It's definitely 32-bit only, but structurally it's simple enough that converting to 64-bit might not be a huge effort (and the kernel is only about 6kloc of .c

It's definitely 32-bit only, but structurally it's simple enough that converting to 64-bit might not be a huge effort (and the kernel is only about 6kloc of .c files). I haven't done x86 systems stuff since 64bit became common, so it might be a fun way to learn about what's different.