ParagonIE_Sodium_Core32_Curve25519::fe_mul

    public static function fe_mul(
        ParagonIE_Sodium_Core32_Curve25519_Fe $f,
        ParagonIE_Sodium_Core32_Curve25519_Fe $g
    ) {
        /**
         * @var ParagonIE_Sodium_Core32_Int32[] $f
         * @var ParagonIE_Sodium_Core32_Int32[] $g
         * @var ParagonIE_Sodium_Core32_Int64 $f0
         * @var ParagonIE_Sodium_Core32_Int64 $f1
         * @var ParagonIE_Sodium_Core32_Int64 $f2
         * @var ParagonIE_Sodium_Core32_Int64 $f3
         * @var ParagonIE_Sodium_Core32_Int64 $f4
         * @var ParagonIE_Sodium_Core32_Int64 $f5
         * @var ParagonIE_Sodium_Core32_Int64 $f6
         * @var ParagonIE_Sodium_Core32_Int64 $f7
         * @var ParagonIE_Sodium_Core32_Int64 $f8
         * @var ParagonIE_Sodium_Core32_Int64 $f9
         * @var ParagonIE_Sodium_Core32_Int64 $g0
         * @var ParagonIE_Sodium_Core32_Int64 $g1
         * @var ParagonIE_Sodium_Core32_Int64 $g2
         * @var ParagonIE_Sodium_Core32_Int64 $g3
         * @var ParagonIE_Sodium_Core32_Int64 $g4
         * @var ParagonIE_Sodium_Core32_Int64 $g5
         * @var ParagonIE_Sodium_Core32_Int64 $g6
         * @var ParagonIE_Sodium_Core32_Int64 $g7
         * @var ParagonIE_Sodium_Core32_Int64 $g8
         * @var ParagonIE_Sodium_Core32_Int64 $g9
         */
        $f0 = $f[0]->toInt64();
        $f1 = $f[1]->toInt64();
        $f2 = $f[2]->toInt64();
        $f3 = $f[3]->toInt64();
        $f4 = $f[4]->toInt64();
        $f5 = $f[5]->toInt64();
        $f6 = $f[6]->toInt64();
        $f7 = $f[7]->toInt64();
        $f8 = $f[8]->toInt64();
        $f9 = $f[9]->toInt64();
        $g0 = $g[0]->toInt64();
        $g1 = $g[1]->toInt64();
        $g2 = $g[2]->toInt64();
        $g3 = $g[3]->toInt64();
        $g4 = $g[4]->toInt64();
        $g5 = $g[5]->toInt64();
        $g6 = $g[6]->toInt64();
        $g7 = $g[7]->toInt64();
        $g8 = $g[8]->toInt64();
        $g9 = $g[9]->toInt64();
        $g1_19 = $g1->mulInt(19, 5); /* 2^4 <= 19 <= 2^5, but we only want 5 bits */
        $g2_19 = $g2->mulInt(19, 5);
        $g3_19 = $g3->mulInt(19, 5);
        $g4_19 = $g4->mulInt(19, 5);
        $g5_19 = $g5->mulInt(19, 5);
        $g6_19 = $g6->mulInt(19, 5);
        $g7_19 = $g7->mulInt(19, 5);
        $g8_19 = $g8->mulInt(19, 5);
        $g9_19 = $g9->mulInt(19, 5);
        /** @var ParagonIE_Sodium_Core32_Int64 $f1_2 */
        $f1_2 = $f1->shiftLeft(1);
        /** @var ParagonIE_Sodium_Core32_Int64 $f3_2 */
        $f3_2 = $f3->shiftLeft(1);
        /** @var ParagonIE_Sodium_Core32_Int64 $f5_2 */
        $f5_2 = $f5->shiftLeft(1);
        /** @var ParagonIE_Sodium_Core32_Int64 $f7_2 */
        $f7_2 = $f7->shiftLeft(1);
        /** @var ParagonIE_Sodium_Core32_Int64 $f9_2 */
        $f9_2 = $f9->shiftLeft(1);
        $f0g0    = $f0->mulInt64($g0, 27);
        $f0g1    = $f0->mulInt64($g1, 27);
        $f0g2    = $f0->mulInt64($g2, 27);
        $f0g3    = $f0->mulInt64($g3, 27);
        $f0g4    = $f0->mulInt64($g4, 27);
        $f0g5    = $f0->mulInt64($g5, 27);
        $f0g6    = $f0->mulInt64($g6, 27);
        $f0g7    = $f0->mulInt64($g7, 27);
        $f0g8    = $f0->mulInt64($g8, 27);
        $f0g9    = $f0->mulInt64($g9, 27);
        $f1g0    = $f1->mulInt64($g0, 27);
        $f1g1_2  = $f1_2->mulInt64($g1, 27);
        $f1g2    = $f1->mulInt64($g2, 27);
        $f1g3_2  = $f1_2->mulInt64($g3, 27);
        $f1g4    = $f1->mulInt64($g4, 30);
        $f1g5_2  = $f1_2->mulInt64($g5, 30);
        $f1g6    = $f1->mulInt64($g6, 30);
        $f1g7_2  = $f1_2->mulInt64($g7, 30);
        $f1g8    = $f1->mulInt64($g8, 30);
