James J. Besemer
jb at cascade-sys.com
Sun Sep 29 09:35:38 CEST 2002
David LeBlanc wrote:
>In fact, the names of some Lisp funtions came from the machine registers of
>the same name: car (current address register) and cdr (current data
>register) are the only ones I recall offhand.
Yup. It was from IBM's 709/7094 computer.
Some Lisps had a 3rd, "CSR" but I don't recall the name of the register.
Being able to branch in yet a third direction did not add as much
utility as the first two. And it didn't translate as well to most other
It was nevertheless implemented in one CDC Lisp I am aware of, where 60
bit words and 18 bit addresses left plenty of room for 3 addresses (with
bits left over) in a cell.
James J. Besemer 503-280-0838 voice
2727 NE Skidmore St. 503-280-0375 fax
Portland, Oregon 97211-6557 mailto:jb at cascade-sys.com
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