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_ */
113