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/*
* bitops.c --- Bitmap frobbing code. See bitops.h for the inlined
* routines.
*
* Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Library
* General Public License, version 2.
* %End-Header%
*/
#include "config.h"
#include <stdio.h>
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#include "ext2_fs.h"
#include "ext2fs.h"
#ifndef _EXT2_HAVE_ASM_BITOPS_
/*
* For the benefit of those who are trying to port Linux to another
* architecture, here are some C-language equivalents. You should
* recode these in the native assmebly language, if at all possible.
*
* C language equivalents written by Theodore Ts'o, 9/26/92.
* Modified by Pete A. Zaitcev 7/14/95 to be portable to big endian
* systems, as well as non-32 bit systems.
*/
int ext2fs_set_bit(unsigned int nr,void * addr)
{
int mask, retval;
unsigned char *ADDR = (unsigned char *) addr;
ADDR += nr >> 3;
mask = 1 << (nr & 0x07);
retval = mask & *ADDR;
*ADDR |= mask;
return retval;
}
int ext2fs_clear_bit(unsigned int nr, void * addr)
{
int mask, retval;
unsigned char *ADDR = (unsigned char *) addr;
ADDR += nr >> 3;
mask = 1 << (nr & 0x07);
retval = mask & *ADDR;
*ADDR &= ~mask;
return retval;
}
int ext2fs_test_bit(unsigned int nr, const void * addr)
{
int mask;
const unsigned char *ADDR = (const unsigned char *) addr;
ADDR += nr >> 3;
mask = 1 << (nr & 0x07);
return (mask & *ADDR);
}
#endif /* !_EXT2_HAVE_ASM_BITOPS_ */
void ext2fs_warn_bitmap(errcode_t errcode, unsigned long arg,
const char *description)
{
#ifndef OMIT_COM_ERR
if (description)
com_err(0, errcode, "#%lu for %s", arg, description);
else
com_err(0, errcode, "#%lu", arg);
#endif
}
/*
* C-only 64 bit ops.
*/
int ext2fs_set_bit64(__u64 nr, void * addr)
{
int mask, retval;
unsigned char *ADDR = (unsigned char *) addr;
ADDR += nr >> 3;
mask = 1 << (nr & 0x07);
retval = mask & *ADDR;
*ADDR |= mask;
return retval;
}
int ext2fs_clear_bit64(__u64 nr, void * addr)
{
int mask, retval;
unsigned char *ADDR = (unsigned char *) addr;
ADDR += nr >> 3;
mask = 1 << (nr & 0x07);
retval = mask & *ADDR;
*ADDR &= ~mask;
return retval;
}
int ext2fs_test_bit64(__u64 nr, const void * addr)
{
int mask;
const unsigned char *ADDR = (const unsigned char *) addr;
ADDR += nr >> 3;
mask = 1 << (nr & 0x07);
return (mask & *ADDR);
}
static unsigned int popcount8(unsigned int w)
{
unsigned int res = w - ((w >> 1) & 0x55);
res = (res & 0x33) + ((res >> 2) & 0x33);
return (res + (res >> 4)) & 0x0F;
}
static unsigned int popcount32(unsigned int w)
{
unsigned int res = w - ((w >> 1) & 0x55555555);
res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
res = (res + (res >> 4)) & 0x0F0F0F0F;
res = res + (res >> 8);
return (res + (res >> 16)) & 0x000000FF;
}
unsigned int ext2fs_bitcount(const void *addr, unsigned int nbytes)
{
const unsigned char *cp = addr;
const __u32 *p;
unsigned int res = 0;
while (((((uintptr_t) cp) & 3) != 0) && (nbytes > 0)) {
res += popcount8(*cp++);
nbytes--;
}
p = (const __u32 *) cp;
while (nbytes > 4) {
res += popcount32(*p++);
nbytes -= 4;
}
cp = (const unsigned char *) p;
while (nbytes > 0) {
res += popcount8(*cp++);
nbytes--;
}
return res;
}
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