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From: jgd@csd4.milw.wisc.edu (John G Dobnick)
Newsgroups: comp.arch
Subject: Re: Registers in memory
Message-ID: <3602@csd4.milw.wisc.edu>
Date: 29 Jul 89 06:13:39 GMT
References: <8907281547.AA28878@maxwell.ece.cmu.edu>
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From article <8907281547.AA28878@maxwell.ece.cmu.edu>, by mbjr@maxwell.ece.cmu.edu (Mauricio Breternitz):
> 	The (now ancient) IBM 1130 also had the three index registers
> at memory locations 1, 2, 3

The (even more ancient) IBM 1620 (model II) not only had index registers
in memory (reasonable, since it was a memory-to-memory machine), but it
had two software-selectable "banks" of them.  "Software-selectable" meaning
the program could select one bank, the other bank, or *neither* bank of
index registers.  One could also programatically turn indirect addressing
on or off.   And, of course, it used base-10 arithmetic -- none of this
binary nonsense!

Interesting machine.
-- 
John G Dobnick
Computing Services Division @ University of Wisconsin - Milwaukee
INTERNET: jgd@csd4.milw.wisc.edu
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"Knowing how things work is the basis for appreciation,
and is thus a source of civilized delight."  -- William Safire