private void Sb7(int a, int b, int c, int d)
{
int t1 = b ^ c;
int t2 = c & t1;
int t3 = d ^ t2;
int t4 = a ^ t3;
int t5 = d | t1;
int t6 = t4 & t5;
X1 = b ^ t6;
int t8 = t3 | X1;
int t9 = a & t4;
X3 = t1 ^ t9;
int t11 = t4 ^ t8;
int t12 = X3 & t11;
X2 = t3 ^ t12;
X0 = (~t11) ^ (X3 & X2);
}