BOOLEAN PcDiskGetDriveGeometry	(	UCHAR	DriveNumber,
		PGEOMETRY	Geometry
	)

Definition at line 303 of file pcdisk.c.

Referenced by PcDiskGetCacheableBlockCount(), and PcMachInit().

{
  EXTENDED_GEOMETRY ExtGeometry;
  REGS RegsIn;
  REGS RegsOut;
  ULONG Cylinders;

  TRACE("DiskGetDriveGeometry()\n");

  /* Try to get the extended geometry first */
  ExtGeometry.Size = sizeof(EXTENDED_GEOMETRY);
  if (DiskGetExtendedDriveParameters(DriveNumber, &ExtGeometry, ExtGeometry.Size))
  {
    Geometry->Cylinders = ExtGeometry.Cylinders;
    Geometry->Heads = ExtGeometry.Heads;
    Geometry->Sectors = ExtGeometry.SectorsPerTrack;
    Geometry->BytesPerSector = ExtGeometry.BytesPerSector;

    return TRUE;
  }

  /* BIOS Int 13h, function 08h - Get drive parameters
   * AH = 08h
   * DL = drive (bit 7 set for hard disk)
   * ES:DI = 0000h:0000h to guard against BIOS bugs
   * Return:
   * CF set on error
   * AH = status (07h)
   * CF clear if successful
   * AH = 00h
   * AL = 00h on at least some BIOSes
   * BL = drive type (AT/PS2 floppies only)
   * CH = low eight bits of maximum cylinder number
   * CL = maximum sector number (bits 5-0)
   *      high two bits of maximum cylinder number (bits 7-6)
   * DH = maximum head number
   * DL = number of drives
   * ES:DI -> drive parameter table (floppies only)
   */
  RegsIn.b.ah = 0x08;
  RegsIn.b.dl = DriveNumber;
  RegsIn.w.es = 0x0000;
  RegsIn.w.di = 0x0000;

  /* Get drive parameters */
  Int386(0x13, &RegsIn, &RegsOut);

  if (! INT386_SUCCESS(RegsOut))
    {
      return FALSE;
    }

  Cylinders = (RegsOut.b.cl & 0xC0) << 2;
  Cylinders += RegsOut.b.ch;
  Cylinders++;
  Geometry->Cylinders = Cylinders;
  Geometry->Heads = RegsOut.b.dh + 1;
  Geometry->Sectors = RegsOut.b.cl & 0x3F;
  Geometry->BytesPerSector = 512;            /* Just assume 512 bytes per sector */

  return TRUE;
}

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