func benchDouble(curve elliptic.Curve, n int) {
x := curve.Params().Gx
y := curve.Params().Gy
for i := 0; i < n; i++ {
curve.Double(x, y)
}
}
func testDoubleAndAdd(curve elliptic.Curve, x1, y1, ex, ey *big.Int) bool {
x, y := curve.Double(x1, y1)
x, y = curve.Add(x, y, x1, y1)
return x.Cmp(ex) == 0 && y.Cmp(ey) == 0
}