#include "reg52.h"
sbit k0=P1^2;
sbit k1=P1^3;
sbit k2=P1^4;
sbit k3=P1^5;
bit k=0,kk=0;
void main()
{
unsigned char Xd=0;
unsigned int ys=0;
while(1)
{
if(k0==0&&++Xd==0){kk=0;k=P3=1;while(k0==0);}
if(k1==0&&++Xd==0){kk=k=0;P3=255;while(k1==0);}
if(k2==0&&++Xd==0){kk=k=P3=1;while(k2==0);}
if(k3==0&&++Xd==0){kk=1;k=0;P3=128;while(k3==0);}
if(++ys==0)
{
if(kk)
{
if(k)if((P3*=2)==0)P3=1;else;
else if((P3/=2)==0)P3=128;else;
}
else
if(k)if((P3*=2)==0)P3=1;else;
}
}
}
