rc4-x86_64.pl: "Westmere" optimization.

# fit for Core2 and therefore the code was modified to skip cloop8 on

# this CPU.

# Intel Westmere was observed to perform suboptimally. Adding yet

# another movzb to cloop1 improved performance by almost 50%! Core2

# performance is improved too, but nominally...

$flavour = shift;

$output  = shift;

if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }

.align	16

.Lcloop1:

	add	$TX[0]#b,$YY#b

	movzb	$YY#b,$YY#d

	movzb	($dat,$YY),$TY#d

	movb	$TX[0]#b,($dat,$YY)

	movb	$TY#b,($dat,$XX[0])