#pragma GCC optimize "-Og"
#include "ArduinoTrace.h"

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  PORTD=PORTD|(1<<PD4);        //board pin 4 pull-up resistor
  DDRB=DDRB|(1<<PB0);          //led pin output
}

void loop() {
  // put your main code here, to run repeatedly:
  asm volatile(
    "sbis %0,4 \n"
    "rjmp L10 \n"
    "rjmp L20 \n"

    "L10:"
    "sbi %1, 0\n"
    "rjmp L30\n"
    "L20:"
    "cbi %1, 0\n"
    "L30:"
    :
    :"I" (_SFR_IO_ADDR(PIND)), "I" (_SFR_IO_ADDR(PORTB))
  );
  delay(100);
}