shiftLeft example

$return->limbs = array(
                (int) ($this->overflow & 0xffff),
                (int) ($this->limbs[0])
            );
            $return->overflow = $this->overflow >> 16;
            return $return->shiftRight($c & 15);
        }
        if ($c === 0) {
            $return->limbs = $this->limbs;
        } elseif ($c < 0) {
            /** @var int $c */
            return $this->shiftLeft(-$c);
        } else {
            if (!is_int($c)) {
                throw new TypeError();
            }
            /** @var int $c */
            // $return->limbs[0] = (int) (($this->limbs[0] >> $c) & 0xffff);             $carryLeft = (int) ($this->overflow & ((1 << ($c + 1)) - 1));
            $return->limbs[0] = (int) ((($this->limbs[0] >> $c) | ($carryLeft << (16 - $c))) & 0xffff);
            $carryRight = (int) ($this->limbs[0] & ((1 << ($c + 1)) - 1));
            $return->limbs[1] = (int) ((($this->limbs[1] >> $c) | ($carryRight << (16 - $c))) & 0xffff);
            $return->overflow >>= $c;
        }

$this->limbs[3], 0, 0, 0
                );
            } elseif ($c >= 32) {
                $return->limbs = array(
                    $this->limbs[2], $this->limbs[3], 0, 0
                );
            } else {
                $return->limbs = array(
                    $this->limbs[1], $this->limbs[2], $this->limbs[3], 0
                );
            }
            return $return->shiftLeft($c & 15);
        }
        if ($c === 0) {
            $return->limbs = $this->limbs;
        } elseif ($c < 0) {
            /** @var int $c */
            return $this->shiftRight(-$c);
        } else {
            if (!is_int($c)) {
                throw new TypeError();
            }
            /** @var int $carry */
            

/** @var int $mask */
        $mask = ~$mask;

        $h0 = $h0->mask($mask)->orInt32($g0);
        $h1 = $h1->mask($mask)->orInt32($g1);
        $h2 = $h2->mask($mask)->orInt32($g2);
        $h3 = $h3->mask($mask)->orInt32($g3);
        $h4 = $h4->mask($mask)->orInt32($g4);

        /* h = h % (2^128) */
        $h0 = $h0->orInt32($h1->shiftLeft(26));
        $h1 = $h1->shiftRight(6)->orInt32($h2->shiftLeft(20));
        $h2 = $h2->shiftRight(12)->orInt32($h3->shiftLeft(14));
        $h3 = $h3->shiftRight(18)->orInt32($h4->shiftLeft(8));

        /* mac = (h + pad) % (2^128) */
        $f = $h0->toInt64()->addInt64($this->pad[0]);
        $h0 = $f->toInt32();
        $f = $h1->toInt64()->addInt64($this->pad[1])->addInt($h0->overflow);
        $h1 = $f->toInt32();
        $f = $h2->toInt64()->addInt64($this->pad[2])->addInt($h1->overflow);
        $h2 = $f->toInt32();
        

    public static function fe_mul121666(ParagonIE_Sodium_Core32_Curve25519_Fe $f)
    {
        /** @var array<int, ParagonIE_Sodium_Core32_Int64> $h */
        $h = array();
        for ($i = 0; $i < 10; ++$i) {
            $h[$i] = $f[$i]->toInt64()->mulInt(121666, 17);
        }

        $carry9 = $h[9]->addInt(1 << 24)->shiftRight(25);
        $h[0] = $h[0]->addInt64($carry9->mulInt(19, 5));
        $h[9] = $h[9]->subInt64($carry9->shiftLeft(25));

        $carry1 = $h[1]->addInt(1 << 24)->shiftRight(25);
        $h[2] = $h[2]->addInt64($carry1);
        $h[1] = $h[1]->subInt64($carry1->shiftLeft(25));

        $carry3 = $h[3]->addInt(1 << 24)->shiftRight(25);
        $h[4] = $h[4]->addInt64($carry3);
        $h[3] = $h[3]->subInt64($carry3->shiftLeft(25));

        $carry5 = $h[5]->addInt(1 << 24)->shiftRight(25);
        $h[6] = $h[6]->addInt64($carry5);
        

/** @var ParagonIE_Sodium_Core32_Int32 $h8 */
        $h8 = ParagonIE_Sodium_Core32_Int32::fromInt(
            self::load_3(self::substr($s, 26, 3)) << 4
        );
        /** @var ParagonIE_Sodium_Core32_Int32 $h9 */
        $h9 = ParagonIE_Sodium_Core32_Int32::fromInt(
            (self::load_3(self::substr($s, 29, 3)) & 8388607) << 2
        );

        $carry9 = $h9->addInt(1 << 24)->shiftRight(25);
        $h0 = $h0->addInt32($carry9->mulInt(19, 5));
        $h9 = $h9->subInt32($carry9->shiftLeft(25));

        $carry1 = $h1->addInt(1 << 24)->shiftRight(25);
        $h2 = $h2->addInt32($carry1);
        $h1 = $h1->subInt32($carry1->shiftLeft(25));

        $carry3 = $h3->addInt(1 << 24)->shiftRight(25);
        $h4 = $h4->addInt32($carry3);
        $h3 = $h3->subInt32($carry3->shiftLeft(25));

        $carry5 = $h5->addInt(1 << 24)->shiftRight(25);
        $h6 = $h6->addInt32($carry5);