ParagonIE_Sodium_Core_X25519::fe_cswap( ParagonIE_Sodium_Core_Curve25519_Fe $f, ParagonIE_Sodium_Core_Curve25519_Fe $g, int $b = 0 ): void

23    public static function fe_cswap(24        ParagonIE_Sodium_Core_Curve25519_Fe $f,25        ParagonIE_Sodium_Core_Curve25519_Fe $g,26        $b = 027    ) {28        $b = -$b;29        $x0 = ($f->e0 ^ $g->e0) & $b;30        $x1 = ($f->e1 ^ $g->e1) & $b;31        $x2 = ($f->e2 ^ $g->e2) & $b;32        $x3 = ($f->e3 ^ $g->e3) & $b;33        $x4 = ($f->e4 ^ $g->e4) & $b;34        $x5 = ($f->e5 ^ $g->e5) & $b;35        $x6 = ($f->e6 ^ $g->e6) & $b;36        $x7 = ($f->e7 ^ $g->e7) & $b;37        $x8 = ($f->e8 ^ $g->e8) & $b;38        $x9 = ($f->e9 ^ $g->e9) & $b;39        $f->e0 ^= $x0;40        $f->e1 ^= $x1;41        $f->e2 ^= $x2;42        $f->e3 ^= $x3;43        $f->e4 ^= $x4;44        $f->e5 ^= $x5;45        $f->e6 ^= $x6;46        $f->e7 ^= $x7;47        $f->e8 ^= $x8;48        $f->e9 ^= $x9;49        $g->e0 ^= $x0;50        $g->e1 ^= $x1;51        $g->e2 ^= $x2;52        $g->e3 ^= $x3;53        $g->e4 ^= $x4;54        $g->e5 ^= $x5;55        $g->e6 ^= $x6;56        $g->e7 ^= $x7;57        $g->e8 ^= $x8;58        $g->e9 ^= $x9;59    }