zInvSq := new(p256Element)

	for j := 0; j < 32; j++ {
		p.Add(p, base)

		// Convert p to affine coordinates.
		p256Inverse(zInv, &p.z)
		p256Sqr(zInvSq, zInv, 1)
		p256Mul(zInv, zInv, zInvSq)

		p256Mul(&p.x, &p.x, zInvSq)
		p256Mul(&p.y, &p.y, zInv)
		p.z = p256One

		if p256Equal(&table[j].x, &p.x) != 1 || p256Equal(&table[j].y, &p.y) != 1 {
			t.Fatalf("incorrect table entry at index %d", j)
		}
	}

	return e
}

// Sub sets e = t1 - t2, and returns e.
func (e *P256Element) Sub(t1, t2 *P256Element) *P256Element {
	p256Sub(&e.x, &t1.x, &t2.x)
	return e
}

// Mul sets e = t1 * t2, and returns e.
func (e *P256Element) Mul(t1, t2 *P256Element) *P256Element {
	p256Mul(&e.x, &t1.x, &t2.x)
	return e
}

// Square sets e = t * t, and returns e.
func (e *P256Element) Square(t *P256Element) *P256Element {

func (e *P224Element) Sub(t1, t2 *P224Element) *P224Element {
	p224Sub(&e.x, &t1.x, &t2.x)
	return e
}

// Mul sets e = t1 * t2, and returns e.
func (e *P224Element) Mul(t1, t2 *P224Element) *P224Element {
	p224Mul(&e.x, &t1.x, &t2.x)
	return e
}

// Square sets e = t * t, and returns e.
func (e *P224Element) Square(t *P224Element) *P224Element {
	p224Square(&e.x, &t.x)
	return e
}

func (e *P521Element) Sub(t1, t2 *P521Element) *P521Element {
	p521Sub(&e.x, &t1.x, &t2.x)
	return e
}

// Mul sets e = t1 * t2, and returns e.
func (e *P521Element) Mul(t1, t2 *P521Element) *P521Element {
	p521Mul(&e.x, &t1.x, &t2.x)
	return e
}

// Square sets e = t * t, and returns e.
func (e *P521Element) Square(t *P521Element) *P521Element {
	p521Square(&e.x, &t.x)
	return e
}