Function addMixed [src]

Add secp256k1 points, the second being specified using affine coordinates.

Prototype

pub fn addMixed(p: Secp256k1, q: AffineCoordinates) Secp256k1

Parameters

p: Secp256k1q: AffineCoordinates

Source

  pub fn addMixed(p: Secp256k1, q: AffineCoordinates) Secp256k1 {
    var t0 = p.x.mul(q.x);
    var t1 = p.y.mul(q.y);
    var t3 = q.x.add(q.y);
    var t4 = p.x.add(p.y);
    t3 = t3.mul(t4);
    t4 = t0.add(t1);
    t3 = t3.sub(t4);
    t4 = q.y.mul(p.z);
    t4 = t4.add(p.y);
    var Y3 = q.x.mul(p.z);
    Y3 = Y3.add(p.x);
    var X3 = t0.dbl();
    t0 = X3.add(t0);
    // b3 = (2^2)^2 + 2^2 + 1
    const t2_4 = p.z.dbl().dbl();
    var t2 = t2_4.dbl().dbl().add(t2_4).add(p.z);
    var Z3 = t1.add(t2);
    t1 = t1.sub(t2);
    const Y3_4 = Y3.dbl().dbl();
    Y3 = Y3_4.dbl().dbl().add(Y3_4).add(Y3);
    X3 = t4.mul(Y3);
    t2 = t3.mul(t1);
    X3 = t2.sub(X3);
    Y3 = Y3.mul(t0);
    t1 = t1.mul(Z3);
    Y3 = t1.add(Y3);
    t0 = t0.mul(t3);
    Z3 = Z3.mul(t4);
    Z3 = Z3.add(t0);

    var ret = Secp256k1{
        .x = X3,
        .y = Y3,
        .z = Z3,
    };
    ret.cMov(p, @intFromBool(q.x.isZero()));
    return ret;
}  