Source to pcfs/bpb.h


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/*
 *  Written by Paul Popelka ([email protected])
 *
 *  You can do anything you want with this software,
 *    just don't say you wrote it,
 *    and don't remove this notice.
 *
 *  This software is provided "as is".
 *
 *  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.
 *
 *  October 1992
 *
 *	bpb.h,v 1.2 1993/05/20 03:34:04 cgd Exp
 */

/*
 *  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 sectrs if bpbSectors == 0	*/
};

/*
 *  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.
 */
#include <machine/endian.h>
#if BYTE_ORDER == LITTLE_ENDIAN
#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

#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 sectrs if bpbSectors == 0	*/
};