sys/arch/ews4800mips/stand/common/floppy_2d.c

   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
  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