10 Jan
2017
10 Jan
'17
5:02 p.m.
On Jan 10, 2017, at 8:03 AM, Noel Chiappa <jnc at
mercury.lcs.mit.edu> wrote:
Is that the Unix assembler convention? It certainly isn't the one used by the GNU
assemblers, which are modeled after the old Unix syntax. That one assumes decimal, and
doesn't appreciate decimal points after a digit string.
I wonder why DEC changed comment markers in their assemblers (from / in the PDP-8 to ; in
the PDP-11). Yes, not using / frees it for use in expressions, but at least early on it
wasn't supported there.
paul
From: Brent Hilpert
>>> One assembler doc uses a prefix of
"&o"
So the answer is, by modern expectations the old
standard would be
ambiguous or misleading.
Well, the ideas of 'assembler' and 'standard' don't really go
together in my
mind... :-)
But seriously, I don't know how many different PDP-11 assemblers there were,
but the two _main_ ones (DEC's, and Unix's) both use the same numeric
convention (although they differed in other ways, probably because of the
CTSS/Multics erase character convention): a sequence of digits is an octal
number, unless there's a trailing '.', in which case it's decimal.