bn_check_top(r);
int	BN_GF2m_mod_sqrt_arr(BIGNUM *r, const BIGNUM *a, const unsigned int p[], BN_CTX *ctx)	{	int ret = 0;	BIGNUM *u;		BN_CTX_start(ctx);	if ((u = BN_CTX_get(ctx)) == NULL) goto err;		if (!BN_zero(u)) goto err;	if (!BN_set_bit(u, p[0] - 1)) goto err;	ret = BN_GF2m_mod_exp_arr(r, a, u, p, ctx);  err:	BN_CTX_end(ctx);	return ret;	}