--globals
px,py=64,64

--check if button was pressed previously
function btn_prev(i)
  return (btn(i) and 2^i==band(2^i,btn_))
end

function _update()
  --check if player is still moving in the same direction as last frame
  if not btn(direction) then
    direction=-1
  end

  --check if there is a new button pressed
  for i=0,3 do
    if btn(i) and (not btn_prev(i) or direction==-1) then
      direction=i
    end
  end

  --move player
  if btnp(direction) then
    if direction<=1 then
      px+=(direction-0.5)*16
    else
      py+=(direction-2.5)*16
    end
  end

  --store current buttons
  btn_ = btn()
end

function _draw()
    cls()
    print("direction "..direction)
    print("x "..px..", y "..py)
    pset(px,py)
end