NAME
       GetAPen -- Get the A Pen value for a  RastPort (V39).


   SYNOPSIS
       pen = GetAPen  ( rp )
	 d0		 a0

	 ULONG GetAPen(struct  RastPort *)

   FUNCTION
	Return the current value of the A pen for the rastport. This function 
	should be used instead of peeking the structure directly, because future
	graphics devices may store it differently, for instance, using more bits.

   INPUTS
       rp  =  a pointer to a valid  RastPort structure.

   BUGS

   NOTES

   SEE ALSO
	 SetAPen()  sc:include/graphics/gfx.h