[16:55:37] # iximeow:~> yaxdis a01234123412341234
0x00000000: a01234123412341234: mov al, byte [0x3412341234123412]
[16:55:39] # iximeow:~> yaxdis 4fa01234123412341234
0x00000000: 4fa01234123412341234: mov r8b, byte [0x3412341234123412]
... rex.b does not influence the register like that. i noticed this because i accidentally fixed it, and then wanted to see if i fixed a bug or introduced a bug. turns out i fixed a bug by accident. oops.