//Azmi Abdurrahman Kautsar_1103223211_TK-46-06
#include "stm32f1xx.h"
#define LED_PIN 7        
#define BUTTON_PIN 11    

int main(void) {
  RCC->APB2ENR |= RCC_APB2ENR_IOPAEN;

  // configure button
  GPIOA->CRH &= ~(GPIO_CRH_MODE11 | GPIO_CRH_CNF11);
  GPIOA->CRH |= GPIO_CRH_CNF11_1; 
  GPIOA->ODR |= (1 << BUTTON_PIN); 

  // configure led
  GPIOA->CRL &= ~(GPIO_CRL_MODE7 | GPIO_CRL_CNF7);
  GPIOA->CRL |= GPIO_CRL_MODE7_0; 
    
  while (1) {
    if (!(GPIOA->IDR & (1 << BUTTON_PIN))) {
      GPIOA->BSRR = (1 << LED_PIN);    
    } else {
      GPIOA->BSRR = (1 << (LED_PIN + 16)); 
    }
  }
}