求助一段程序过于抢答器

#include<reg51.h>
#define uchar unsigned char
#define uint unsigned int
sbit speak=P2^0;
sbit host=P2^2;
uchar GroupNo;
uchar code Seg7code[9]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f};//0到8的代码

void delay1ms(void)//延迟1毫秒
{uchar i;
for(i=250;i>0;i--);
}

void ShowG(uchar no)//显示出第几组
{P1=Seg7code[no];}

uchar KeySweep(void)//键盘扫描,获取组数
{uchar temp,no=0;
if(P3!=0xff)
  {delay1ms();
   if(P3!=0xff)
    temp=~P3;
  }
while(temp!=0)
  {temp=temp>>1;
   no++;
  }
return no;
}

void timer0(void) interrupt 1
{TH0=0x10;
TL0=0X60;
speak=~speak;
}

void InitTime0(void)//定时器0初始化
{TMOD=0x02;
TH0=0x10;
TL0=0X60;
ET0=1;
TR0=1;
}

void main()
{InitTime0();
while(1)
{P3=0xff;
  ShowG(0);
  while(P3==0xff);
  GroupNo=KeySweep();
  ShowG(GroupNo);
  EA=1;
  while(host==1);
  delay1ms();
  while(host==1);
  EA=0;
}
}

   
扫描键盘的程序谁给解释下，有没有更好更简单的算法来替代