GEN
rnormal(long prec)
{
	pari_sp ltop = avma;
	GEN u1, u2, left, right, ret;
	u1 = randomr(prec);
	u2 = randomr(prec);
	left = sqrtr_abs(shiftr(mplog(u1), 1));
	right = mpcos(mulrr(shiftr(mppi(prec), 1), u2));

	ret = mulrr(left, right);
	ret = gerepileupto(ltop, ret);
	return ret;
}