Path: utzoo!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!ames!pacbell!att!homxb!houxs!beyer
From: beyer@houxs.ATT.COM (J.BEYER)
Newsgroups: comp.arch
Subject: Re: String lengths
Summary: What about the 7090 Convert instructions?
Message-ID: <1185@houxs.ATT.COM>
Date: 9 Feb 89 22:42:52 GMT
References: <8882@alice.UUCP> <22036@ism780c.isc.com>
Organization: AT&T BL Holmdel NJ USA
Lines: 23

In article <22036@ism780c.isc.com>, news@ism780c.isc.com (News system) writes:
> The 7090 provided no instructions for accessing individual characters.  The
> notion of characters existed only at the I/O interface where 6 characters
> (in 6 bit BCD) could be read into a single 36 bit word.  The minimum transfer
> was two words.  I am not aware of any languages made available by IBM that
> provided a string data type.  In fact the limit of 6 character identifiers in
> FORTRAN was due to the fact that 6 characters could be manipulated as a word
> on the 7090 (and on the 704 the original "FORTRAN" machine).
This may be quibbling, but did not the Convert By Replacement From MQ
and similar instructions deal with 6-bit characters on the 7090? I know
they were not in the 704. Perhaps they did not get there until the 7094.
But they were not full-fledged character manipulation primitives, I agree.
It has been at least 20 years since I programmed one of those.

As I recall, the GE635 and 645 did have ways to address either 6 or 9 bit
characters (programmer's choice), using clever addressing and tally modes.
I am even more hazy about that machine, though.


-- 
Jean-David Beyer
A.T.&T., Holmdel, New Jersey, 07733
houxs!beyer