1/* $NetBSD: bootsect.h,v 1.7 2021/08/09 21:38:05 andvar Exp $ */
2
3/*
4 * Written by Paul Popelka (paulp@uts.amdahl.com)
5 *
6 * You can do anything you want with this software, just don't say you wrote
7 * it, and don't remove this notice.
8 *
9 * This software is provided "as is".
10 *
11 * The author supplies this software to be publicly redistributed on the
12 * understanding that the author is not responsible for the correct
13 * functioning of this software in any circumstances and is not liable for
14 * any damages caused by this software.
15 *
16 * October 1992
17 */
18#ifndef _MSDOSFS_BOOTSECT_H_
19#define _MSDOSFS_BOOTSECT_H_
20
21/*
22 * Format of a boot sector. This is the first sector on a DOS floppy disk
23 * or the first sector of a partition on a hard disk. But, it is not the
24 * first sector of a partitioned hard disk.
25 */
26struct bootsector33 {
27 uint8_t bsJump[3]; /* jump inst E9xxxx or EBxx90 */
28 int8_t bsOemName[8]; /* OEM name and version */
29 int8_t bsBPB[19]; /* BIOS parameter block */
30 int8_t bsDriveNumber; /* drive number (0x80) */
31 int8_t bsBootCode[479]; /* pad so struct is 512b */
32 uint8_t bsBootSectSig0;
33 uint8_t bsBootSectSig1;
34#define BOOTSIG0 0x55
35#define BOOTSIG1 0xaa
36};
37
38struct extboot {
39 int8_t exDriveNumber; /* drive number (0x80) */
40 int8_t exReserved1; /* reserved */
41 int8_t exBootSignature; /* ext. boot signature (0x29) */
42#define EXBOOTSIG 0x29
43 int8_t exVolumeID[4]; /* volume ID number */
44 int8_t exVolumeLabel[11]; /* volume label */
45 int8_t exFileSysType[8]; /* fs type (FAT12 or FAT16) */
46};
47
48struct bootsector50 {
49 uint8_t bsJump[3]; /* jump inst E9xxxx or EBxx90 */
50 int8_t bsOemName[8]; /* OEM name and version */
51 int8_t bsBPB[25]; /* BIOS parameter block */
52 int8_t bsExt[26]; /* Bootsector Extension */
53 int8_t bsBootCode[448]; /* pad so structure is 512b */
54 uint8_t bsBootSectSig0;
55 uint8_t bsBootSectSig1;
56#define BOOTSIG0 0x55
57#define BOOTSIG1 0xaa
58};
59
60struct bootsector710 {
61 uint8_t bsJump[3]; /* jump inst E9xxxx or EBxx90 */
62 int8_t bsOEMName[8]; /* OEM name and version */
63 int8_t bsBPB[53]; /* BIOS parameter block */
64 int8_t bsExt[26]; /* Bootsector Extension */
65 int8_t bsBootCode[420]; /* pad so structure is 512b */
66 uint8_t bsBootSectSig0;
67 uint8_t bsBootSectSig1;
68#define BOOTSIG0 0x55
69#define BOOTSIG1 0xaa
70};
71#ifdef atari
72/*
73 * The boot sector on a GEMDOS FS is a little bit different from the MSDOS FS
74 * format. Currently there is no need to declare a separate structure, the
75 * bootsector33 struct will do.
76 */
77#if 0
78struct bootsec_atari {
79 uint8_t bsBranch[2]; /* branch inst if auto-boot */
80 int8_t bsFiller[6]; /* anything or nothing */
81 int8_t bsSerial[3]; /* serial no. for mediachange */
82 int8_t bsBPB[19]; /* BIOS parameter block */
83 int8_t bsBootCode[482]; /* pad so struct is 512b */
84};
85#endif
86#endif /* atari */
87
88union bootsector {
89 struct bootsector33 bs33;
90 struct bootsector50 bs50;
91 struct bootsector710 bs710;
92};
93
94#if 0
95/*
96 * Shorthand for fields in the bpb.
97 */
98#define bsBytesPerSec bsBPB.bpbBytesPerSec
99#define bsSectPerClust bsBPB.bpbSectPerClust
100#define bsResSectors bsBPB.bpbResSectors
101#define bsFATS bsBPB.bpbFATS
102#define bsRootDirEnts bsBPB.bpbRootDirEnts
103#define bsSectors bsBPB.bpbSectors
104#define bsMedia bsBPB.bpbMedia
105#define bsFATsecs bsBPB.bpbFATsecs
106#define bsSectPerTrack bsBPB.bpbSectPerTrack
107#define bsHeads bsBPB.bpbHeads
108#define bsHiddenSecs bsBPB.bpbHiddenSecs
109#define bsHugeSectors bsBPB.bpbHugeSectors
110#endif
111
112#endif /* _MSDOSFS_BOOTSECT_H_ */