3v4l.org

run code in 300+ PHP versions simultaneously
<?php $bits32 = 32; $bits64 = 64; $N32 = 0xfffffffe; $N64 = 0xfffffffffffffffe; $result = -( pow(2, $bits32) - $N32 ); echo $result,"\n"; echo pow(2,$bits32) , "\n",$N32; $result = -( pow(2, $bits64) - $N64 ); echo $result,"\n"; echo pow(2,$bits64), "\n",$N64;

preferences:
33.9 ms | 402 KiB | 5 Q