Interested in UNIVAC 9000 Series (and IBM 360)
cclist at sydex.com
Fri Nov 18 18:04:48 CST 2016
On 11/18/2016 03:15 PM, Jon Elson wrote:
> OH, yeah! Besides the limited instruction set, short registers only
> half populated, etc., did you know that the 360/20 did not have an
> adder? It could only increment/decrement. The data paths were only
> 4 bits wide, so to add a 3 in register A to a 5 in register B, it
> decremented A and incremented B until A went negative. It did this
> for each nibble. I'm guessing a 16-bit add took over 100 us. I'd
> ALMOST reject calling this a COMPUTER!
So not even as smart as a 1620 CADET, which did arithmetic via TLU?
I guess I could believe that for register arithmetic, but did it do the
same for memory-to-memory packed decimal operations?
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