#include "systick.h"

volatile uint32_t systick_millis;

void systick_init(void) {
  SysTick->CTLR = 0x0000;
  SysTick->CMP = SysTick->CNT + SYSTICK_ONE_MILLISECOND;
  systick_millis = 0;
  SysTick->CTLR = SYSTICK_CTLR_STE |   // Enable Counter
                  SYSTICK_CTLR_STIE |  // Enable Interrupts
                  SYSTICK_CTLR_STCLK;  // Set Clock Source to HCLK/1

  NVIC_EnableIRQ(SysTick_IRQn);
}

void SysTick_Handler(void) __attribute__((interrupt));
void SysTick_Handler(void) {
  SysTick->CMP = SysTick->CNT + SYSTICK_ONE_MILLISECOND;
  SysTick->SR = 0;
  systick_millis++;
}