NAME
       GetBPen -- Get the B Pen value for a  RastPort (V39).


   SYNOPSIS
       pen = GetBPen  ( rp )
	d0	   	 a0

	 ULONG GetBPen(struct  RastPort *)

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

   INPUTS
       rp  =  a pointer to a valid  RastPort structure.

   BUGS

   NOTES

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