I think the opcode subfield length determining the
display radix of a
system is a red herring. Because the Atmel AVR microcontrollers have
32 8-bit registers, should base-32 be used as the display radix?
What is wrong with base 32 :-)
Mroe seriously, there are undoubtedly many instruction sets that are no
easier to decode whether written in hex or octal. And for those it makes
no difference which you use. But there are soem that are a lot easier to
understnad in one number system than in the other, and for those it makes
sense, at least to me, to use said number ssytem. The PDP11 is one such.
It's easy to hand-assemble/disassemble when written in octal, a lot
harder when written in hex.
-tony