我这个程序有什么问题？？？

#include <reg52.h>
#define uchar unsigned char
#define uint unsigned int
sbit dula = P2^6;
sbit wela = P2^7;
sbit dawr = P3^6;
sbit dacs = P3^2;
sbit beep = P2^3;
uint m;
void delay(uint z)
{
    uint i,j;
    for(i = z;i > 0;i--)
    for(j = 110;j > 0;j--);
}
void main()
{
    uchar val,flag;
    dula = 0;
    wela = 0;
    dacs = 0;
    dawr = 0;
    P0 = 0;

   
    while(1)
    {   

        for(m = 0;m < 3;m++)
        if(flag == 0)
        {
            val += 5;
            P0 = val;
            if(val == 255)
            {
                 flag = 1;

            }
            delay(30);
        }
        else
        {
            val -= 5;
            P0 = val;
            if(val == 0)
            {
                flag = 0;
            }
            delay(30);
        }
        if(m == 2)
        {
        flag = 0;
        delay(9000);
        beep = 0;
        delay(100);
        beep = 1;
        }
       }

        }
   

            
        

我是想实现让D12灯均匀亮灭三次一共9秒，在三次之后蜂鸣器警报一次，但是我这个做了他只会到亮之后不灭了就一直最亮，然后蜂鸣器是可以9秒之后响一次。