mandelbrot PHP program

<?php
/* The Computer Language Benchmarks Game
   https://salsa.debian.org/benchmarksgame-team/benchmarksgame/
   contributed by Thomas GODART (based on Greg Buchholz's C program) 
   modified by anon
*/

ob_implicit_flush(1);
ob_start(NULL, 4096);


$h = ($argc == 2) ? ((int)$argv[1]) : 600;
$w = $h;

printf ("P4\n%d %d\n", $w, $h);

$bit_num = 128;
$byte_acc = 0;

$yfac = 2.0 / $h;
$xfac = 2.0 / $w;

for ($y = 0 ; $y < $h ; ++$y)
{
   $result = array('c*');

   $Ci = $y * $yfac - 1.0;

   for ($x = 0 ; $x < $w ; ++$x)
   {
      $Zr = 0; $Zi = 0; $Tr = 0; $Ti = 0.0;

      $Cr = $x * $xfac - 1.5;

      do {
         for ($i = 0 ; $i < 50 ; ++$i)
         {
            $Zi = 2.0 * $Zr * $Zi + $Ci;
            $Zr = $Tr - $Ti + $Cr;
            $Tr = $Zr * $Zr;
            if (($Tr+($Ti = $Zi * $Zi)) > 4.0) break 2;
         }
         $byte_acc += $bit_num;
      } while (FALSE);

      if ($bit_num === 1) {
         $result[] = $byte_acc;
         $bit_num = 128;
         $byte_acc = 0;
      } else {
         $bit_num >>= 1;
      }
   }
   if ($bit_num !== 128) {
      $result[] = $byte_acc;
      $bit_num = 128;
      $byte_acc = 0;
   }
   echo call_user_func_array('pack', $result);
}

    

NOTES:
64-bit Ubuntu quad core
PHP 8.3.3 (cli)
(built: Mar  3 2024 08:47:21) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.3.3,
with Zend OPcache v8.3.3,
Copyright (c) Zend Technologies


 Fri, 08 Mar 2024 23:49:42 GMT

COMMAND LINE:
 /opt/src/php-8.3.3/bin/php -dzend_extension=/opt/src/php-8.3.3/lib/php/extensions/no-debug-non-zts-20230831/opcache.so -dopcache.enable_cli=1 -dopcache.jit_buffer_size=64M -n  mandelbrot.php 16000

(BINARY) PROGRAM OUTPUT NOT SHOWN