Would you like signs with those chars?

https://trofi.github.io/posts/203-signed-char-or-unsigned... has some investigation on this issue. Turns out there are quite a few architectures that only provide zero extending byte loads but the ABI has chosen char's to be signed, thus requiring an extra instruction to patch it up.

(That blog post is a few years old and doesn't include results for RISC-V, but I understand that RISC-V is like ARM, in that it provides both zero extending and sign extending byte loads but the ABI has chosen char's to be unsigned)