1/*	$NetBSD: floppy_2d.c,v 1.4 2008/04/28 20:23:18 martin Exp $	*/
2
3/*-
4 * Copyright (c) 2004 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by UCHIYAMA Yasushi.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <sys/types.h>
33#include "common.h"
34
35bool
36blk_to_2d_position(uint32_t logical_block_number, uint32_t *position,
37    int *count)
38{
39	int i, sector, side, cylinder;
40
41	/*
42	 * 2D: MFM format (cylinder 0 side 0 is FM format)
43	 *     77 cylinders/disk
44	 *	2 sides/disk
45	 *     26 sectors/track
46	 *    256 bytes/sector (cylinder 0 side 0 is 128 bytes/sector)
47	 *
48	 *    0-1988 : MFM
49	 * 1989-1995 : FM
50	 */
51	if (logical_block_number > 1988)
52		return false;	/* don't support FM track */
53
54	i = logical_block_number * 2 + 26;
55	cylinder = i / (26 * 2);
56	side = i - (cylinder * 26 * 2) > 25;
57	sector = i - (side + cylinder * 2) * 26;
58	if (position)
59		*position = (cylinder << 16) | (side << 8) | (sector + 1);
60	if (count)
61		*count = (26 - sector) / 2;
62
63	return true;
64}
65
66