谁能帮我解释一下这个程序每一步都是什么意思？？是关于单片机流水灯的

#include<reg52.h>
sbit led1=P1^0;
sbit led2=P1^1;
sbit led3=P1^2;
sbit led4=P1^3;
sbit led5=P1^4;
sbit led6=P1^5;
sbit led7=P1^6;
sbit led8=P1^7;
void delay()
{
unsigned int i;
for(i=0;i<9000;i++);
}
void main()
{
while(1)
{
led1=0;
delay();
led1=1;
delay();
led2=0;
delay();
led2=1;
delay();
led3=0;
delay();
led3=1;
delay();
led4=0;
delay();
led4=1;
delay();
led5=0;
delay();
led5=1;
delay();
led6=0;
delay();
led6=1;
delay();
led7=0;
delay();
led7=1;
delay();
led8=0;
delay();
led8=1;
delay();
}
}

我帮你答。
#include<reg52.h>
sbit led1=P1^0;//定义LED1为P1.0引脚，下面也一样
sbit led2=P1^1;
sbit led3=P1^2;
sbit led4=P1^3;
sbit led5=P1^4;
sbit led6=P1^5;
sbit led7=P1^6;
sbit led8=P1^7;
void delay()//延时程序
{
unsigned int i;
for(i=0;i<9000;i++);
}
void main()
{
while(1)//这是一个死循环，就是程序一直走
{
led1=0;1#灯亮（假设是阴极接单片机I/O)
delay();延时
led1=1;1#灯灭
delay();延时
led2=0;2#灯亮（以下同）
delay();
led2=1;
delay();
led3=0;
delay();
led3=1;
delay();
led4=0;
delay();
led4=1;
delay();
led5=0;
delay();
led5=1;
delay();
led6=0;
delay();
led6=1;
delay();
led7=0;
delay();
led7=1;
delay();
led8=0;
delay();
led8=1;
delay();
}
}