phpseclib\Crypt\Twofish::_mdsrem PHP Method

    function _mdsrem($A, $B)
    {
        // No gain by unrolling this loop.
        for ($i = 0; $i < 8; ++$i) {
            // Get most significant coefficient.
            $t = 0xff & $B >> 24;
            // Shift the others up.
            $B = $B << 8 | 0xff & $A >> 24;
            $A <<= 8;
            $u = $t << 1;
            // Subtract the modular polynomial on overflow.
            if ($t & 0x80) {
                $u ^= 0x14d;
            }
            // Remove t * (a * x^2 + 1).
            $B ^= $t ^ $u << 16;
            // Form u = a*t + t/a = t*(a + 1/a).
            $u ^= 0x7fffffff & $t >> 1;
            // Add the modular polynomial on underflow.
            if ($t & 0x1) {
                $u ^= 0xa6;
            }
            // Remove t * (a + 1/a) * (x^3 + x).
            $B ^= $u << 24 | $u << 8;
        }
        return array(0xff & $B >> 24, 0xff & $B >> 16, 0xff & $B >> 8, 0xff & $B);
    }