NAME
       GetRGB4 -- Inquire value of entry in  ColorMap.

   SYNOPSIS
       value = GetRGB4( colormap, entry )
          d0              a0       d0

	 ULONG GetRGB4(struct  ColorMap *,  LONG);

   FUNCTION
	Read and format a value from the  ColorMap.

   INPUTS
	colormap - pointer to  ColorMap structure
	entry - index into colormap

   RESULT
	returns -1 if no valid entry
	return  UWORD RGB value 4 bits per gun right justified

   NOTE
	Intuition's  DisplayBeep() changes color 0. Reading Color 0 during a
	 DisplayBeep() will lead to incorrect results.

   BUGS

   SEE ALSO
        SetRGB4()  LoadRGB4()  GetColorMap()  FreeColorMap()  sc:include/graphics/view.h