fs/xfs/xfs_arch.h

/*
 * Copyright (c) 2000-2002 Silicon Graphics, Inc.  All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Further, this software is distributed without any warranty that it is
 * free of the rightful claim of any third person regarding infringement
 * or the like.  Any license provided herein, whether implied or
 * otherwise, applies only to this software file.  Patent licenses, if
 * any, provided herein do not apply to combinations of this program with
 * other software, or any other product whatsoever.
 *
 * 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.
 *
 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
 * Mountain View, CA  94043, or:
 *
 * http://www.sgi.com
 *
 * For further information regarding this notice, see:
 *
 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
 */
#ifndef __XFS_ARCH_H__
#define __XFS_ARCH_H__

#ifndef XFS_BIG_INUMS
# error XFS_BIG_INUMS must be defined true or false
#endif

#ifdef __KERNEL__

#include <asm/byteorder.h>

#ifdef __LITTLE_ENDIAN
# define __BYTE_ORDER	__LITTLE_ENDIAN
#endif
#ifdef __BIG_ENDIAN
# define __BYTE_ORDER	__BIG_ENDIAN
#endif

#endif	/* __KERNEL__ */

/* do we need conversion? */

#define ARCH_NOCONVERT 1
#if __BYTE_ORDER == __LITTLE_ENDIAN
# define ARCH_CONVERT	0
#else
# define ARCH_CONVERT	ARCH_NOCONVERT
#endif

/* generic swapping macros */

#ifndef HAVE_SWABMACROS
#define INT_SWAP16(type,var) ((typeof(type))(__swab16((__u16)(var))))
#define INT_SWAP32(type,var) ((typeof(type))(__swab32((__u32)(var))))
#define INT_SWAP64(type,var) ((typeof(type))(__swab64((__u64)(var))))
#endif

#define INT_SWAP(type, var) \
    ((sizeof(type) == 8) ? INT_SWAP64(type,var) : \
    ((sizeof(type) == 4) ? INT_SWAP32(type,var) : \
    ((sizeof(type) == 2) ? INT_SWAP16(type,var) : \
    (var))))

/*
 * get and set integers from potentially unaligned locations
 */

#define INT_GET_UNALIGNED_16_BE(pointer) \
   ((__u16)((((__u8*)(pointer))[0] << 8) | (((__u8*)(pointer))[1])))
#define INT_SET_UNALIGNED_16_BE(pointer,value) \
    { \
	((__u8*)(pointer))[0] = (((value) >> 8) & 0xff); \
	((__u8*)(pointer))[1] = (((value)     ) & 0xff); \
    }

/* define generic INT_ macros */

#define INT_GET(reference,arch) \
    (((arch) == ARCH_NOCONVERT) \
	? \
	    (reference) \
	: \
	    INT_SWAP((reference),(reference)) \
    )

/* does not return a value */
#define INT_SET(reference,arch,valueref) \
    (__builtin_constant_p(valueref) ? \
	(void)( (reference) = ( ((arch) != ARCH_NOCONVERT) ? (INT_SWAP((reference),(valueref))) : (valueref)) ) : \
	(void)( \
	    ((reference) = (valueref)), \
	    ( ((arch) != ARCH_NOCONVERT) ? (reference) = INT_SWAP((reference),(reference)) : 0 ) \
	) \
    )

/* does not return a value */
#define INT_MOD_EXPR(reference,arch,code) \
    (((arch) == ARCH_NOCONVERT) \
	? \
	    (void)((reference) code) \
	: \
	    (void)( \
		(reference) = INT_GET((reference),arch) , \
		((reference) code), \
		INT_SET(reference, arch, reference) \
	    ) \
    )

/* does not return a value */
#define INT_MOD(reference,arch,delta) \
    (void)( \
	INT_MOD_EXPR(reference,arch,+=(delta)) \
    )

/*
 * INT_COPY - copy a value between two locations with the
 *	      _same architecture_ but _potentially different sizes_
 *
 *	    if the types of the two parameters are equal or they are
 *		in native architecture, a simple copy is done
 *
 *	    otherwise, architecture conversions are done
 *
 */

/* does not return a value */
#define INT_COPY(dst,src,arch) \
    ( \
	((sizeof(dst) == sizeof(src)) || ((arch) == ARCH_NOCONVERT)) \
	    ? \
		(void)((dst) = (src)) \
	    : \
		INT_SET(dst, arch, INT_GET(src, arch)) \
    )

/*
 * INT_XLATE - copy a value in either direction between two locations
 *	       with different architectures
 *
 *		    dir < 0	- copy from memory to buffer (native to arch)
 *		    dir > 0	- copy from buffer to memory (arch to native)
 */

/* does not return a value */
#define INT_XLATE(buf,mem,dir,arch) {\
    ASSERT(dir); \
    if (dir>0) { \
	(mem)=INT_GET(buf, arch); \
    } else { \
	INT_SET(buf, arch, mem); \
    } \
}

/*
 * In directories inode numbers are stored as unaligned arrays of unsigned
 * 8bit integers on disk.
 *
 * For v1 directories or v2 directories that contain inode numbers that
 * do not fit into 32bit the array has eight members, but the first member
 * is always zero:
 *
 *  |unused|48-55|40-47|32-39|24-31|16-23| 8-15| 0- 7|
 *
 * For v2 directories that only contain entries with inode numbers that fit
 * into 32bits a four-member array is used:
 *
 *  |24-31|16-23| 8-15| 0- 7|
 */ 

#define XFS_GET_DIR_INO4(di) \
	(((u32)(di).i[0] << 24) | ((di).i[1] << 16) | ((di).i[2] << 8) | ((di).i[3]))

#define XFS_PUT_DIR_INO4(from, di) \
do { \
	(di).i[0] = (((from) & 0xff000000ULL) >> 24); \
	(di).i[1] = (((from) & 0x00ff0000ULL) >> 16); \
	(di).i[2] = (((from) & 0x0000ff00ULL) >> 8); \
	(di).i[3] = ((from) & 0x000000ffULL); \
} while (0)

#define XFS_DI_HI(di) \
	(((u32)(di).i[1] << 16) | ((di).i[2] << 8) | ((di).i[3]))
#define XFS_DI_LO(di) \
	(((u32)(di).i[4] << 24) | ((di).i[5] << 16) | ((di).i[6] << 8) | ((di).i[7]))

#define XFS_GET_DIR_INO8(di)        \
	(((xfs_ino_t)XFS_DI_LO(di) & 0xffffffffULL) | \
	 ((xfs_ino_t)XFS_DI_HI(di) << 32))

#define XFS_PUT_DIR_INO8(from, di) \
do { \
	(di).i[0] = 0; \
	(di).i[1] = (((from) & 0x00ff000000000000ULL) >> 48); \
	(di).i[2] = (((from) & 0x0000ff0000000000ULL) >> 40); \
	(di).i[3] = (((from) & 0x000000ff00000000ULL) >> 32); \
	(di).i[4] = (((from) & 0x00000000ff000000ULL) >> 24); \
	(di).i[5] = (((from) & 0x0000000000ff0000ULL) >> 16); \
	(di).i[6] = (((from) & 0x000000000000ff00ULL) >> 8); \
	(di).i[7] = ((from) & 0x00000000000000ffULL); \
} while (0)
	
#endif	/* __XFS_ARCH_H__ */