        $f1g9_38 = $g9_19->mulInt64($f1_2, 30);
        $f2g0    = $f2->mulInt64($g0, 30);
        $f2g1    = $f2->mulInt64($g1, 29);
        $f2g2    = $f2->mulInt64($g2, 30);
        $f2g3    = $f2->mulInt64($g3, 29);
        $f2g4    = $f2->mulInt64($g4, 30);
        $f2g5    = $f2->mulInt64($g5, 29);
        $f2g6    = $f2->mulInt64($g6, 30);
        $f2g7    = $f2->mulInt64($g7, 29);
        $f2g8_19 = $g8_19->mulInt64($f2, 30);
        $f2g9_19 = $g9_19->mulInt64($f2, 30);
        $f3g0    = $f3->mulInt64($g0, 30);
        $f3g1_2  = $f3_2->mulInt64($g1, 30);
        $f3g2    = $f3->mulInt64($g2, 30);
        $f3g3_2  = $f3_2->mulInt64($g3, 30);
        $f3g4    = $f3->mulInt64($g4, 30);
        $f3g5_2  = $f3_2->mulInt64($g5, 30);
        $f3g6    = $f3->mulInt64($g6, 30);
        $f3g7_38 = $g7_19->mulInt64($f3_2, 30);
        $f3g8_19 = $g8_19->mulInt64($f3, 30);
        $f3g9_38 = $g9_19->mulInt64($f3_2, 30);
        $f4g0    = $f4->mulInt64($g0, 30);
        $f4g1    = $f4->mulInt64($g1, 30);
        $f4g2    = $f4->mulInt64($g2, 30);
        $f4g3    = $f4->mulInt64($g3, 30);
        $f4g4    = $f4->mulInt64($g4, 30);
        $f4g5    = $f4->mulInt64($g5, 30);
        $f4g6_19 = $g6_19->mulInt64($f4, 30);
        $f4g7_19 = $g7_19->mulInt64($f4, 30);
        $f4g8_19 = $g8_19->mulInt64($f4, 30);
        $f4g9_19 = $g9_19->mulInt64($f4, 30);
        $f5g0    = $f5->mulInt64($g0, 30);
        $f5g1_2  = $f5_2->mulInt64($g1, 30);
        $f5g2    = $f5->mulInt64($g2, 30);
        $f5g3_2  = $f5_2->mulInt64($g3, 30);
        $f5g4    = $f5->mulInt64($g4, 30);
        $f5g5_38 = $g5_19->mulInt64($f5_2, 30);
        $f5g6_19 = $g6_19->mulInt64($f5, 30);
        $f5g7_38 = $g7_19->mulInt64($f5_2, 30);
        $f5g8_19 = $g8_19->mulInt64($f5, 30);
        $f5g9_38 = $g9_19->mulInt64($f5_2, 30);
        $f6g0    = $f6->mulInt64($g0, 30);
        $f6g1    = $f6->mulInt64($g1, 30);
        $f6g2    = $f6->mulInt64($g2, 30);
        $f6g3    = $f6->mulInt64($g3, 30);
        $f6g4_19 = $g4_19->mulInt64($f6, 30);
        $f6g5_19 = $g5_19->mulInt64($f6, 30);
        $f6g6_19 = $g6_19->mulInt64($f6, 30);
        $f6g7_19 = $g7_19->mulInt64($f6, 30);
        $f6g8_19 = $g8_19->mulInt64($f6, 30);
        $f6g9_19 = $g9_19->mulInt64($f6, 30);
        $f7g0    = $f7->mulInt64($g0, 30);
        $f7g1_2  = $g1->mulInt64($f7_2, 30);
        $f7g2    = $f7->mulInt64($g2, 30);
        $f7g3_38 = $g3_19->mulInt64($f7_2, 30);
        $f7g4_19 = $g4_19->mulInt64($f7, 30);
        $f7g5_38 = $g5_19->mulInt64($f7_2, 30);
        $f7g6_19 = $g6_19->mulInt64($f7, 30);
        $f7g7_38 = $g7_19->mulInt64($f7_2, 30);
        $f7g8_19 = $g8_19->mulInt64($f7, 30);
        $f7g9_38 = $g9_19->mulInt64($f7_2, 30);
        $f8g0    = $f8->mulInt64($g0, 30);
        $f8g1    = $f8->mulInt64($g1, 29);
        $f8g2_19 = $g2_19->mulInt64($f8, 30);
        $f8g3_19 = $g3_19->mulInt64($f8, 30);
        $f8g4_19 = $g4_19->mulInt64($f8, 30);
        $f8g5_19 = $g5_19->mulInt64($f8, 30);
        $f8g6_19 = $g6_19->mulInt64($f8, 30);
        $f8g7_19 = $g7_19->mulInt64($f8, 30);
        $f8g8_19 = $g8_19->mulInt64($f8, 30);
        $f8g9_19 = $g9_19->mulInt64($f8, 30);
        $f9g0    = $f9->mulInt64($g0, 30);
        $f9g1_38 = $g1_19->mulInt64($f9_2, 30);
        $f9g2_19 = $g2_19->mulInt64($f9, 30);
        $f9g3_38 = $g3_19->mulInt64($f9_2, 30);
        $f9g4_19 = $g4_19->mulInt64($f9, 30);
        $f9g5_38 = $g5_19->mulInt64($f9_2, 30);
        $f9g6_19 = $g6_19->mulInt64($f9, 30);
        $f9g7_38 = $g7_19->mulInt64($f9_2, 30);
        $f9g8_19 = $g8_19->mulInt64($f9, 30);
        $f9g9_38 = $g9_19->mulInt64($f9_2, 30);

