/* this+=this */
public int dbl()
{
if (INF)
{
return(-1);
}
if (y.iszilch())
{
inf();
return(-1);
}
FP2 w1 = new FP2(x);
FP2 w2 = new FP2(0);
FP2 w3 = new FP2(x);
FP2 w8 = new FP2(x);
w1.sqr();
w8.copy(w1);
w8.imul(3);
w2.copy(y);
w2.sqr();
w3.copy(x);
w3.mul(w2);
w3.imul(4);
w1.copy(w3);
w1.neg();
// w1.norm();
x.copy(w8);
x.sqr();
x.add(w1);
x.add(w1);
x.norm();
z.mul(y);
z.add(z);
w2.add(w2);
w2.sqr();
w2.add(w2);
w3.sub(x);
y.copy(w8);
y.mul(w3);
// w2.norm();
y.sub(w2);
y.norm();
z.norm();
return(1);
}
/* set this=-this */
public void neg()
{
FP2 m = new FP2(a);
FP2 t = new FP2(0);
m.add(b);
m.neg();
m.norm();
t.copy(m);
t.add(b);
b.copy(m);
b.add(a);
a.copy(t);
}
/* Calculate RHS of twisted curve equation x^3+B/i */
public static FP2 RHS(FP2 x)
{
x.norm();
FP2 r = new FP2(x);
r.sqr();
FP2 b = new FP2(new BIG(ROM.CURVE_B));
b.div_ip();
r.mul(x);
r.add(b);
r.reduce();
return(r);
}
/* normalise all components of this mod Modulus */
public void norm()
{
a.norm();
b.norm();
}