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floppy_2d.c revision 1.2 
      1 /*	$NetBSD: floppy_2d.c,v 1.2 2007/02/21 22:59:42 thorpej 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  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/types.h>
     40 #include "common.h"
     41 
     42 bool
     43 blk_to_2d_position(uint32_t logical_block_number, uint32_t *position,
     44     int *count)
     45 {
     46 	int i, sector, side, cylinder;
     47 
     48 	/*
     49 	 * 2D: MFM format (cylinder 0 side 0 is FM format)
     50 	 *     77 cylinders/disk
     51 	 *	2 sides/disk
     52 	 *     26 sectors/track
     53 	 *    256 bytes/sector (cylinder 0 side 0 is 128 bytes/sector)
     54 	 *
     55 	 *    0-1988 : MFM
     56 	 * 1989-1995 : FM
     57 	 */
     58 	if (logical_block_number > 1988)
     59 		return FALSE;	/* don't support FM track */
     60 
     61 	i = logical_block_number * 2 + 26;
     62 	cylinder = i / (26 * 2);
     63 	side = i - (cylinder * 26 * 2) > 25;
     64 	sector = i - (side + cylinder * 2) * 26 + 1;
     65 	if (position)
     66 		*position = (cylinder << 16) | (side << 8) | sector;
     67 	if (count)
     68 		*count = 2;
     69 
     70 	return TRUE;
     71 }
     72 
     73