Looking for article: microprogrammed DIY TTL calculator

[Brent Hilpert]

On 2017-Mar-20, at 6:58 AM, Jacek Greniger via cctalk wrote:
> Hi,
> 
> Two years ago I've found scans in PDF with the article (dated 197?, I don't
> remember) describing DIY TTL-based calculator. This was microprogrammed
> machine (if I remember correctly microproprogram was "stored" in the diode
> array). It has LED display and possiblity to calculate square root.
> Definitely not talking about EDUC-8 computer from 1975. I think this
> calculator was published a little bit earlier.
> 
> Unfortunately I'm no longer able to find it. Does anyone associate the name of
> that magazine?


There's this one:
	http://bitsavers.trailing-edge.com/pdf/practicalElectronics/digi-cal/Digi-Cal_Jul72-May73.pdf

I haven't looked at it in depth, but cursorily it looks like a way-behind-the-times (then) architecture -
it looks like it's doing multiplication by exhaustive iteration, for example.
One could reimplement a 1960s desktop calc design in TTL and be ahead.