Function dbl [src]

Double a secp256k1 point.

Prototype

pub fn dbl(p: Secp256k1) Secp256k1

Parameters

p: Secp256k1

Source

  pub fn dbl(p: Secp256k1) Secp256k1 {
    var t0 = p.y.sq();
    var Z3 = t0.dbl();
    Z3 = Z3.dbl();
    Z3 = Z3.dbl();
    var t1 = p.y.mul(p.z);
    var t2 = p.z.sq();
    // b3 = (2^2)^2 + 2^2 + 1
    const t2_4 = t2.dbl().dbl();
    t2 = t2_4.dbl().dbl().add(t2_4).add(t2);
    var X3 = t2.mul(Z3);
    var Y3 = t0.add(t2);
    Z3 = t1.mul(Z3);
    t1 = t2.dbl();
    t2 = t1.add(t2);
    t0 = t0.sub(t2);
    Y3 = t0.mul(Y3);
    Y3 = X3.add(Y3);
    t1 = p.x.mul(p.y);
    X3 = t0.mul(t1);
    X3 = X3.dbl();
    return .{
        .x = X3,
        .y = Y3,
        .z = Z3,
    };
}  