        // $h0 = $f0g0 + $f1g9_38 + $f2g8_19 + $f3g7_38 + $f4g6_19 + $f5g5_38 + $f6g4_19 + $f7g3_38 + $f8g2_19 + $f9g1_38;
        $h0 = $f0g0->addInt64($f1g9_38)->addInt64($f2g8_19)->addInt64($f3g7_38)
            ->addInt64($f4g6_19)->addInt64($f5g5_38)->addInt64($f6g4_19)
            ->addInt64($f7g3_38)->addInt64($f8g2_19)->addInt64($f9g1_38);

        // $h1 = $f0g1 + $f1g0    + $f2g9_19 + $f3g8_19 + $f4g7_19 + $f5g6_19 + $f6g5_19 + $f7g4_19 + $f8g3_19 + $f9g2_19;
        $h1 = $f0g1->addInt64($f1g0)->addInt64($f2g9_19)->addInt64($f3g8_19)
            ->addInt64($f4g7_19)->addInt64($f5g6_19)->addInt64($f6g5_19)
            ->addInt64($f7g4_19)->addInt64($f8g3_19)->addInt64($f9g2_19);

        // $h2 = $f0g2 + $f1g1_2  + $f2g0    + $f3g9_38 + $f4g8_19 + $f5g7_38 + $f6g6_19 + $f7g5_38 + $f8g4_19 + $f9g3_38;
        $h2 = $f0g2->addInt64($f1g1_2)->addInt64($f2g0)->addInt64($f3g9_38)
            ->addInt64($f4g8_19)->addInt64($f5g7_38)->addInt64($f6g6_19)
            ->addInt64($f7g5_38)->addInt64($f8g4_19)->addInt64($f9g3_38);

