#include <stdint.h>

#define GPIO_BASE 0x40000000u
#define VOUT_BASE 0x40000004u

static volatile uint32_t * const gpio = (volatile uint32_t *)GPIO_BASE;
static volatile uint32_t * const vout = (volatile uint32_t *)VOUT_BASE;

static void delay(volatile uint32_t ticks){
    while (ticks--) {
        __asm__ volatile ("nop");
    }
}

int main(void)
{
    uint32_t v = 0;

    for (;;) {
        for(int i=0; i<1000; i++){
            *vout = v;
            v++;
            delay(5u);
        }
        *gpio ^= 0xffffffff;
    }
}