1 /* $NetBSD: floppy_2d.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_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