1/*	$NetBSD: floppy_2hc.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_2hc_position(uint32_t logical_block_number, uint32_t *position,
37    int *count)
38{
39	int sector, side, cylinder;
40
41	/*
42	 * 2HC: MFM format
43	 *	80 cylinders/disk
44	 *	 2 sides/disk
45	 *      15 sectors/track
46	 *     512 bytes/sector
47	 */
48	if (logical_block_number >= 2400)
49		return false;
50
51	cylinder = logical_block_number / (15 * 2);
52	side = logical_block_number - (cylinder * 15 * 2) > 14;
53	sector = logical_block_number - (side + cylinder * 2) * 15;
54
55	if (position)
56		*position = (cylinder << 16) | (side << 8) | (sector + 1);
57	if (count)
58		*count = 15 - sector;
59
60	return true;
61}
62