void Area_Display( tiled_area_ptr area, unsigned char far *buffer )
  {
  int y_map_offset,
      x_map_offset,
      y_tile_offset,
      x_tile_offset,
      x_buffer_offset,
      y_buffer_offset,
      win_x,
      win_y,
      win_width,
      win_height,
      map_index,
      map_width,
      tile_height,
      tile_width,
      y_tile_offset_multiplied,
      x_threshold;

  unsigned char far * map;

  map = area->map;

  // set the global tile width and transparency for Draw_Tile
  tile_true_width = area->tile_width;
  tile_transparent = area->transparent;

  // alias tile size;
  tile_height = area->tile_height;
  tile_width = area->tile_width;

  // alias window coordinates
  win_x = area->window_x;
  win_y = area->window_y;
  win_width = area->window_width;
  win_height = area->window_height;

  map_width = area->map_width;

  // alias map coordinates of upper left hand tile
  y_map_offset = area->y;
  x_map_offset = area->x;

  // alias offsets into upper lefthand tile
  y_tile_offset = area->y_off;
  x_tile_offset = area->x_off;

  // compute unclipped upper left corner of visible area->tiles
  y_buffer_offset = win_y - y_tile_offset;
  x_buffer_offset = win_x - x_tile_offset;

  x_threshold = win_x + win_width - tile_width;

  // draw the first row, following rows will not need to be top-clipped
  if(y_buffer_offset < win_y)
    {
    // precompute pointer to destination data
    tile_dest_buffer = buffer + ((win_y << 8) + (win_y << 6) + win_x);
    // precompute starting map location
    map_index = y_map_offset * map_width + x_map_offset;
    // precompute height of row
    tile_draw_height = tile_height - y_tile_offset;
    // precompute y offset into tile buffer
    y_tile_offset_multiplied = y_tile_offset * tile_width;


    // draw the left-clipped first tile, following area->tiles will need no left clipping
    if(x_buffer_offset<win_x)
      {
      // compute the width of the clipped tile
      tile_draw_width = tile_width - x_tile_offset;

      // point to source tile data, checking for null tile
      if((tile_source_buffer = area->tiles[map[map_index]]) != NULL)
	{
	tile_source_buffer += x_tile_offset + y_tile_offset_multiplied;
	// draw the tile
	Draw_Tile();
	}

      // move to next column in buffer and in map
      tile_dest_buffer += tile_draw_width;
      x_buffer_offset += tile_width;
      map_index++;
      }

    // compute the width of the clipped tile
    tile_draw_width = tile_width;

    // draw the unclipped area->tiles in the middle of the row
    while(x_buffer_offset<=x_threshold) // do computation outside whiles
      {
      // point to source tile data, checking for null tile
      if((tile_source_buffer = area->tiles[map[map_index]]) != NULL)
	{
	tile_source_buffer += y_tile_offset_multiplied;
	// draw the tile
	Draw_Tile();
	}

      // move to next column in buffer and in map
      tile_dest_buffer += tile_width;
      x_buffer_offset += tile_width;
      map_index++;
      }

    // draw the final right-clipped tile
    if(x_buffer_offset < win_x+win_width)
      {
      // point to source tile data, checking for null tile
      if((tile_source_buffer = area->tiles[map[map_index]]) != NULL)
	{
	// compute width
	tile_draw_width = win_x + win_width - x_buffer_offset;
	// index into source tile
	tile_source_buffer += y_tile_offset_multiplied;
	// draw the tile
	Draw_Tile();
	}
      }

    // move to next row in buffer and in map
    y_buffer_offset += tile_height;
    y_map_offset++;
    } // end draw clipped top row

  ////////////////////////////////////////////////////

  while(y_buffer_offset <= win_y + win_height-tile_height)
    {
    // move x back to left side of screen
    x_buffer_offset = win_x - x_tile_offset;
    // precompute pointer to destination data
    tile_dest_buffer = buffer + (y_buffer_offset << 8) + (y_buffer_offset << 6) + win_x;
    // precompute starting map location
    map_index = y_map_offset * map_width + x_map_offset;
    // precompute height of row
    tile_draw_height = tile_height;

