xref: /freebsd/sys/fs/msdosfs/bootsect.h (revision 41466b50c1d5bfd1cf6adaae547a579a75d7c04e)
1 /* $FreeBSD$ */
2 /*	$NetBSD: bootsect.h,v 1.9 1997/11/17 15:36:17 ws Exp $	*/
3 
4 /*
5  * Written by Paul Popelka (paulp@uts.amdahl.com)
6  *
7  * You can do anything you want with this software, just don't say you wrote
8  * it, and don't remove this notice.
9  *
10  * This software is provided "as is".
11  *
12  * The author supplies this software to be publicly redistributed on the
13  * understanding that the author is not responsible for the correct
14  * functioning of this software in any circumstances and is not liable for
15  * any damages caused by this software.
16  *
17  * October 1992
18  */
19 
20 /*
21  * Format of a boot sector.  This is the first sector on a DOS floppy disk
22  * or the fist sector of a partition on a hard disk.  But, it is not the
23  * first sector of a partitioned hard disk.
24  */
25 struct bootsector33 {
26 	u_int8_t	bsJump[3];		/* jump inst E9xxxx or EBxx90 */
27 	int8_t		bsOemName[8];		/* OEM name and version */
28 	int8_t		bsBPB[19];		/* BIOS parameter block */
29 	int8_t		bsDriveNumber;		/* drive number (0x80) */
30 	int8_t		bsBootCode[479];	/* pad so struct is 512b */
31 	u_int8_t	bsBootSectSig0;
32 	u_int8_t	bsBootSectSig1;
33 #define	BOOTSIG0	0x55
34 #define	BOOTSIG1	0xaa
35 };
36 
37 struct extboot {
38 	int8_t		exDriveNumber;		/* drive number (0x80) */
39 	int8_t		exReserved1;		/* reserved */
40 	int8_t		exBootSignature;	/* ext. boot signature (0x29) */
41 #define	EXBOOTSIG	0x29
42 	int8_t		exVolumeID[4];		/* volume ID number */
43 	int8_t		exVolumeLabel[11];	/* volume label */
44 	int8_t		exFileSysType[8];	/* fs type (FAT12 or FAT16) */
45 };
46 
47 struct bootsector50 {
48 	u_int8_t	bsJump[3];		/* jump inst E9xxxx or EBxx90 */
49 	int8_t		bsOemName[8];		/* OEM name and version */
50 	int8_t		bsBPB[25];		/* BIOS parameter block */
51 	int8_t		bsExt[26];		/* Bootsector Extension */
52 	int8_t		bsBootCode[448];	/* pad so structure is 512b */
53 	u_int8_t	bsBootSectSig0;
54 	u_int8_t	bsBootSectSig1;
55 #define	BOOTSIG0	0x55
56 #define	BOOTSIG1	0xaa
57 };
58 
59 struct bootsector710 {
60 	u_int8_t	bsJump[3];		/* jump inst E9xxxx or EBxx90 */
61 	int8_t		bsOEMName[8];		/* OEM name and version */
62 	int8_t		bsPBP[53];		/* BIOS parameter block */
63 	int8_t		bsExt[26];		/* Bootsector Extension */
64 	int8_t		bsBootCode[418];	/* pad so structure is 512b */
65 	u_int8_t	bsBootSectSig2;		/* 2 & 3 are only defined for FAT32? */
66 	u_int8_t	bsBootSectSig3;
67 	u_int8_t	bsBootSectSig0;
68 	u_int8_t	bsBootSectSig1;
69 #define	BOOTSIG0	0x55
70 #define	BOOTSIG1	0xaa
71 #define	BOOTSIG2	0
72 #define	BOOTSIG3	0
73 };
74 #ifdef	atari
75 /*
76  * The boot sector on a gemdos fs is a little bit different from the msdos fs
77  * format. Currently there is no need to declare a separate structure, the
78  * bootsector33 struct will do.
79  */
80 #if 0
81 struct bootsec_atari {
82 	u_int8_t	bsBranch[2];		/* branch inst if auto-boot	*/
83 	int8_t		bsFiller[6];		/* anything or nothing		*/
84 	int8_t		bsSerial[3];		/* serial no. for mediachange	*/
85 	int8_t		bsBPB[19];		/* BIOS parameter block		*/
86 	int8_t		bsBootCode[482];	/* pad so struct is 512b	*/
87 };
88 #endif
89 #endif /* atari */
90 
91 union bootsector {
92 	struct bootsector33 bs33;
93 	struct bootsector50 bs50;
94 	struct bootsector710 bs710;
95 };
96 
97 #if 0
98 /*
99  * Shorthand for fields in the bpb.
100  */
101 #define	bsBytesPerSec	bsBPB.bpbBytesPerSec
102 #define	bsSectPerClust	bsBPB.bpbSectPerClust
103 #define	bsResSectors	bsBPB.bpbResSectors
104 #define	bsFATS		bsBPB.bpbFATS
105 #define	bsRootDirEnts	bsBPB.bpbRootDirEnts
106 #define	bsSectors	bsBPB.bpbSectors
107 #define	bsMedia		bsBPB.bpbMedia
108 #define	bsFATsecs	bsBPB.bpbFATsecs
109 #define	bsSectPerTrack	bsBPB.bpbSectPerTrack
110 #define	bsHeads		bsBPB.bpbHeads
111 #define	bsHiddenSecs	bsBPB.bpbHiddenSecs
112 #define	bsHugeSectors	bsBPB.bpbHugeSectors
113 #endif
114