哪位单片机高手帮我分析下面红色区域这段程序（详细一...

#include <reg51.h>

#define uchar unsigned char

#define uint  unsigned int

sbit SH_CP=P2^1;

sbit DS=P2^0;

sbit ST_CP=P2^2;

sbit  s=P2^4;

sbit  clk=P2^5;

uchar code tab[ ]=  

{

0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,

0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,/*" ",0*/

0x00,0x00,0x20,0x00,0x17,0xFC,0x10,0x40,0x80,0x40,0x40,0x40,0x48,0x40,0x08,0x40,

0x10,0x40,0x10,0x40,0xE0,0x40,0x20,0x40,0x20,0x40,0x2F,0xFE,0x20,0x00,0x00,0x00,/*"江",0*/

0x00,0x00,0x7D,0xFC,0x45,0x04,0x49,0x04,0x49,0x04,0x51,0xFC,0x49,0x04,0x49,0x04,

0x45,0x04,0x45,0xFC,0x45,0x04,0x69,0x04,0x52,0x04,0x42,0x04,0x44,0x14,0x48,0x08,/*"阴",1*/

0x22,0x08,0x11,0x08,0x11,0x10,0x00,0x20,0x7F,0xFE,0x40,0x02,0x80,0x04,0x1F,0xE0,

0x00,0x40,0x01,0x80,0xFF,0xFE,0x01,0x00,0x01,0x00,0x01,0x00,0x05,0x00,0x02,0x00,/*"学",2*/

0x00,0x40,0x78,0x20,0x4B,0xFE,0x52,0x02,0x54,0x04,0x61,0xF8,0x50,0x00,0x48,0x00,

0x4B,0xFE,0x48,0x90,0x68,0x90,0x50,0x90,0x41,0x12,0x41,0x12,0x42,0x0E,0x44,0x00,/*"院",3*/

};

uchar num,temp,temp1,temp2;

//顺向、逐列、阴码  MICROSOFT SANS SERIF 字宽32 字高25   MATRIX-8X8-GREEN  左旋90度 左右翻转

//                MATRIX-8X8-RED    右旋90度 上下翻转

void delay_ms(unsigned int ms)

{

uchar j;

while(ms--)

for(j=0;j<123;j++);

}

void WriteByte(uchar dat)  

{

uchar k;

for(k=0;k<8;k++)

{

  dat=dat>>1;

  DS=CY;

  SH_CP=0;

  SH_CP=1;

}

}

void disp_up()

{

uchar i,m,k;

for(k=0;k<4;k++)//4个字符（含空格）

for(i=0;i<16;i++)

{

  for(m=0;m<4;m++) //重复显示4次

for(num=0;num<16;num++) //每字16字节

  {

   if(i<8)

   {

    temp1=tab[2*num+k*32]<<i; //前字节左移i位

    temp1|=tab[2*num+1+k*32]>>8-i;//或后字节的最高位

    temp2=tab[2*num+1+k*32]<<i;

    temp2|=tab[2*num+32*(k+1)]>>8-i;//或下一字前字节的最高位

   }

   else

   {

    temp1=tab[2*num+1+k*32]<<i-8;

    temp1|=tab[2*num+32*(k+1)]>>8-i+8;

    temp2=tab[2*num+32*(k+1)]<<i-8;

    temp2+=tab[2*num+1+32*(k+1)]>>8-i+8;

   }   

   WriteByte(temp2);

   WriteByte(temp1);

   P1=temp;

           clk=0;

              clk=1;

              s=1;

   ST_CP=0;

   ST_CP=1;

   delay_ms(1);

   temp++;

   if(temp==16)

   {temp=0;

     s=0;

       }

  }

}

}

void main()

{     uint  t;

       for(t=0;t>16;t++)

         {

           clk=0;

              clk=1;

         }

         s=0;

while(1)

{

   temp=0;// 不加此条，流动飞快

   disp_up();

}

}