Define an array of tile to be used by all the tile
     and map functions. 'tile_data' is the address of
     the tile graphics data in memory, 'nb_tile' is
     the number of tile (max. 255), and 'pal_ref' is
     the address of a palette-index array to use
     for tiles; each tile has its own palette index
     attached to it (note that palette indexes must be
     shifted to the left by four bits, ie. 0x40 for
     palette index 4).

     The new 1-parameter form is used together with #inctile_ex()
     or #incchr_ex() directives, where all other relevant data is
     already conveyed in the #incxxx_ex() directive.  Also, this
     form automatically recognizes whether it is being used with
     8x8 (incchr_ex) or 16x16 (inctile_ex) tiles.

     Load tile graphics data in video memory, at address
     'vaddr'. You must first have defined a tile array with
     set_tile_data() before using this function.

     Put individual tiles on the screen, either directly
     at video memory location 'vaddr', or at screen coordinates
     'x/y' (in tile unit). 'num' is a tile index in the tile
     array defined by the most recent call to set_tile_data().

     Modifies the map data (sets a map element to a new tile ID), but
     works only when the map is stored in RAM - ie. a Super CDROM game
     which is loaded into RAM, and executes there.  'x' and 'y' are
     specified in the same units as map_get_tile() (ie. pixels, not tiles).

     Return the tile index as defined in the tile array used in the most
     recent call to set_tile_data(). The 'x/y' argument is in pixel
     units, unlike the put_tile functions and thus this function is ideal
     for colision routines.

     Return the tile index as defined in the tile array used in the most
     recent call to set_tile_data(). The 'x/y' argument is in pixel
     units, unlike the put_tile functions and thus this function is ideal
     for colision routines.

     Define a tile-index map to be used by load_map().
     'map' is the address of a map of width 'w' (max. 255)
     and of height 'h' (max. 255).

     Load a part of a map on the screen. 'sx' and 'sy' are
     screen coordinates (in tile unit; 16 pixels), 'mx' and 'my'
     are position in the map, and 'w' and 'h' are respectively
     the number of tile-index to load horizontaly and verticaly.
     This function doesn't do any screen clipping, so you must
     not pass incorrect or too big screen coordinates to it,
     that would corrupt the video memory.

     Define screen window 'num'. Up to four window can be defined.
     'top' and 'bottom' are the screen top and bottom limits
     of the window (limits are included in the window area).
     'disp' controls the type of the window, if bit 7 is set
     background graphics will be displayed in this window,
     and if bit 6 is set sprites will also be displayed.
     If none of these bits are set the window will stay blank.
     'x' and 'y' are the top-left coordinates of the area
     in the virtual screen that will be displayed in
     the window.

    Disable scrolling for the screen window 'num'.