Sujet : Re: "CDR down the list..."
De : nmh (at) *nospam* sraddha.invalid (Nils M Holm)
Groupes : comp.lang.lisp sci.lang alt.usage.englishSuivi-à : comp.lang.lispDate : 11. Jul 2024, 10:35:42
Autres entêtes
Organisation : TARFU
Message-ID : <lf9jquF9lngU1@mid.individual.net>
References : 1 2 3 4
User-Agent : tin/2.6.1-20211226 ("Convalmore") (FreeBSD/12.4-RELEASE (amd64))
In comp.lang.lisp Aidan Kehoe <
kehoea@parhasard.net> wrote:
?Contents of the decrement register,? wasn?t it? Not horrific on that front.
Content of the Decrement part of a Register. Some instructions on the
704 divided 36-bit words into four parts: prefix, decrement, tag, and
address:
-3-|-------15------|-3-|-------15------
PPP DDDDDDDDDDDDDDD TTT AAAAAAAAAAAAAAA
CAR and CDR extracted the D(ecrement) and A(ddress) parts. Because the
machine had 15 address lines, a CONS could be stored in a single machine
word. Personally, I like the names CAR and CDR and how they extend, e.g.
CADR, CDDR, etc.
-- Nils M Holm < n m h @ t 3 x . o r g > http://t3x.org