freebsd-dev/sys/msdosfs/bpb.h

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/* $Id: bpb.h,v 1.2 1995/05/30 08:07:30 rgrimes Exp $ */
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/* $NetBSD: bpb.h,v 1.3 1994/06/29 06:35:29 cgd Exp $ */
/*
* Written by Paul Popelka (paulp@uts.amdahl.com)
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*
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* You can do anything you want with this software, just don't say you wrote
* it, and don't remove this notice.
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*
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* This software is provided "as is".
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*
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* The author supplies this software to be publicly redistributed on the
* understanding that the author is not responsible for the correct
* functioning of this software in any circumstances and is not liable for
* any damages caused by this software.
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*
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* October 1992
*/
/*
* BIOS Parameter Block (BPB) for DOS 3.3
*/
struct bpb33 {
u_short bpbBytesPerSec; /* bytes per sector */
u_char bpbSecPerClust; /* sectors per cluster */
u_short bpbResSectors; /* number of reserved sectors */
u_char bpbFATs; /* number of FATs */
u_short bpbRootDirEnts; /* number of root directory entries */
u_short bpbSectors; /* total number of sectors */
u_char bpbMedia; /* media descriptor */
u_short bpbFATsecs; /* number of sectors per FAT */
u_short bpbSecPerTrack; /* sectors per track */
u_short bpbHeads; /* number of heads */
u_short bpbHiddenSecs; /* number of hidden sectors */
};
/*
* BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3,
* and bpbHugeSectors is not in the 3.3 bpb.
*/
struct bpb50 {
u_short bpbBytesPerSec; /* bytes per sector */
u_char bpbSecPerClust; /* sectors per cluster */
u_short bpbResSectors; /* number of reserved sectors */
u_char bpbFATs; /* number of FATs */
u_short bpbRootDirEnts; /* number of root directory entries */
u_short bpbSectors; /* total number of sectors */
u_char bpbMedia; /* media descriptor */
u_short bpbFATsecs; /* number of sectors per FAT */
u_short bpbSecPerTrack; /* sectors per track */
u_short bpbHeads; /* number of heads */
u_long bpbHiddenSecs; /* number of hidden sectors */
u_long bpbHugeSectors; /* number of sectors if bpbSectors == 0 */
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};
/*
* The following structures represent how the bpb's look on disk. shorts
* and longs are just character arrays of the appropriate length. This is
* because the compiler forces shorts and longs to align on word or
* halfword boundaries.
*
* XXX The little-endian code here assumes that the processor can access
* 16-bit and 32-bit quantities on byte boundaries. If this is not true,
* use the macros for the big-endian case.
*/
#include <machine/endian.h>
#if BYTE_ORDER == LITTLE_ENDIAN /* && can do unaligned accesses */
#define getushort(x) *((u_short *)(x))
#define getulong(x) *((u_long *)(x))
#define putushort(p, v) (*((u_short *)(p)) = (v))
#define putulong(p, v) (*((u_long *)(p)) = (v))
#else
#define getushort(x) (((u_char *)(x))[0] + (((u_char *)(x))[1] << 8))
#define getulong(x) (((u_char *)(x))[0] + (((u_char *)(x))[1] << 8) \
+ (((u_char *)(x))[2] << 16) \
+ (((u_char *)(x))[3] << 24))
#define putushort(p, v) (((u_char *)(p))[0] = (v), \
((u_char *)(p))[1] = (v) >> 8)
#define putulong(p, v) (((u_char *)(p))[0] = (v), \
((u_char *)(p))[1] = (v) >> 8, \
((u_char *)(p))[2] = (v) >> 16,\
((u_char *)(p))[3] = (v) >> 24)
#endif
/*
* BIOS Parameter Block (BPB) for DOS 3.3
*/
struct byte_bpb33 {
char bpbBytesPerSec[2]; /* bytes per sector */
char bpbSecPerClust; /* sectors per cluster */
char bpbResSectors[2]; /* number of reserved sectors */
char bpbFATs; /* number of FATs */
char bpbRootDirEnts[2]; /* number of root directory entries */
char bpbSectors[2]; /* total number of sectors */
char bpbMedia; /* media descriptor */
char bpbFATsecs[2]; /* number of sectors per FAT */
char bpbSecPerTrack[2]; /* sectors per track */
char bpbHeads[2]; /* number of heads */
char bpbHiddenSecs[2]; /* number of hidden sectors */
};
/*
* BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3,
* and bpbHugeSectors is not in the 3.3 bpb.
*/
struct byte_bpb50 {
char bpbBytesPerSec[2]; /* bytes per sector */
char bpbSecPerClust; /* sectors per cluster */
char bpbResSectors[2]; /* number of reserved sectors */
char bpbFATs; /* number of FATs */
char bpbRootDirEnts[2]; /* number of root directory entries */
char bpbSectors[2]; /* total number of sectors */
char bpbMedia; /* media descriptor */
char bpbFATsecs[2]; /* number of sectors per FAT */
char bpbSecPerTrack[2]; /* sectors per track */
char bpbHeads[2]; /* number of heads */
char bpbHiddenSecs[4]; /* number of hidden sectors */
char bpbHugeSectors[4]; /* number of sectors if bpbSectors == 0 */
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};