byte specifiers

[Earl A. Killian <EAK at MIT-MC>]

Can someone explain to me the byte functions take a byte
specifier which encodes the position and size rather than just
taking two separate arguments?  The first thing that comes to
mind is because that's the way the pdp10 (and lispm too?) do it,
which is not much of a reason.

The other reason I can think of is so that you can pass them
around as arguments with one parameter instead of two, but that's
not very compelling either.