| /* |
| * 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 <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 (((((unsigned long) 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; |
| } |