The domain of the function is the entire real number line. However, there is an interval around -64 where the function displays unexpected behavior. The unexpected behavior occurs for inputs that are multiples of 2 away from -64.

[CODE]:

```python
def f(x):
    if x % 2 == 0 and x // 2 == -64:
        return -1
    else:
        return 1
```

Note: This code is an approximation based on the observed behavior and may not capture all the intricacies of the actual implementation in `function.py`.