proteus仿真 数码管的小数点为什么会被点亮？

极大可能g段和dp段短路了

#include<reg52.h>
#define uchar unsigned char#define uint unsigned intuchar code table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};
sbit dula=P2^6;
sbit wela=P2^7;
sbit key1=P3^4;
sbit key2=P3^5;
sbit key3=P3^6;
sbit key4=P3^7;
uint t0;uchar num;
void delayms(uint);
void init();
void keyscan();
void display(uchar num);
void main()
{
init();
while(1)
{
keyscan();
display(num);
}
}
void display(uchar num)
{
uchar shi,ge;
shi=num/10;
ge=num%10;
dula=1;
P0=table[shi];
dula=0;
P0=0xff;
wela=1;
P0=0xfe;
wela=0;
delayms(50);
dula=1;
P0=table[ge];
dula=0;
P0=0xff;
wela=1;
P0=0xfd;
wela=0;
delayms(50);
}
void delayms(uint xms)
{
uint x,y;
for(x=90;x>0;x--)
for(y=xms;y>0;y--);
}
void init()
{
TMOD=0x02;
TH0=6;
TL0=6;
EA=1;
ET0=1;
}
void T0_timer() interrupt 1
{
t0++;
if(t0==4000)
{
t0=0;
num++;
if(num==60)
num=0;
}
}
void keyscan()
{
if(key1==0)
{
delayms(10);
if(key1==0)
num++;
if(num==60)
num=0;
while(!key1);
}
if(key2==0)
{
delayms(10);
if(key2==0)
num--;
if(num==0)
num=60;
while(!key2);
}
if(key3==0)
{
delayms(10);
if(key3==0)
num=0;
while(!key3);
}
if(key4==0)
{
delayms(10);
if(key4==0)
TR0=~TR0;
while(!key4);
}
}