void init_port(void);
void outport(char );
unsigned char button(void);
void glow(void);
void dely(int );
void setup() 
{
  init_port();
  glow();
}
void glow()
{
  unsigned char btn;
  while(1)
  {
    btn=button();
    //outport(btn);
    for(char i=0;i<8;i++)
    {
      if(btn==(1<<i))
      {
        outport(1<<i);
        break;
      }
    }
    delay(30);
  }
  
}
unsigned char button()
{
  volatile char *inport_c=(char *)0x26;
  volatile char *inport_b=(char *)0x23;
  unsigned char b,c;
  while((*inport_c==0)&&(*inport_b==0));
  c=*inport_c;b=*inport_b;
  if(c!=0x00)
  {
    return c & 0x3F;
  }
  else
  {
    return ((b>>3) & 0x03)<<6;
  }
}
void init_port()
{
  char *dir_port_d=(char *)0x2A;
  char *dir_port_b=(char *)0x24;
  char *dir_port_c=(char *)0x27;
  *dir_port_d=0xFC;
  *dir_port_b=0x03;
  *dir_port_c=0x00;
}
void outport(char outdata)
{
  char *outport_d=(char *)0x2B;
  char *outport_b=(char *)0x25;
  *outport_d= outdata << 2;
  *outport_b= outdata >> 6;
}
void dely(int num)
{
  volatile int i;
  while(num)
  {
    for(i=0;i<100;i++);
    num-=1;
  }
}
void loop() {
  // put your main code here, to run repeatedly:

}