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() graphics/rastport.h