 .. f7 */
7, 7, 7, 7, 7, 7, 7, 7, /* f8 .. ff */
};
/*
* Count of bits set in byte, 0..8.
*/
const char xfs_countbit[256] = {
0, 1, 1, 2, 1, 2, 2, 3, /* 00 .. 07 */
1, 2, 2, 3, 2, 3, 3, 4, /* 08 .. 0f */
1, 2, 2, 3, 2, 3, 3, 4, /* 10 .. 17 */
2, 3, 3, 4, 3, 4, 4, 5, /* 18 .. 1f */
1, 2, 2, 3, 2, 3, 3, 4, /* 20 .. 27 */
2, 3, 3, 4, 3, 4, 4, 5, /* 28 .. 2f */
2, 3, 3, 4, 3, 4, 4, 5, /* 30 .. 37 */
3, 4, 4, 5, 4, 5, 5, 6, /* 38 .. 3f */
1, 2, 2, 3, 2, 3, 3, 4, /* 40 .. 47 */
2, 3, 3, 4, 3, 4, 4, 5, /* 48 .. 4f */
2, 3, 3, 4, 3, 4, 4, 5, /* 50 .. 57 */
3, 4, 4, 5, 4, 5, 5, 6, /* 58 .. 5f */
2, 3, 3, 4, 3, 4, 4, 5, /* 60 .. 67 */
3, 4, 4, 5, 4, 5, 5, 6, /* 68 .. 6f */
3, 4, 4, 5, 4, 5, 5, 6, /* 70 .. 77 */
4, 5, 5, 6, 5, 6, 6, 7, /* 78 .. 7f */
1, 2, 2, 3, 2, 3, 3, 4, /* 80 .. 87 */
2, 3, 3, 4, 3, 4, 4, 5, /* 88 .. 8f */
2, 3, 3, 4, 3, 4, 4, 5, /* 90 .. 97 */
3, 4, 4, 5, 4, 5, 5, 6, /* 98 .. 9f */
2, 3, 3, 4, 3, 4, 4, 5, /* a0 .. a7 */
3, 4, 4, 5, 4, 5, 5, 6, /* a8 .. af */
3, 4, 4, 5, 4, 5, 5, 6, /* b0 .. b7 */
4, 5, 5, 6, 5, 6, 6, 7, /* b8 .. bf */
2, 3, 3, 4, 3, 4, 4, 5, /* c0 .. c7 */
3, 4, 4, 5, 4, 5, 5, 6, /* c8 .. cf */
3, 4, 4, 5, 4, 5, 5, 6, /* d0 .. d7 */
4, 5, 5, 6, 5, 6, 6, 7, /* d8 .. df */
3, 4, 4, 5, 4, 5, 5, 6, /* e0 .. e7 */
4, 5, 5, 6, 5, 6, 6, 7, /* e8 .. ef */
4, 5, 5, 6, 5, 6, 6, 7, /* f0 .. f7 */
5, 6, 6, 7, 6, 7, 7, 8, /* f8 .. ff */
};
/*
* xfs_highbit32: get high bit set out of 32-bit argument, -1 if none set.
*/
int
xfs_highbit32(
__uint32_t v)
{
int i;
if (v & 0xffff0000)
if (v & 0xff000000)
i = 24;
else
i = 16;
else if (v & 0x0000ffff)
if (v & 0x0000ff00)
i = 8;
else
i = 0;
else
return -1;
return i + xfs_highbit[(v >> i) & 0xff];
}
/*
* xfs_lowbit64: get low bit set out of 64-bit argument, -1 if none set.
*/
int
xfs_lowbit64(
__uint64_t v)
{
int i;
#if (_MIPS_SIM == _ABIN32 || _MIPS_SIM == _ABI64)
if (v & 0x00000000ffffffff)
if (v & 0x000000000000ffff)
if (v & 0x00000000000000ff)
i = 0;
else
i = 8;
else
if (v & 0x0000000000ff0000)
i = 16;
else
i = 24;
else if (v & 0xffffffff00000000)
if (v & 0x0000ffff00000000)
if (v & 0x000000ff00000000)
i = 32;
else
i = 40;
else
if (v & 0x00ff000000000000)
i = 48;
else
i = 56;
else
return -1;
return i + xfs_lowbit[(v >> i) & 0xff];
#else
__uint32_t vw;
if (vw = v) {
if (vw & 0x0000ffff)
if (vw & 0x000000ff)
i = 0;
else
i = 8;
else
if (vw & 0x00ff0000)
i = 16;
else
i = 24;
return i + xfs_lowbit[(vw >> i) & 0xff];
} else if (vw = v >> 32) {
if (vw & 0x0000ffff)
if (vw & 0x000000ff)
i = 32;
else
i = 40;
else
if (vw & 0x00ff0000)
i = 48;
else
i = 56;
return i + xfs_lowbit[(vw >> (i - 32)) & 0xff];
} else
return -1;
#endif
}
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