public static Action call(CPU cpu, FlagCondition o1, Immediate<ushort> o2) =>
   () => {
     if (o1.Target)
       cpu.Call(o2.Target, 3);
   };
 public static Action rst(CPU cpu, Fixed o) =>
   () => cpu.Call(o.Target, 1);
 public static Action call(CPU cpu, Immediate<ushort> o) =>
   () => cpu.Call(o.Target, 3);