[Info-vax] DEC VAX 8650

[gah4]

On Thursday, February 9, 2023 at 4:35:22 PM UTC-8, Don North wrote:

(snip)

> "Fernando Cristino Colon Osorio is a Puerto Rican engineer, inventor, educator, 
> and entrepreneur who is currently the executive director of the Wireless Systems 
> Security Research Laboratory (WSSRL). In 1975 he was the primary architect of 
> Digital Equipment Corporation (DEC) PDP 11/60 floating point unit. The FP11E 
> incorporated the Newton-Raphson method as a mechanism to accelerate floating 
> point division by a factor of 6X.  

I suspect the algorithm that IBM used for the 360/91.

It is a favorite for discussing in books on pipelined processors.
Though you only use it if you already have a high speed multiplier.

The 360/91 does floating point double precision add in 2 cycles,
multiply in 3, single precision divide in 12, and double precision in 18.