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      1 /*	$NetBSD: floppy_2hd_ibmpc.c,v 1.5 2009/02/04 15:22:13 tsutsui 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 
     35 bool
     36 blk_to_2hd_position(uint32_t logical_block_number, uint32_t *position,
     37     int *count)
     38 {
     39 	int sector, side, cylinder;
     40 
     41 	/*
     42 	 * 2HD: MFM format
     43 	 *	80 cylinders/disk
     44 	 *	 2 sides/disk
     45 	 *      18 sectors/track
     46 	 *     512 bytes/sector
     47 	 */
     48 	if (logical_block_number >= 2880)
     49 		return false;
     50 
     51 	cylinder = logical_block_number / (18 * 2);
     52 	side = logical_block_number - (cylinder * 18 * 2) > 17;
     53 	sector = logical_block_number - (side + cylinder * 2) * 18;
     54 
     55 	if (position)
     56 		*position = (cylinder << 16) | (side << 8) | (sector + 1);
     57 	if (count)
     58 		*count = 18 - sector;
     59 
     60 	return true;
     61 }
     62