#include <cstdint>

struct Gpio {
    volatile uint32_t data;
};

#define gpio0 ((Gpio*)0x40000000)

void sleep(int ms) {
    for (int m = 0; m < ms; m++) {
        for (int i = 0; i < 10000; i++) {
            asm volatile ( "" );
        }
    }
}

int main() {
    int out = 0;

    while (1) {
        gpio0->data = out;
        out = (out + 1) % 256;

        sleep(10);
    }
}