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);
        $f1_2 = $f1->shiftLeft(1);
        $f3_2 = $f3->shiftLeft(1);
        $f5_2 = $f5->shiftLeft(1);
        $f7_2 = $f7->shiftLeft(1);
        $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);