DuffsDevicePerfTest.as

protected function while_loop1():void {
	var l:int = 500000000,
		i:int = 0;
	
	while (i < l){
		i++;
	}			
}


protected function while_loop2():void {
	var l:int = 500000000,
		i:int = 0,
		n:int = l;
	
	while (n--){
		i++;
	}			
}


protected function while_loop_duffs_device1():void {
	var l:int = 500000000,
		i:int = 0,
		n:int = l % 8;
	
	while (n--) {
		i++;
	}
	
	n = Math.floor(l/8);
	
	while (n--) {
		i++;
		i++;
		i++;
		i++;
		i++;
		i++;
		i++;
		i++
	}
}


protected function while_loop_duffs_device2():void {
	var l:int = 500000000,
		i:int = 0,
		n:int = l % 8;
	
	while (n--) {
		i++;
	}
	
	n = Math.floor(l * 0.125); // multiply may be faster than devide
	
	while (n--) {
		i++;
		i++;
		i++;
		i++;
		i++;
		i++;
		i++;
		i++
	}
}




protected function while_loop_duffs_device3():void {
	var l:int = 500000000,
		i:int = 0,
		n:int = l % 8;
	
	while (n--) {
		i++;
	}
	
	n = (l/8) ^ 0; // bitwise operator instead of Math.floor()
	
	while (n--) {
		i++;
		i++;
		i++;
		i++;
		i++;
		i++;
		i++;
		i++
	}
}


protected function while_loop_duffs_device4():void {
	var l:int = 500000000,
		i:int = 0,
		n:int = l % 8;
	
	while (n--) {
		i++;
	}
	
	n = (l * 0.125) ^ 0; // bitwise and multiply
	
	while (n--) {
		i++;
		i++;
		i++;
		i++;
		i++;
		i++;
		i++;
		i++
	}
}

Perf Test

Running tests on MAC 10,1,103,19 RELEASE with loopsMultiple=1...
[TestSuite name='DuffsDevicePerfTest' tareTime=0 time=-1]
	[MethodTest name='while_loop1' time=1259.5 min=1159 max=1351 deviation=0.152 memory=0]
	[MethodTest name='while_loop2' time=985.0 min=843 max=1108 deviation=0.269 memory=0]
	[MethodTest name='while_loop_duffs_device1' time=113.5 min=89 max=138 deviation=0.432 memory=0]
	[MethodTest name='while_loop_duffs_device2' time=114.0 min=89 max=138 deviation=0.430 memory=0]
	[MethodTest name='while_loop_duffs_device3' time=122.0 min=105 max=139 deviation=0.279 memory=0]
	[MethodTest name='while_loop_duffs_device4' time=124.2 min=108 max=141 deviation=0.266 memory=0]