#define led *((volatile byte*) 0x25)
#define ledD *((volatile byte*) 0x24)

void Delay(long a){
  for(long i = 0; i < a; i++){
    asm("");
  }
}

int main(){
  ledD = 0x1F;
  while(1){
    led = 0x01;
    Delay(1000000);
    led = 0x02;
    Delay(1000000);
    led = 0x04;
    Delay(1000000);
    led = 0x08;
    Delay(1000000);
    led = 0x10;
    Delay(1000000);
  }
  return 0;
}