#include <reg51.h>
#include <intrins.h>
sbit S1=P3^1;
sbit S2=P3^0;
sbit S3=P3^2;
sbit S4=P3^3;
void delay(unsigned int i)
{
	unsigned int k;
	for(k=0;k<i;k++);
}
void main()
{
	unsigned char a;
	P2=0xFF;
		
	while(1)
	{
		if(S1==0 && S2!=0)
		{
			delay(1200);
			if(S1==0 && S2!=0)
			{
				P2=0xF0;//低四位亮
			}
		}
		else if(S1!=0 && S2==0)
		{
			delay(1200);
			if(S1!=0 && S2==0)
			{
				P2=0x0F;//高四位亮
			}
		}
		else if(S1==0 && S2==0)
		{
			delay(1200);
			if(S1==0 && S2==0)
			{
				P2=0x00;//都亮
			}
		}
		else if(S3==0)
		{
			delay(1200);
			a=0x55;
			if(S3==0)
			{
				P2=a;//交叉亮
				delay(5000);
				P2=~a;//交叉亮
				delay(5000);
			}
		}
		else if(S4==0)
		{
			delay(1200);
			P2=0x7F;
			while(S4==0)
			{
				P2=_cror_(P2,1); //循环右移
				delay(5000);
			}
		}
		else if(S1!=0&&S2!=0&&S3!=0&&S4!=0)
		{
			P2=0xFF;//没按不亮
		}
	}
}