replaced power operator with shift operator

Again the performance benefit doesn't seem to outweigh the readability:

```
$ python3.4 -m timeit "(1048576 & 0x7f) | 0x80"
100000000 loops, best of 3: 0.0197 usec per loop
$ python3.4 -m timeit "(1048576 % 128) + 128"
100000000 loops, best of 3: 0.0199 usec per loop
```