NAME   
	SetAPen -- Set the primary pen for a  RastPort.

   SYNOPSIS
	SetAPen( rp, pen )
		 a1  d0

	void SetAPen( struct  RastPort *,  UBYTE );

   FUNCTION
	Set the primary drawing pen for lines, fills, and text.

   INPUTS
	rp - pointer to  RastPort structure.
	pen - (0-255)

   RESULT
	Changes the minterms in the  RastPort to reflect new primary pen.
	Sets line drawer to restart pattern.

   BUGS

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