求助！我的dfs哪里错了？

#include <bits/stdc++.h>
using namespace std;

int mp[99][99];
int n = 0, m = 0, stx = 0, sty = 0, T = 0;
int sum = 0;

void dfs(int x, int y) {
	if (mp[x][y] == 1) {
		return ;
	}
	int cnt = 0;
	mp[x][y]=1;
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= m; j++) {
			if (mp[i][j] == 1) {
				cnt++;
			}
		}
	}
	if (cnt == (n * m)) {
		sum++;
		return;
	}
	dfs(x + 1, y - 2);
	dfs(x + 2, y - 1);
	dfs(x - 2, y + 1);
	dfs(x + 1, y + 2);
	dfs(x - 1, y + 2);
	dfs(x - 2, y + 1);
	dfs(x - 2, y - 1);
	dfs(x - 1, y - 2);
}

int main() {
	cin >> T;
	for (int a = 0; a < T; a++) {
		sum = 0;

		cin >> n >> m;
		for (int i = 0; i <= n + 1; i++) {
			mp[0][i] = 1;
		}
		for (int i = 0; i <= n + 1; i++) {
			mp[i][0] = 1;
		}
		cin >> stx >> sty;
		stx++;
		sty++;
		dfs(stx, sty);
		cout << sum;
	}
	return 0;
}