# this is inside a 'use integer;' block 
sub mix4 ($$$) {
# per http://www.perlmonks.org/?node_id=1203705 this is a revised 32bit under 'use integer'; 
	$_[A] -= $_[B]; $_[A] -= $_[C]; { no integer; $_[A] ^= ($_[C]>>13); }
	$_[B] -= $_[C]; $_[B] -= $_[A]; { no integer; $_[B] ^= ($_[A]<< 8); } 
	$_[C] -= $_[A]; $_[C] -= $_[B]; { no integer; $_[C] ^= ($_[B]>>13); } 
	$_[A] -= $_[B]; $_[A] -= $_[C]; { no integer; $_[A] ^= ($_[C]>>12); } 
	$_[B] -= $_[C]; $_[B] -= $_[A]; { no integer; $_[B] ^= ($_[A]<<16); } 
	$_[C] -= $_[A]; $_[C] -= $_[B]; { no integer; $_[C] ^= ($_[B]>> 5); } 
	$_[A] -= $_[B]; $_[A] -= $_[C]; { no integer; $_[A] ^= ($_[C]>> 3); } 
	$_[B] -= $_[C]; $_[B] -= $_[A]; { no integer; $_[B] ^= ($_[A]<<10); } 
	$_[C] -= $_[A]; $_[C] -= $_[B]; { no integer; $_[C] ^= ($_[B]>>15); }
}