Scroll movieclip at 2x the speed as it currently is

Question

Hi!
I have 2 buttons that are currently scrolling a movie clip with this function on(rollover):
function moveMC(end, dir) {
mc.onEnterFrame = function() {
  if (Math.abs(mc._x-end)>1) {
   mc._x += dir*step;
  } else {
   mc._x = end;
How is it possible to get get it to scroll at 2x that speed on(press)  ?
Thanks for the assistance

Answer 1

Ok, I updated the code to just have the function that you gave me.  All of the on(press) functions have 3 parameters but now when you hold down the on(press), the movie clip doesn't stop at the end parameter like it used to?
Do you see what I mean by looking at the code below?
function moveMC(end, dir, step) {
     mc.onEnterFrame = function() {
          if (Math.abs(mc._x-end)>1) {
               mc._x += dir*step;
          } else {
               mc._x = end;
/*function moveMCTwo(end, dir, step) {
     mc.onEnterFrame = function() {
          if (Math.abs(mc._x-end)>1) {
               mc._x += dir*step;
          } else {
               mc._x = end;
left.onRollOver = function() {
     moveMC(-2410,-1, 5);
     /*if(_root.mc._x > -672){
     moveMC(-660,-1);
     }else if(_root.mc._x == -660){
     trace("done")
left.onRollOut = function() {
     delete mc.onEnterFrame;
left.onPress = function() {
     moveMC(-2410,-1,20);
left.onRelease = function() {
     moveMC(-2410,-1, 5);
right.onRollOver = function() {
     moveMC(488.15,1, 5);
right.onRollOut = function() {
     delete mc.onEnterFrame;
right.onPress = function() {
     moveMC(488.15,1,20);
right.onRelease = function() {
     moveMC(488.15,1, 5);