ParagonIE_Sodium_Core32_Int64::subInt

    public function subInt($int)
    {
        ParagonIE_Sodium_Core32_Util::declareScalarType($int, 'int', 1);
        $int = (int) $int;

        $return = new ParagonIE_Sodium_Core32_Int64();
        $return->unsignedInt = $this->unsignedInt;

        /** @var int $carry */
        $carry = 0;
        for ($i = 3; $i >= 0; --$i) {
            /** @var int $tmp */
            $tmp = $this->limbs[$i] - (($int >> 16) & 0xffff) + $carry;
            /** @var int $carry */
            $carry = $tmp >> 16;
            $return->limbs[$i] = (int) ($tmp & 0xffff);
        }
        return $return;
    }