Deff's Device

gistfile1.js

// Duff's Device
var iterations = Math.floor(items.length / 8),
     startAt = items.length % 8,
     i = 0;

do{
     switch(startAt){
          case 0: process(items[i++]);
          case 7: process(items[i++]);
          case 6: process(items[i++]);
          case 5: process(items[i++]);
          case 4: process(items[i++]);
          case 3: process(items[i++]);
          case 2: process(items[i++]);
          case 1: process(items[i++]);
     }
     startAt = 0;
}while(--iterations);

// faster version
var i = items.length % 8;
while(i){
     process(items[i++]);
}

i = Math.floor(items.length / 8);

while(i){
     process(items[i--]);
     process(items[i--]);
     process(items[i--]);
     process(items[i--]);
     process(items[i--]);
     process(items[i--]);
     process(items[i--]);
     process(items[i--]);
}