新手求指导啊 - - Powered by Discuz!

#include<reg51.h>
#include<intrins.h>
#define uchar unsigned char
#define uint unsigned int
uchar code table[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90} ;
uchar a=0,b=0,c=0,d=0,num=0;
void xs();
void main()
{
   TH0=(65536-30000)/256;
   TL0=(65536-30000)%256;
   TMOD=0X01;
   EA=1;
   ET0=1;
   TR0=1;
   xs();
   while(1)
   {
         if(num==4)
     {   num=0; a++;
        if(a==10)
     {a=0;b++; }
        if(b==10)
         {b=0;c++;}
     if(c==10)
         {c=0;d++;}
     if(d==10)
         d=0;
           xs();
   }
   }
}
void xs()
{
   uchar m,n=1;
   for(m=0;m<4;m++)
   {    P2=_crol_(n,m);
       switch(m)
      {
          case 0 :P0=table[a];break;
       case 1 :P0=table;break;
       case 2 :P0=table[c];break;
       case 3 :P0=table[d];break;
      }
   }
}
void time() interrupt 1
{
    TH0=(65536-30000)/256;
          TL0=(65536-30000)%256;
    num++;
}动态显示0-9999为什么数码管上显示不出来啊？