谁能帮我看看这个矩阵键盘问题出在哪里了，瞅了两天了

#include <reg52.h>
#define uchar unsigned char
#define uint unsigned int
sbit dula=P1^0;
uchar code table[]={0xfc,0x60,0xda,0xf2,0x66,0xb6,0xbe,
0xe0,0xfe,0xf6,0xee,0x3e,};
void delayms(uint xms)
{
uint i,j;
for(i=xms;i>0;i--)
for(j=110;j>0;j--);
} void display(uchar num)
{
P0=table[num];
dula=1;
dula=0;
} void matrixkeyscan()
{
uchar temp,key; P3=0xfe;
temp=P3;
temp=temp&0xf8;
if(temp!=0xf8)
{
delayms(10);
temp=P3;
if(temp!=0xf8)
{
temp=P3;
switch(temp)
{
case 0xf6:
key=0;
break;
case 0xee:
key=1;
break;
case 0xde:
key=2;
break;
case 0xbe:
key=3;
break;
}
while(temp!=0xf8)
{
temp=P3;
temp=temp&0xf8;
}
display(key);
}
} P3=0xfd;
temp=P3;
temp=temp&0xf8;
if(temp!=0xf8)
{
delayms(10);
temp=P3;
if(temp!=0xf8)
{
temp=P3;
switch(temp)
{
case 0xf5:
key=4;
break;
case 0xed:
key=5;
break;
case 0xdd:
key=6;
break;
case 0xbd:
key=7;
break;
}
while(temp!=0xf8)
{
temp=P3;
temp=temp&0xf8;
}
display(key);
}
} P3=0xfb;
temp=P3;
temp=temp&0xf8;
if(temp!=0xf8)
{
delayms(10);
temp=P3;
if(temp!=0xf8)
{
temp=P3;
switch(temp)
{
case 0xf3:
key=8;
break;
case 0xeb:
key=9;
break;
case 0xdb:
key=10;
break;
case 0xbb:
key=11;
break;
}
while(temp!=0xf8)
{
temp=P3;
temp=temp&0xf8;
}
display(key);
}
}
}
void main()
{
P0=0;
dula=1;
dula=0;
P2=0;
while(1)
{
matrixkeyscan();
}
}
不能正常显示，。