[RC5] A whole bunch of things

gindrup at okway.okstate.edu gindrup at okway.okstate.edu
Thu Nov 20 19:45:17 EST 1997


     Nope.  Get an IEEE doubbe (80 bit mantissa).  Put two adjacent copies 
     of the argument in the most significant bytes (setting the other two 
     bytes to 0).  Call the byte position collections occupied by the two 
     copies "high-order" and "low-order" indicating the relative 
     significance of their bits.  Set the exponent to represent 2^-(32-k).  
     Add 1.  This slides the bits we originally inserted by 32-k bits to 
     the right.  The bits in the position called "low-order" are now the 
     original argument shifted k bits to the left.
     If you want right shift, set the exponent to represent 2^-k instead.
            -- Eric Gindrup ! gindrup at okway.okstate.edu


______________________________ Reply Separator _________________________________
Subject: Re: [RC5] A whole bunch of things 
Author:  <rc5 at llamas.net > at SMTP
Date:    1997/11/20 10:20



[snip]
actually,......NO!
check the rsa-page for the algorithm and you will see...
it needs a lotta shifting, rotating and stuff. try that on a fpu.
alright, you could do <fmul 2^x>/<fdiv 2^x> for shifting, but it woudn't be 
worth the time spent to implement it, would it??
     
Eric Schaefer
Team 'Dresden University of Technology'
     
     [snip]


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