        // $h3 = $f0g3 + $f1g2    + $f2g1    + $f3g0    + $f4g9_19 + $f5g8_19 + $f6g7_19 + $f7g6_19 + $f8g5_19 + $f9g4_19;
        $h3 = $f0g3->addInt64($f1g2)->addInt64($f2g1)->addInt64($f3g0)
            ->addInt64($f4g9_19)->addInt64($f5g8_19)->addInt64($f6g7_19)
            ->addInt64($f7g6_19)->addInt64($f8g5_19)->addInt64($f9g4_19);

        // $h4 = $f0g4 + $f1g3_2  + $f2g2    + $f3g1_2  + $f4g0    + $f5g9_38 + $f6g8_19 + $f7g7_38 + $f8g6_19 + $f9g5_38;
        $h4 = $f0g4->addInt64($f1g3_2)->addInt64($f2g2)->addInt64($f3g1_2)
            ->addInt64($f4g0)->addInt64($f5g9_38)->addInt64($f6g8_19)
            ->addInt64($f7g7_38)->addInt64($f8g6_19)->addInt64($f9g5_38);

        // $h5 = $f0g5 + $f1g4    + $f2g3    + $f3g2    + $f4g1    + $f5g0    + $f6g9_19 + $f7g8_19 + $f8g7_19 + $f9g6_19;
        $h5 = $f0g5->addInt64($f1g4)->addInt64($f2g3)->addInt64($f3g2)
            ->addInt64($f4g1)->addInt64($f5g0)->addInt64($f6g9_19)
            ->addInt64($f7g8_19)->addInt64($f8g7_19)->addInt64($f9g6_19);

        // $h6 = $f0g6 + $f1g5_2  + $f2g4    + $f3g3_2  + $f4g2    + $f5g1_2  + $f6g0    + $f7g9_38 + $f8g8_19 + $f9g7_38;
        $h6 = $f0g6->addInt64($f1g5_2)->addInt64($f2g4)->addInt64($f3g3_2)
            ->addInt64($f4g2)->addInt64($f5g1_2)->addInt64($f6g0)
            ->addInt64($f7g9_38)->addInt64($f8g8_19)->addInt64($f9g7_38);

        // $h7 = $f0g7 + $f1g6    + $f2g5    + $f3g4    + $f4g3    + $f5g2    + $f6g1    + $f7g0    + $f8g9_19 + $f9g8_19;
        $h7 = $f0g7->addInt64($f1g6)->addInt64($f2g5)->addInt64($f3g4)
            ->addInt64($f4g3)->addInt64($f5g2)->addInt64($f6g1)
            ->addInt64($f7g0)->addInt64($f8g9_19)->addInt64($f9g8_19);

        // $h8 = $f0g8 + $f1g7_2  + $f2g6    + $f3g5_2  + $f4g4    + $f5g3_2  + $f6g2    + $f7g1_2  + $f8g0    + $f9g9_38;
        $h8 = $f0g8->addInt64($f1g7_2)->addInt64($f2g6)->addInt64($f3g5_2)
            ->addInt64($f4g4)->addInt64($f5g3_2)->addInt64($f6g2)
            ->addInt64($f7g1_2)->addInt64($f8g0)->addInt64($f9g9_38);

        // $h9 = $f0g9 + $f1g8    + $f2g7    + $f3g6    + $f4g5    + $f5g4    + $f6g3    + $f7g2    + $f8g1    + $f9g0   ;
        $h9 = $f0g9->addInt64($f1g8)->addInt64($f2g7)->addInt64($f3g6)
            ->addInt64($f4g5)->addInt64($f5g4)->addInt64($f6g3)
            ->addInt64($f7g2)->addInt64($f8g1)->addInt64($f9g0);

