rc4-x86_64.pl: fix due credit.

# May 2011

#

# The only code path that was not modified is P4-specific one. New

# AMD code path is inspired by and Intel optimization is heavily

# based on submission from Maxim Locktyukhin of Intel. Current

# performance in cycles per processed byte (less is better) and

# improvement coefficients relative to previous version of this

# module are:

# The only code path that was not modified is P4-specific one. Non-P4

# Intel code path optimization is heavily based on submission by Maxim

# Perminov, Maxim Locktyukhin and Jim Guilford of Intel. I've used

# some of the ideas even in attempt to optmize the original RC4_INT

# code path... Current performance in cycles per processed byte (less

# is better) and improvement coefficients relative to previous

# version of this module are:

#

# Opteron	5.3/+0%

# P4		6.5

# Sandy Bridge	4.2/+120%

# Atom		9.3/+80%

#

# (*)	Note that this result is ~15% lower than result for 32-bit

#	code, meaning that it's possible to improve it, but it's

#	more than likely at the cost of the others...

# (*)	Note that Core2 result is ~15% lower than corresponding result

#	for 32-bit code, meaning that it's possible to improve it,

#	but more than likely at the cost of the others (see rc4-586.pl

#	to get the idea)...

$flavour = shift;

$output  = shift;