OPENCORES.ORG

For positive integer exponents, and very large numbers, the


----- Original Message ----- 
From: Steven R. McQueen<srmcqueen@m...> 
To: 
Date: Fri Nov 25 19:05:18 CET 2005 
Subject: [oc] Exponential 

> For positive integer exponents, and very large numbers, the 
> BasicRSA 
> project implements a square-and-multiply algorithm for modular 
> exponentiation. It uses two copies of a shift-and-add multiplier, 
> one to 
> do modular squares, and one to do modular multiplication of 
> dissimilar 
> numbers. You have to do a square for every bit position in the 
> exponent, 
> and multiply the square by the result of the multiplication (hint, 
> start 
> with 1) every time the exponent bit position is 1. 
> Testing can be a real pain, since you have to calculate all the 
> exponents used in your test set and compare the correct results 
> with 
> whatever your core produces. I don't know a shortcut for that. 
> -- 
> Steven R. McQueen 
> Phone: (951) 809-3232 
> Email: srmcqueen at mcqueentech.com 
> Web: www.mcqueentech.com 
> On Fri, 2005-11-25 at 17:23 +0100, oceanfrea at hotmail.com wrote: 
> > Hi, I would like to ask if anyone implement exponential 
> calculation in 
> > vhdl and how to go about doing the algorithm. Most 
> importantly, how to 
> > test the algorithm if it is working properly. Thanks. 
> > _______________________________________________ 
> > http://www.opencores.org/mailman/listinfo/cores 
> 
> what about negative integer exponents? Can I implement the same 
stuff as you had mentioned?