[threePointFive]

I had to check this because my intuition told me that this would generate a warning. GCC and Clang both warn about that assignment with -Wsign-conversion, however that doesn't seem to be enabled with any of -Wall, -Wextra, or -Wpendatic and only clang's -Weverthing would catch it if you weren't specifically looking for it.

[gpderetta]

that's because assigning -1 to an unsigned number is an idiomatic, safe and portable way to setting all bits to 1. You could argue that an explicit cast should be warranted in this case, and I sort of agree, but it would break way too much code.