    // draw the left-clipped first tile, following area->tiles will need no left clipping
    if(x_buffer_offset<win_x)
      {
      // compute the width of the clipped tile
      tile_draw_width = tile_width - x_tile_offset;

      // point to source tile data, checking for null tile
      if((tile_source_buffer = area->tiles[map[map_index]]) != NULL)
	{
	tile_source_buffer += x_tile_offset;
	// draw the tile
	Draw_Tile();
	}

      // move to next column in buffer and in map
      tile_dest_buffer += tile_draw_width;
      x_buffer_offset += tile_width;
      map_index++;
      }

    // compute the width of the clipped tile
    tile_draw_width = tile_width;

    // draw the unclipped area->tiles in the middle of the row
    while(x_buffer_offset<=x_threshold) // do computation outside whiles
      {
      // point to source tile data, checking for null tile
      if((tile_source_buffer = area->tiles[map[map_index]]) != NULL)
	// draw the tile
	Draw_Tile();

      // move to next column in buffer and in map
      tile_dest_buffer += tile_width;
      x_buffer_offset += tile_width;
      map_index++;
      }

    // draw the final right-clipped tile
    if(x_buffer_offset < win_x+win_width)
      {
      // compute width of last tile
      tile_draw_width = win_x + win_width - x_buffer_offset;

      // point to source tile data, checking for null tile
      if((tile_source_buffer = area->tiles[map[map_index]]) != NULL)
	// draw the tile
	Draw_Tile();
      }

    // move to next row in buffer and in map
    y_buffer_offset += tile_height;
    y_map_offset++;
    } // end draw middle rows

  //////////////////////////////////////////////////////

  // draw the final row, bottom clipped
  if(y_buffer_offset <win_y + win_height)
    {
    // move x back to left side of screen
    x_buffer_offset = win_x - x_tile_offset;

    // precompute pointer to destination data
    tile_dest_buffer = buffer + (y_buffer_offset << 8) + (y_buffer_offset << 6) + win_x;
    // precompute starting map location
    map_index = y_map_offset * map_width + x_map_offset;
    // precompute height of row
    tile_draw_height = win_y + win_height - y_buffer_offset;

    // draw the left-clipped first tile, following area->tiles will need no left clipping
    if(x_buffer_offset<win_x)
      {
      // compute the width of the clipped tile
      tile_draw_width = tile_width - x_tile_offset;


      // point to source tile data, checking for null tile
      if((tile_source_buffer = area->tiles[map[map_index]]) != NULL)
	{
	tile_source_buffer += x_tile_offset;
	// draw the tile
	Draw_Tile();
	}

      // move to next column in buffer and in map
      tile_dest_buffer += tile_draw_width;
      x_buffer_offset += tile_width;
      map_index++;
      }

    // compute the width of the clipped tile
    tile_draw_width = tile_width;

    // draw the unclipped area->tiles in the middle of the row
    while(x_buffer_offset<=x_threshold) // do computation outside whiles
      {
      // point to source tile data, checking for null tile
      if((tile_source_buffer = area->tiles[map[map_index]]) != NULL)
	// draw the tile
	Draw_Tile();

      // move to next column in buffer and in map
      tile_dest_buffer += tile_width;
      x_buffer_offset += tile_width;
      map_index++;
      }

    // draw the final right-clipped tile
    if(x_buffer_offset < win_x+win_width)
      {
      // compute width of last tile
      tile_draw_width = win_x + win_width - x_buffer_offset;

      // point to source tile data, checking for null tile
      if((tile_source_buffer = area->tiles[map[map_index]]) != NULL)
	/// draw the tile
	Draw_Tile();
      }
    } // end draw bottom row
  } // end Area_Display