Different Duff's device and normal loop test

/*
* This is a test to check the performance of different Duff's device and normal loop
*/
var myArray = new Array(1000033);
var myArray1 = new Array(1000033);
var myArray2 = new Array(1000033);

// Jeff Greenberg's implementation of Duff's device
function jeffDuff(){
	var iterations = Math.ceil(myArray.length / 8),
	startAt = myArray.length % 8,
	i = 0;
	
	do {
		switch(startAt){
			case 0: myArray[i++] = i;
			case 7: myArray[i++] = i;
			case 6: myArray[i++] = i;
			case 5: myArray[i++] = i;
			case 4: myArray[i++] = i;
			case 3: myArray[i++] = i;
			case 2: myArray[i++] = i;
			case 1: myArray[i++] = i;
		}
		startAt = 0;
	} while (--iterations > 0);
}

// Andrew B. King's implementation of Duff's device
function kingDuff(){
	var iterations = Math.floor(myArray1.length / 8),
	leftover = myArray1.length % 8,
	i = 0;

	if (leftover > 0){
		do {
			myArray1[i++] = i;
		} while (--leftover > 0);
	}
	
	do {
		myArray1[i++] = i;
		myArray1[i++] = i;
		myArray1[i++] = i;
		myArray1[i++] = i;
		myArray1[i++] = i;
		myArray1[i++] = i;
		myArray1[i++] = i;
		myArray1[i++] = i;
	} while (--iterations > 0);
}

// normal loop
function normalLoop(){
	for(var i=0, len=myArray2.length;i<len;i++){
		myArray2[i++] = i;
	}
}

console.time("normalLoop");
normalLoop();
console.timeEnd("normalLoop");

console.time("kingDuff");
kingDuff();
console.timeEnd("kingDuff");

console.time("jeffDuff");
jeffDuff();
console.timeEnd("jeffDuff");

// release memory
myArray = null;
myArray1 = null;
myArray2 = null;