I actually thought of that when I wrote my comment. But still, notice that (1) the instructions take as their input registers that point to the data (ie. a cha

I actually thought of that when I wrote my comment. But still, notice that (1) the instructions take as their input registers that point to the data (ie. a char pointer), not some machine-level idea of a "string", and (2) the cost of these instructions is still O(n), even though you don't have to write the loop manually.