public static void stepTypes(DataPoint data, Instruction instr, ConstantPool pool) {
    ListStack<VarType> stack = data.getStack();
    int[][] arr = stack_impact[instr.opcode];

    if (arr != null) {
      // simple types only

      int[] read = arr[0];
      int[] write = arr[1];

      if (read != null) {
        int depth = 0;
        for (int type : read) {
          depth++;
          if (type == CodeConstants.TYPE_LONG ||
              type == CodeConstants.TYPE_DOUBLE) {
            depth++;
          }
        }

        stack.removeMultiple(depth);
      }

      if (write != null) {
        for (int type : write) {
          stack.push(new VarType(type));
          if (type == CodeConstants.TYPE_LONG ||
              type == CodeConstants.TYPE_DOUBLE) {
            stack.push(new VarType(CodeConstants.TYPE_GROUP2EMPTY));
          }
        }
      }
    }
    else {
      // Sonderbehandlung
      processSpecialInstructions(data, instr, pool);
    }
  }
public static void stepTypes(DataPoint data, Instruction instr, ConstantPool pool)