Actionscript 3 implementation of Duff's Device. Seems to work well.

IteratorUtil.as

package {

public class IteratorUtil {
	public static function duffDeviceOptimized(ar:Array, process:Function):void {
		var x:int = ar.length;
		if (x > 0) {
			var t:int = 0;
			var n:int = x % 8;
			while (n--) {
				process(ar[t++]);
			}
			n = Math.floor((x + 7) / 8);
			while (n--) {
				process(ar[t++]);
				process(ar[t++]);
				process(ar[t++]);
				process(ar[t++]);
				process(ar[t++]);
				process(ar[t++]);
				process(ar[t++]);
				process(ar[t++]);
			}
		}
	}
	
	public static function duffDeviceSwitch(ar:Array, process:Function):void {
        var x:int = ar.length;
        if (x > 0) {
            var t:int = 0;
            var n:int = Math.floor((x + 7) / 8);
            var startAt:int = x % 8
            do {
                switch (startAt) {
                    case 0:
                        process(ar[t++]);
                    case 7:
                        process(ar[t++]);
                    case 6:
                        process(ar[t++]);
                    case 5:
                        process(ar[t++]);
                    case 4:
                        process(ar[t++]);
                    case 3:
                        process(ar[t++]);
                    case 2:
                        process(ar[t++]);
                    case 1:
                        process(ar[t++]);
                }
                startAt = 0;
            }
            while (--n > 0);
        }
	}
}
}