Re: IBM 1620 invalid character symbol

From: Ken Whistler via Unicode <unicode_at_unicode.org>
Date: Tue, 26 Sep 2017 08:53:50 -0700

Philippe,

Those aren't negative digits, per se. The usage in the manual is with an
overline (or macron) to indicate the flag bit. It does occur over a
zero, and in explanation in the text of floating point operations, it is
also shown over letters (X, M, E) representing digits of the exponent
and mantissa. See p. 27 (31 of the pdf) in that same manual, for an
extensive discussion with lots of examples in the text:

http://www.bitsavers.org/pdf/ibm/1620/A26-5706-3_IBM_1620_CPU_Model_1_Jul65.pdf

The Unicode representation of the text material printed on that page
would best be done with a combining macron, I think.

--Ken

On 9/26/2017 6:34 AM, Philippe Verdy via Unicode wrote:
> But what is interesting is the use of negative digits (-1 to -9, with
> the minus sign above the digit; I've not seen a case of minus 0, not
> needed apparently by the described operations)
> How do you encode these negative decimal digits in Unicode ? with a
> macron diacritic ?
>
Received on Tue Sep 26 2017 - 10:54:24 CDT

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