INT 2F U - ??? (MOUSEPWR.COM, others) - ???    
	AX = 530Bh
	BX = subfunction
	    0003h ???
	    0004h ???
	???
Return: ???
Note:	it appears that subfunction 0003h reads or restores the current mouse
	  settings (the MS Mouse driver hooks AX=530Bh), and 0004h might be
	  the converse