#include "stm32f4xx.h"

// Define macros for enabling GPIO clocks
#define GPIOAEN (1U<<0)  // Enable clock for GPIOA
#define GPIOCEN (1U<<2)  // Enable clock for GPIOC

// Define macros for GPIO pins
#define PIN5 (1U<<5)     // Pin 5
#define PIN13 (1U<<13)   // Pin 13

// Simple delay function
void delay(int duration){
    for(int i = 0; i < duration; i++) {
        // Busy-wait delay
    }
}

int main(void){
    // Enable GPIOA and GPIOC clocks
    RCC->AHB1ENR |= GPIOAEN;
    RCC->AHB1ENR |= GPIOCEN;

    // Set PA5 as output (00: input, 01: output)
    GPIOA->MODER &= ~(3U << (5 * 2)); // Clear mode bits for PA5
    GPIOA->MODER |= (1U << (5 * 2));  // Set PA5 to output mode

    // Set PC13 as input (default mode)
    GPIOC->MODER &= ~(3U << (13 * 2)); // Ensure PC13 is set as input

    while (1) {
        // Check if PC13 is high
        if (GPIOC->IDR