Well, in my case, it was on a bit-addressable machine
expressed as hex.
So taking a bit address, adding a byte, word or halfword (3, 6 or 5
bit implied shift) index and propagating the carries to 48 bits was a
bit more than I was prepared to do mentally, particularly at the end of
a 6 hour session in a noisy machine room.
Ah yes... That is the sort of thing the HP16C is excellent at, and the
reason I keep it on my electronics worknench.
Although I must say I like the RPL machines too. The 'large as you need'
stack is IMHO a lot nicer than the fixed 4 level one. And the bit
operations are almost as good as those on the 16C. Certainly enough for
what I normally need.
-tony