Online PHP editor | refs for 7AIOa

<?php /** * Since integers in 32-bit PHP 5.x are signed, exclusively, this only goes up to 2147483647 */ function add_32bit($intA, $intB) { if (!is_int($intA) || !is_int($intB)) { return false; } if ($intA > 2147483647 || $intB > 2147483647) { return false; } $sum = 0; $carry = 0; $rem = 0; for ($i = 0; $i < 4; ++$i) { $oA = $intA >> ($i * 8); $oB = $intB >> ($i * 8); $pA = $oA & 0xff; $pB = $oB & 0xff; $tmp = ($pA + $pB + $carry); $rem = $tmp & 0xff; $carry = ($tmp - $rem) >> 8; $inc = ($rem << ($i * 8)); $sum |= $inc & 0x7fffffff; } return $sum; } // Tests var_dump( add_32bit(1000, 1001) ); var_dump( add_32bit(1000, 2000) ); var_dump( add_32bit(1, 1) ); var_dump( add_32bit(10000000, 10000000) ); var_dump( 2147483646, 1 ); var_dump( 2147483646, 2 ); var_dump( 2147483646, 3 ); var_dump( 2147483646, 4 );