#include<reg52.h>
	#define uchar unsigned char
	#define uint unsigned int
	char a[16]={0};
	char b[16]={0};
	uchar dm[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x79,0x40};
	uchar wx[]={0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80};
	uchar m,n,l,smz1,smz,zhi,flag,cp;
	char i,j,k;
	bit flag1,flag2,flag3;
	sbit key1=P1^3;
	sbit key2=P1^2;
	void delay()
	{
		for(i=0;i<100;i++);
	}
	void jia()
	{
		for(i=0;i<16;i++)
		{
			a[i]=a[i]+b[i]+cp;
			if(a[i]>=10)
			{
				a[i]=a[i]-10;
				cp=1;
			}
			else
				cp=0;
		}
	}
	void jian()
	{
		flag3=0;
		for(i=15;i>=0;i--)
			{
				if(a[i]==b[i])
					continue;	
				else if(a[i]>b[i])
				{
					flag3=1;
					break;
				}
				else
					break;
				
			}
		if(flag3==1)
		{
			for(i=0;i<16;i++)
			{
				a[i]=a[i]-cp-b[i];
				if(a[i]<0)
				{
					a[i]=a[i]+10;
					cp=1;
				}
				else
					cp=0;
			}
			for(i=15;i>=0;i--)
				if(a[i]!=0)
				{
					a[i+1]=11;
					break;
				}		
		 }
		else
		{
			for(i=0;i<16;i++)
			{
				a[i]=b[i]-cp-a[i];
				if(a[i]<0)
				{
					a[i]=10+a[i];
					cp=1;	
				}
				else
					cp=0;
			}
		}
	}
	void chen()
	{

	}
	void chu()
	{

	}
	uchar key()
	{
		P2=0x0f;
		smz=P2;
		P2=0xf0;
		smz1=P2;
		smz=smz+smz1;
		return smz;
	}

	void js()
	{
		cp=0;
		switch(flag) 
		{
			case 0xfe: jia();break;
			case 0xfd: jian();break;
			case 0xfc: chen();break;
			case 0xfb: chu();break;
		}
	}

	void ys()
	{	
		flag1=1;
		if(zhi==0xee)
		{
			js();
			flag2=1;
		}
		else
		{
			js();
			flag=zhi;
			flag2=0;
		}
		for(j=0;j<16;j++)
		{
			b[j]=a[j];
			a[j]=0;
		}
	}

	void yw()
	{
		flag1=0;
		m=0;
		if(flag2==1)
		{
			for(i=0;i<16;i++)
				b[i]=0;
		  	flag2=0;
		}
		if(a[7]==0)
		{
			for(i=6;i>0;i--)
				a[i+1]=a[i];
			a[1]=a[0];
			a[0]=zhi;
		}
	}

	void pd()
	{
		switch(key())
		{	
			case 0xff:zhi=10;break;
			case 0xed:zhi=1;while(key()==0xed);break;
			case 0xdd:zhi=2;while(key()==0xdd);break;
			case 0xbd:zhi=3;while(key()==0xbd);break;
			case 0xeb:zhi=4;while(key()==0xeb);break;
			case 0xdb:zhi=5;while(key()==0xdb);break;
			case 0xbb:zhi=6;while(key()==0xbb);break;
			case 0xe7:zhi=7;while(key()==0xe7);break;
			case 0xd7:zhi=8;while(key()==0xd7);break;
			case 0xb7:zhi=9;while(key()==0xb7);break;
			case 0xde:zhi=0;while(key()==0xde);break;
			case 0xee:zhi=0xff;while(key()==0xee);break;
			case 0x7e:zhi=0xfe;while(key()==0x7e);break;
			case 0x7d:zhi=0xfd;while(key()==0x7d);break;
			case 0x7b:zhi=0xfc;while(key()==0x7b);break;
			case 0x77:zhi=0xfb;while(key()==0x77);break;
			case 0xbe:zhi=0xee;while(key()==0xbe);break;
		}

		if(zhi==0xff)
		{
			m=0;
			for(j=0;j<16;j++)
			{
				a[j]=0;
				b[j]=0;
			}
		}
		else if(zhi==0xfe||zhi==0xfd||zhi==0xfc||zhi==0xfb||zhi==0xee)
		{
			ys();
		}
		else if(zhi==10);	
		else
		{
			yw();
		}
	}

	void display()
	{
		if(flag1==0)
		{
			for(j=15;j>0;j--)
			{
				if(a[j]!=0)
				{
					if(j>=8)
					{
						a[0]=10;
						for(i=1;i<8;i++)
							a[i]=0;
						m=0;
						break;
					}
					m=j;
					break;
				}
			}
			for(j=0;j<m+1;j++)
			{
				n=a[j];
				P0=~dm[n];
				key1=1;
				key1=0;
				P0=wx[j];
				key2=1;
				key2=0;
				delay();
			}
		}
		else
		{
			for(j=15;j>0;j--)
			{
				if(b[j]!=0)
				{
					if(j>=8)
					{
						b[0]=10;
						for(i=1;i<8;i++)
							b[i]=0;
						m=0;
						break;
					}
					m=j;
					break;
				}
			}
			for(j=0;j<m+1;j++)
			{
				n=b[j];
				P0=~dm[n];
				key1=1;
				key1=0;
				P0=wx[j];
				key2=1;
				key2=0;
				delay();
			}
		}		
	}
 	void main()
	{
		flag1=0;
		cp=0;
		m=0;
		flag=0xfe;
		while(1)
		{
			pd();
			display();
		}
	}