[求助]单片机八位数码管显示问题（从0~F）

#include<reg52.h>
#define uint unsigned int
#define uchar unsigned char
sbit dula=P2^6;
sbit wela=P2^7;
uchar num;
uchar code table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,
         0x77,0x7c,0x39,0x5e,0x79,0x71};   
void delay(uint z);
void main()
 {
   wela=1;
   P0=0xc0;
   wela=0;
   while(1)
     {
       for(num=0;num<16;num++)
         {    dula=1;
              P0=table[num];
              dula=0;
              delay(1000);
          }
      }
 }              
void delay(uint z)
{   
   uint x,y;
   for(x=z;x>0;x--)
      for(y=110;y>0;y--);
}