private void Sb3(int a, int b, int c, int d)
{
int t1 = a ^ b;
int t2 = a & c;
int t3 = a | d;
int t4 = c ^ d;
int t5 = t1 & t3;
int t6 = t2 | t5;
X2 = t4 ^ t6;
int t8 = b ^ t3;
int t9 = t6 ^ t8;
int t10 = t4 & t9;
X0 = t1 ^ t10;
int t12 = X2 & X0;
X1 = t9 ^ t12;
X3 = (b | d) ^ (t4 ^ t12);
}