structure MipsFrame : FRAME = struct

datatype frame = Frame of (access list (* formals *)
			  (* * instructions I don't really understand this?*)
			   * int (* locals allocated so far *)
			   * Temp.label (* name of fun label *)
			   )


datatype access = InFrame of int | InReg of Temp.temp


    

fun newFrame (name, formals: bool list) = 

(* Do we actually have to add the size / number of saved registers to
the inFrame(number)? *)

	(*map the bool list onto the access list, accumulating the count
	of local params along the way *)

	let fun mapBools(escapes::[], depth, regsAllocated) = 
		if (escapes orelse (regsAllocated >= 4)) then
		    ([InFrame(4 * depth)], depth+1)
		else
		    ([Inreg (newlabel depth)], depth+1)
		    
	      | mapBools (escapes::tail, depth, regsAllocated) =
		if (escapes orelse (regsAllocated >= 4)) then
		    (InFrame (4 * depth)::#1(mapBools(tail, depth+1, regsAllocated)),
		     depth+1)
		else
		    (InReg(newlabel depth)::#1(mapBools(tail, depth+1, regsAllocated+1)),
		     depth+1)
		    
	    val (access', depth') = mapBools (formals,0,0)
	in
	    (access'
	     ,blah
	     ,depth'
	     ,Temp.newlabel(name))
	end
(* ----------------------------------------------------------------- *)
fun name (MipsFrame.Frame (_, _, _, n) = n;
(* ----------------------------------------------------------------- *)
fun formals (MipsFrame.Frame (f, _, _, _) = f;
(* ----------------------------------------------------------------- *)
fun allocLocal (frame:frame, escapes:bool) =

    (* how do we decide when to allocate something in a register? for
    now lets just put everything on the frame *)
    if (bool) then
	(