        /**
         * @var ParagonIE_Sodium_Core32_Int64 $h0
         * @var ParagonIE_Sodium_Core32_Int64 $h1
         * @var ParagonIE_Sodium_Core32_Int64 $h2
         * @var ParagonIE_Sodium_Core32_Int64 $h3
         * @var ParagonIE_Sodium_Core32_Int64 $h4
         * @var ParagonIE_Sodium_Core32_Int64 $h5
         * @var ParagonIE_Sodium_Core32_Int64 $h6
         * @var ParagonIE_Sodium_Core32_Int64 $h7
         * @var ParagonIE_Sodium_Core32_Int64 $h8
         * @var ParagonIE_Sodium_Core32_Int64 $h9
         * @var ParagonIE_Sodium_Core32_Int64 $carry0
         * @var ParagonIE_Sodium_Core32_Int64 $carry1
         * @var ParagonIE_Sodium_Core32_Int64 $carry2
         * @var ParagonIE_Sodium_Core32_Int64 $carry3
         * @var ParagonIE_Sodium_Core32_Int64 $carry4
         * @var ParagonIE_Sodium_Core32_Int64 $carry5
         * @var ParagonIE_Sodium_Core32_Int64 $carry6
         * @var ParagonIE_Sodium_Core32_Int64 $carry7
         * @var ParagonIE_Sodium_Core32_Int64 $carry8
         * @var ParagonIE_Sodium_Core32_Int64 $carry9
         */
        $carry0 = $h0->addInt(1 << 25)->shiftRight(26);
        $h1 = $h1->addInt64($carry0);
        $h0 = $h0->subInt64($carry0->shiftLeft(26));
        $carry4 = $h4->addInt(1 << 25)->shiftRight(26);
        $h5 = $h5->addInt64($carry4);
        $h4 = $h4->subInt64($carry4->shiftLeft(26));

        $carry1 = $h1->addInt(1 << 24)->shiftRight(25);
        $h2 = $h2->addInt64($carry1);
        $h1 = $h1->subInt64($carry1->shiftLeft(25));
        $carry5 = $h5->addInt(1 << 24)->shiftRight(25);
        $h6 = $h6->addInt64($carry5);
        $h5 = $h5->subInt64($carry5->shiftLeft(25));

        $carry2 = $h2->addInt(1 << 25)->shiftRight(26);
        $h3 = $h3->addInt64($carry2);
        $h2 = $h2->subInt64($carry2->shiftLeft(26));
        $carry6 = $h6->addInt(1 << 25)->shiftRight(26);
        $h7 = $h7->addInt64($carry6);
        $h6 = $h6->subInt64($carry6->shiftLeft(26));

        $carry3 = $h3->addInt(1 << 24)->shiftRight(25);
        $h4 = $h4->addInt64($carry3);
        $h3 = $h3->subInt64($carry3->shiftLeft(25));
        $carry7 = $h7->addInt(1 << 24)->shiftRight(25);
        $h8 = $h8->addInt64($carry7);
        $h7 = $h7->subInt64($carry7->shiftLeft(25));

        $carry4 = $h4->addInt(1 << 25)->shiftRight(26);
        $h5 = $h5->addInt64($carry4);
        $h4 = $h4->subInt64($carry4->shiftLeft(26));
        $carry8 = $h8->addInt(1 << 25)->shiftRight(26);
        $h9 = $h9->addInt64($carry8);
        $h8 = $h8->subInt64($carry8->shiftLeft(26));

        $carry9 = $h9->addInt(1 << 24)->shiftRight(25);
        $h0 = $h0->addInt64($carry9->mulInt(19, 5));
        $h9 = $h9->subInt64($carry9->shiftLeft(25));

        $carry0 = $h0->addInt(1 << 25)->shiftRight(26);
        $h1 = $h1->addInt64($carry0);
        $h0 = $h0->subInt64($carry0->shiftLeft(26));

        return ParagonIE_Sodium_Core32_Curve25519_Fe::fromArray(
            array(
                $h0->toInt32(),
                $h1->toInt32(),
                $h2->toInt32(),
                $h3->toInt32(),
                $h4->toInt32(),
                $h5->toInt32(),
                $h6->toInt32(),
                $h7->toInt32(),
                $h8->toInt32(),
                $h9->toInt32()
            )
        );
    }