ZZn6 line(ECn3& A,ECn3& C,ECn3& B,int type,ZZn3& slope,ZZn3& ex1,ZZn3& ex2,ZZn& Px,ZZn& Py)
{
ZZn6 w;
ZZn3 d;
#ifdef AFFINE
ZZn3 x,y;
A.get(x,y);
d.set1(Py);
w=shuffle(y-slope*(Px+x),d);
#endif
#ifdef PROJECTIVE
ZZn3 x,y,z,z3,t;
C.getZ(z3);
d.set1(Py);
if (type==MR_ADD)
{ // exploit that B is in affine
ZZn3 x2,y2;
B.get(x2,y2);
y2*=z3; d*=z3;
w=shuffle(y2-slope*(Px+x2),d);
}
if (type==MR_DOUBLE)
{ // use extra information from point doubling
A.get(x,y,z);
w=shuffle(ex1-slope*(Px*ex2+x),d*z3*ex2);
}
#endif
return w;
}
ZZn6 gp(ZZn3* ptable,int &j,ZZn& Px,ZZn& Py)
{
ZZn6 w;
ZZn3 d;
d.set1(Py);
w=shuffle(ptable[j]*Px+ptable[j+1],d);
j+=2;
return w;
}